Patent Application
20070166676
The following applications are related to the present application:
This invention relates in general to the use of brain health programs utilizing brain plasticity to enhance human performance and correct neurological disorders, and more specifically, to a method for improving the ability of the visual nervous system to perform eye movements efficiently, and to improve cognition.
Almost every individual has a measurable deterioration of cognitive abilities as he or she ages. The experience of this decline may begin with occasional lapses in memory in one's thirties, such as increasing difficulty in remembering names and faces, and often progresses to more frequent lapses as one ages in which there is passing difficulty recalling the names of objects, or remembering a sequence of instructions to follow directions from one place to another. Typically, such decline accelerates in one's fifties and over subsequent decades, such that these lapses become noticeably more frequent. This is commonly dismissed as simply “a senior moment” or “getting older.” In reality, this decline is to be expected and is predictable. It is often clinically referred to as “age-related cognitive decline,” or “age-associated memory impairment.” While often viewed (especially against more serious illnesses) as benign, such predictable age-related cognitive decline can severely alter quality of life by making daily tasks (e.g., driving a car, remembering the names of old friends) difficult.
Many daily tasks require extraction of visual information from a scene quickly and accurately. Avoiding dangers when driving a car, scanning a crowd for a familiar face, and reading quickly are a few examples of situations where visual information must be extracted quickly to perform well. Searching a scene involves two main processes. First, eyes make saccades—very rapid movements from one object to another. Second, the brain quickly captures information from each eye fixation so that the next saccade can be made. Efficient eye-movements and information processing are important for rapidly obtaining information from a scene.
As people get older, the frequency of rapid fixation eye-movements (“saccades”) declines, as does their accuracy. In addition, the time required to extract relevant information from the visual scene during each fixation (between saccades) increases. As a result, the ability to extract information quickly and accurately from a visual scene declines. In daily life, tasks that had been easy—like scanning a newspaper article for important details—get harder. This is important for tasks such as driving and crossing the road, as well as for reading speed and accuracy.
In many older adults, age-related cognitive decline leads to a more severe condition now known as Mild Cognitive Impairment (MCI), in which sufferers show specific sharp declines in cognitive function relative to their historical lifetime abilities while not meeting the formal clinical criteria for dementia. MCI is now recognized to be a likely prodromal condition to Alzheimer's Disease (AD) which represents the final collapse of cognitive abilities in an older adult. The development of novel therapies to prevent the onset of this devastating neurological disorder is a key goal for modem medical science.
The majority of the experimental efforts directed toward developing new strategies for ameliorating the cognitive and memory impacts of aging have focused on blocking and possibly reversing the pathological processes associated with the physical deterioration of the brain. However, the positive benefits provided by available therapeutic approaches (most notably, the cholinesterase inhibitors) have been modest to date in AD, and are not approved for earlier stages of memory and cognitive loss such as age-related cognitive decline and MCI.
Cognitive training is another potentially potent therapeutic approach to the problems of age-related cognitive decline, MCI, and AD. This approach typically employs computer- or clinician-guided training to teach subjects cognitive strategies to mitigate their memory loss. Although moderate gains in memory and cognitive abilities have been recorded with cognitive training, the general applicability of this approach has been significantly limited by two factors: 1) Lack of Generalization; and 2) Lack of enduring effect.
Lack of Generalization: Training benefits typically do not generalize beyond the trained skills to other types of cognitive tasks or to other “real-world” behavioral abilities. As a result, effecting significant changes in overall cognitive status would require exhaustive training of all relevant abilities, which is typically infeasible given time constraints on training.
Lack of Enduring Effect: Training benefits generally do not endure for significant periods of time following the end of training. As a result, cognitive training has appeared infeasible given the time available for training sessions, particularly from people who suffer only early cognitive impairments and may still be quite busy with daily activities.
As a result of overall moderate efficacy, lack of generalization, and lack of enduring effect, no cognitive training strategies are broadly applied to the problems of age-related cognitive decline, and to date they have had negligible commercial impacts. The applicants believe that a significantly innovative type of training can be developed that will surmount these challenges and lead to fundamental improvements in the treatment of age-related cognitive decline. This innovation is based on a deep understanding of the science of “brain plasticity” that has emerged from basic research in neuroscience over the past twenty years, which only now through the application of computer technology can be brought out of the laboratory and into the everyday therapeutic treatment.
Thus, improved systems and methods for improving the ability of the visual nervous system of a participant to perform eye movements efficiently, and to improve cognition.
Various embodiments of a system and method are presented for performing a computer-based exercise to renormalize and improve the ability of the visual nervous system of a participant to perform eye movements efficiently, and to improve cognition. More specifically, the exercise may operate to improve the efficiency of saccades and decrease the time it takes to extract accurate information from a scene.
In embodiments of this exercise, the participant is required to move his or her gaze rapidly to a series of targets presented on the monitor in a specific order, and obtain information from each target fixation. The participant then responds to this information, where the type of response required depends upon the particular version of the exercise. Note that the information contained in each stimulus should be small enough to require the participant to move their fixation to the target to process it.
It should be noted that various embodiments of the Eye Movement exercise described herein, and/or other eye movement tasks, may be used singly or in combination in the exercise. Moreover, as described below, in some embodiments, stimulus threshold assessments may also be performed in conjunction with, or as part of, the exercise, thus facilitating more effective training of the participant's cognitive systems, e.g., memory and visual processing systems.
First, multiple graphical elements may be provided, where each graphical element has a value, and where the multiple graphical elements are available for visual presentation to the participant. In other words, a set of images may be provided where each image has or is associated with a respective value. For example, as will be discussed below in detail, examples of such graphical elements include, but are not limited to, images of numbers, playing cards, and letter tiles, among others.
Next, a temporal sequence of at least two of the graphical elements may be visually presented at a specified stimulus intensity, including displaying the value of each of the at least two graphical elements at a respective position in a visual field for a specified duration, then ceasing to display the value. Said another way, a series of two or more graphical elements (from the multiple graphical elements) may be displayed in sequence at a specified stimulus intensity, where each of the graphical elements is displayed at a respective location in the visual field, e.g., in a display area of a graphical user interface (GUI). The value of each graphical element may be displayed (at its respective position) for a specified period of time, i.e., a duration, then the respective value is removed from view, e.g., hidden, not displayed, etc. Note that in various embodiments, the displayed values of the graphical elements may be any of a variety of values, such as, for example, numbers, letters, colors, and/or shapes, among others. In one embodiment, visually presenting the temporal sequence of at least two of the graphical elements includes visually presenting the at least two graphical elements at a specified stimulus intensity. Note that as used herein, the term stimulus intensity refers to any adjustable stimulus attribute or adaptive dimension that may be modified to increase or decrease the difficulty of a task. For example, in some embodiments, the stimulus intensity may be the presentation time or duration of each value, and/or the inter-stimulus interval. In some embodiments, the duration of the display of each value and the duration of the inter-stimulus interval (ISI) may together form the stimulus intensity, and may be referred to as the duration of the stimulus. In other words, in various embodiments, the duration may refer to the duration of the display of the values and/or the ISI. Thus, the stimulus intensity may be compound or complex.
It should be noted that while in preferred embodiments, the stimulus intensity may be or include the duration, in other embodiments, the stimulus intensity may include one or more of: the eccentricity of the respective positions of the least two graphical elements in the visual field, the number of graphical elements in the temporal sequence, and/or the appearance or visual emphasis of the graphical elements, e.g., the size, contrast, color, homogeneity, etc., of the graphical elements in the visual field, among others. In other words, the stimulus intensity may refer to any adjustable attribute of the stimulus and/or its presentation that may be modified to increase or decrease the difficulty of trials in the exercise.
In preferred embodiments, the participant may perform the exercise via a graphical user interface (GUI). The GUI may include a visual field or display area, e.g., a stimulus presentation area where the sequences of graphical elements of may be presented to the participant. In some embodiments, the visual field may include a fixation point, which may be displayed in the center of the visual field. The fixation point may serve as a reference point in the visual field for positioning graphical elements, and/or as a neutral point for the participant's gaze, e.g., before the sequence is presented. Note that in some embodiments, the fixation point may not be displayed.
Note that each value is displayed in a respective position in the visual field such that to view or examine each graphical element (number) in the sequence, the participant must move his or eyes across the visual field. In other words, to perceive the values presented, the participant may be required to perform saccades, quickly moving the eyes to focus at each position.
In some embodiments, the respective positions of the at least two graphical elements may be determined randomly. For example, the first graphical element of the at least two graphical elements may have a first position (randomly determined) with a first azimuth, and each subsequent graphical element of the at least two graphical elements may have an azimuth differing from that of the previous graphical element by a respective angle. In other words, the position of the first graphical element in the presented sequence may be randomly chosen or selected, possibly subject to one or more constraints, e.g., range constraints, as will be discussed below. This first position has an azimuthal angle with respect to some reference vector, e.g., a vector from the center fixation point straight up to the center of the top edge of the visual field. Each succeeding graphical element/value may be positioned by randomly determining a distance from the fixation point (again, possibly subject to one or more constraints), and randomly determining respective angle, i.e., an angular offset, from the azimuth of the first graphical element.
In one embodiment, the values of the sequenced graphical elements may be displayed in respective “patches” or local backgrounds, e.g., to aid or hinder the participant's perception of the values. For example, in one embodiment, each value may be displayed in a respective Gabor patch in the visual field, where, as used herein, a Gabor patch refers to a windowed sine-wave modulated grating or pattern that varies in luminance (roughly equivalent to the phenomenal experience of lightness) as a sine function of space along a particular direction or orientation, e.g., windowed by a 2-dimensional Gaussian to remove sharp edges which otherwise introduce high spatial frequency intrusions. Each Gabor patch may have a respective orientation, where, after a first displayed value of the at least two graphical elements, each Gabor patch orientation may be rotated a specified amount with respect to an immediately previous Gabor patch. In other embodiments, other background patches may be used as desired.
The participant may then be required to respond to the displayed values. For example, in an embodiment where a series of numbers are presented in temporal sequence, the participant may be required to input or otherwise indicate the numeric sequence, e.g., via a keyboard coupled to the computing device, although any other means may be used as desired. In other words, requiring the participant to respond to the displayed values may include requiring the participant to indicate the sequence of the displayed values. As will be described in detail below, other embodiments of the exercise may use other types of graphical elements (besides simple numbers), and may require correspondingly different responses from the participant.
A determination may be made as to whether the participant responded correctly. For example, following the above-described embodiment, a determination may be made as to whether the participant correctly indicated the numeric sequence. In preferred embodiments, the method may include audibly and/or graphically indicating whether the participant responded correctly. In embodiments where the participant's response includes a plurality of selections, indicating whether the participant responded correctly may include indicating whether the participant's selection is correct for each selection, e.g., for each selection, an indicative sound, such as a “ding” or “thunk” (and/or a graphical indication) may be played indicating whether that selection were correct or incorrect, respectively. In some embodiments, points may be awarded (in the case of a correct response and/or selection). Of course, any other type of indication may be used as desired. For example, in embodiment where a trial includes multiple selections, a first sound, e.g., a wind sound, may be played when the participant makes a correct selection, and a second sound, e.g., a chime sound, may be played when the participant has made all selections in the trial correctly.
In some embodiments, each response of the participant may be recorded. Similarly, in some embodiments, the method may include recording whether the participant responded correctly. For example, the responses and/or their correctness/incorrectness may be stored in a memory medium of the computing device, or coupled to the computing device.
The stimulus intensity, e.g., duration, may then be modified based on the above determining. Of course, as mentioned above, the stimulus intensity may be any adjustable attribute of the graphical elements and/or their presentation, and so modifying the stimulus intensity may include modifying any of these adjustable attributes as desired. Modifying the stimulus intensity based on said determining preferably includes adjusting the stimulus intensity for the visually presenting based on whether the participant responded correctly. In one embodiment, the adjusting may be performed using a maximum likelihood procedure, such as, for example, a QUEST (quick estimation by sequential testing) threshold procedure, and/or a ZEST (zippy estimation by sequential testing) threshold procedure, e.g., a single-stair maximum likelihood procedure.
In one embodiment, adjusting the stimulus intensity may include decreasing the duration if the participant responds correctly, and increasing the duration if the participant responds incorrectly, although other attributes may be adjusted as desired. Thus, for example, in one embodiment, the duration may be set initially at 500 ms, and may adapt based on performance. In one modification scheme, after a correct response the duration may be multiplied by 0.8, and after an incorrect response, divided by 0.8. The inter-stimulus interval may be fixed at 200 ms for every trial. In some embodiments, the duration may have minimum and maximum values, e.g., a minimum of 40 ms, and a maximum of 1000 ms. Of course, other modification schemes (and other ISI values) may be used as desired.
The visually presenting, requiring, determining, and modifying may be repeated one or more times in an iterative manner to improve the participant's cognitive skills. For example, the repetitions may be performed over a plurality of sessions, e.g., over days, weeks, or even months, e.g., for a specified number of times per day, and for a specified number of days.
The above described visually presenting, requiring, determining, and modifying may compose performing a trial in the exercise. In preferred embodiments, the repeating may include performing a plurality of trials under each of a plurality of conditions, where each condition specifies one or more attributes of the at least two graphical elements or their presentation.
In some embodiments, over the course of performing the plurality of trials, the stimulus intensity may be adjusted to approach and substantially maintain a specified success rate for the participant. For example, the stimulus intensity may be adjusted to approach and substantially maintain a specified success rate for the participant uses a single stair maximum likelihood procedure. Moreover, in further embodiments, the adjusting the stimulus intensity to approach and substantially maintain a specified success rate for the participant may be performed for each of the plurality of conditions.
In some embodiments, during the performance of the exercise, assessments may be made periodically, e.g., using a maximum likelihood procedure, e.g., a 2-stair maximum likelihood procedure, e.g., a 2-stair ZEST procedure, to determine or characterize the participant's progress in performing the exercise.
Other features and advantages of the present invention will become apparent upon study of the remaining portions of the specification and drawings.
Referring to
Now referring to
Overview of the Eye Movement Exercise
Embodiments of the computer-based exercise described herein may operate to renormalize and improve the ability of the visual nervous system of a participant to perform eye movements efficiently, and to improve cognition. More specifically, the exercise may operate to improve the efficiency of saccades and decrease the time it takes to extract accurate information from a scene.
In embodiments of this exercise, the participant is required to move his or her gaze rapidly to a series of targets presented on the monitor in a specific order, and obtain information from each target fixation. The participant then responds to this information, where the type of response required depends upon the particular version of the exercise. Note that the information contained in each stimulus should be small enough to require the participant to move their fixation to the target to process it.
It should be noted that various embodiments of the Eye Movement exercise described herein, and/or other eye movement tasks, may be used singly or in combination in the exercise. Moreover, as described below, in some embodiments, stimulus threshold assessments may also be performed in conjunction with, or as part of, the exercise, thus facilitating more effective training of the participant's cognitive systems, e.g., memory and visual processing systems.
In 302, multiple graphical elements may be provided, where each graphical element has a value, and where the multiple graphical elements are available for visual presentation to the participant. In other words, a set of images may be provided where each image has or is associated with a respective value. For example, as will be discussed below in detail, examples of such graphical elements include, but are not limited to, images of numbers, playing cards, and letter tiles, among others.
In 304, a temporal sequence of at least two of the graphical elements may be visually presented at a specified stimulus intensity, including displaying the value of each of the at least two graphical elements at a respective position in a visual field for a specified duration, then ceasing to display the value. Said another way, a series of two or more graphical elements (from the multiple graphical elements of 302) may be displayed in sequence at a specified stimulus intensity, where each of the graphical elements is displayed at a respective location in the visual field, e.g., in a display area of a graphical user interface (GUI). The value of each graphical element may be displayed (at its respective position) for a specified period of time, i.e., a duration, then the respective value is removed from view, e.g., hidden, not displayed, etc. Note that in various embodiments, the displayed values of the graphical elements may be any of a variety of values, such as, for example, numbers, letters, colors, and/or shapes, among others.
As used herein, the term stimulus intensity refers to any adjustable stimulus attribute or adaptive dimension that may be modified to increase or decrease the difficulty of a task. For example, in some embodiments, the stimulus intensity may be the presentation time or duration of each value, and/or the inter-stimulus interval. In some embodiments, the duration of the display of each value and the duration of the inter-stimulus interval (ISI) may together form the stimulus intensity, and may be referred to as the duration of the stimulus. In other words, in various embodiments, the duration may refer to the duration of the display of the values and/or the ISI. Thus, the stimulus intensity may be compound or complex.
It should be noted that while in preferred embodiments, the stimulus intensity may be or include the duration, in other embodiments, the stimulus intensity may include one or more of: the eccentricity of the respective positions of the least two graphical elements in the visual field, the number of graphical elements in the temporal sequence, and/or the appearance or visual emphasis of the graphical elements, e.g., the size, contrast, color, homogeneity, etc., of the graphical elements in the visual field, among others. In other words, the stimulus intensity may refer to any adjustable attribute of the stimulus and/or its presentation that may be modified to increase or decrease the difficulty of trials in the exercise.
As indicated above, in preferred embodiments, the participant may perform the exercise via a graphical user interface (GUI).
In some embodiments, the respective positions of the at least two graphical elements may be determined randomly. For example, the first graphical element of the at least two graphical elements may have a first position (randomly determined) with a first azimuth, and each subsequent graphical element of the at least two graphical elements may have an azimuth differing from that of the previous graphical element by a respective angle. In other words, the position of the first graphical element in the presented sequence may be randomly chosen or selected, possibly subject to one or more constraints, e.g., range constraints, as will be discussed below. This first position has an azimuthal angle with respect to some reference vector, e.g., a vector from the center fixation point straight up to the center of the top edge of the visual field. For example, referring back to
For example, in one embodiment, the respective angle is a randomly determined angle between approximately 90 and approximately 180 degrees, or between approximately −90 and approximately −180 degrees. Mathematically expressed, the angle may be +/−(90+random(90)) degrees. A primary purpose of the different positions of the graphical elements is to force the participant to move his or her eyes substantially to focus on each graphical element. Of course, other schemes for distributing the graphical elements in the visual field may be used as desired. For example, in some embodiments, one or more low discrepancy sequences may be used to select or determine positions of the graphical elements in the visual field.
In one embodiment, the values of the sequenced graphical elements may be displayed in respective “patches” or local backgrounds, e.g., to aid or hinder the participant's perception of the values. For example, as illustrated in
Note that the embodiment illustrated in
In 306, the participant may be required to respond to the displayed values. For example, following the exemplary embodiment of
In 308, a determination may be made as to whether the participant responded correctly. For example, following the embodiment of
Following the embodiment of
In some embodiments, each response of the participant may be recorded. Similarly, in some embodiments, the method may include recording whether the participant responded correctly. For example, the responses and/or their correctness/incorrectness may be stored in a memory medium of the computing device, or coupled to the computing device.
In 310, the stimulus intensity, e.g., duration, may then be modified based on the above determining. Of course, as mentioned above, the stimulus intensity may be any adjustable attribute of the graphical elements and/or their presentation, and so modifying the stimulus intensity may include modifying any of these adjustable attributes as desired. Modifying the stimulus intensity based on said determining preferably includes adjusting the stimulus intensity for the visually presenting based on whether the participant responded correctly.
In one embodiment, the adjusting may be performed using a maximum likelihood procedure, such as, for example, a QUEST (quick estimation by sequential testing) threshold procedure, and/or a ZEST (zippy estimation by sequential testing) threshold procedure, e.g., a single-stair maximum likelihood procedure, as described below in more detail.
In one embodiment, adjusting the stimulus intensity may include decreasing the duration if the participant responds correctly, and increasing the duration if the participant responds incorrectly. Thus, for example, in one embodiment, the duration may be set initially at 500 ms, and may adapt based on performance. In one modification scheme, after a correct response the duration may be multiplied by 0.8, and after an incorrect response, divided by 0.8. The inter-stimulus interval may be fixed at 200 ms for every trial. The results of this scheme are summarized thusly:
Initial trial: <500 ms>-<200 ms>-<500 ms>-<200 ms>-<500 ms>
After correct: <400 ms>-<200 ms>-<400 ms>-<200 ms>-<400 ms>
After incorrect: <625 ms>-<200 ms>-<625 ms>-<200 ms>-<625 ms>
In some embodiments, the duration may have minimum and maximum values, e.g., a minimum of 40 ms, and a maximum of 1000 ms. Of course, other modification schemes (and other ISI values) may be used as desired.
In 312, the visually presenting, requiring, determining, and modifying may be repeated one or more times in an iterative manner to improve the participant's cognition. For example, the repetitions may be performed over a plurality of sessions, e.g., over days, weeks, or even months, e.g., for a specified number of times per day, and for a specified number of days.
The above described visually presenting, requiring, determining, and modifying may compose performing a trial in the exercise. In preferred embodiments, the repeating may include performing a plurality of trials under each of a plurality of conditions, where each condition specifies one or more attributes of the at least two graphical elements or their presentation.
In some embodiments, over the course of performing the plurality of trials, the stimulus intensity may be adjusted (i.e., the modifying of 310) to approach and substantially maintain a specified success rate for the participant. For example, the stimulus intensity may be adjusted to approach and substantially maintain a specified success rate for the participant uses a single stair maximum likelihood procedure. Moreover, in further embodiments, the adjusting the stimulus intensity to approach and substantially maintain a specified success rate for the participant may be performed for each of the plurality of conditions, as will be discussed in more detail below.
The below describes exemplary embodiments of more complex versions of the Eye Movement exercise, although it should be noted that various aspects of the embodiments described herein may be utilized with respect to any other embodiments of the exercise as desired.
In one embodiment, visually presenting the temporal sequence of at least two of the graphical elements may include visually presenting a first plurality of the graphical elements in a spatial arrangement in the visual field, where each graphical element in the first plurality of graphical elements has a respective position, and where the at least two graphical elements are included in the first plurality of graphical elements. In other words, prior to displaying the sequence of (at least two) graphical elements, the set of graphical elements from which the sequence of graphical elements are taken may be presented in the visual field in a specified arrangement. The particular arrangements used may be specified by the conditions under which trials are performed.
For example, where the visual field has a fixation point in the center of the visual field (see, e.g.,
Other aspects of the sequence of graphical elements or their presentation may include: the number of graphical elements in the first plurality of graphical elements, the number of graphical elements in the presented sequence of the at least two graphical elements, whether the durations of the visually presenting overlap, complexity of the graphical elements, and/or visual emphasis, i.e., distinguishability of the graphical elements from a background displayed in the visual field, among others.
Thus, over the course of the exercise, the conditions may range from easier to more difficult. For example, the conditions may include combinations of various categories of attributes of the graphical elements or their presentation. Examples of the categories include: gap/overlap categories, where in the gap category, the current stimulus disappears before the next one is presented, and in the overlap category, the current stimulus remains on for a short period of time (e.g. 0.25 s) after the next one is presented; stimulus complexity categories, where, in the easy categories, stimuli may be easy (e.g. data strings embedded in Gabor patch stimuli that rotate orthogonally on each presentation), while in more advanced stimulus categories, the stimuli may be objects (e.g. faces, pictures, cards); emphasis level categories, where at easier levels, the presented values may be easily distinguishable from the background, and at harder levels, the values may be less distinct from the background information; serial or sequence size categories, where a beginning level may start with an easier serial size (e.g. 2 items), and at higher levels, the size may expand to 3 and 4; and stimuli distance categories, where each level may have an associated annular distance (and possibly thickness) for display of the first plurality of graphical elements (which also applies to the presented sequences, since they are from this first plurality of graphical elements). However, these various conditions, categories, levels, and progressions are meant to be exemplary only, and are not intended to limit the exercise to any particular set of conditions, categories, levels, or progressions.
Note that displaying the first plurality of graphical elements does not include displaying their values, but rather, establishes spatial positions for any graphical elements selected for the visually presented sequences. Moreover, in some embodiments, when, or prior to, the visual presentation of the at least two graphical elements (and their values), the first plurality of graphical elements may be removed from view. In other words, the first plurality of graphical elements may disappear from the visual field before the particular sequence of graphical elements (and their values) are visually presented.
Card Match
In this version of the exercise, visually presenting the first plurality of the graphical elements in a spatial arrangement in the visual field may include visually presenting a first plurality of the playing cards face down (meaning with their values not displayed) at respective positions in the visual field, i.e., the values of the graphical elements are not displayed. Similarly, the at least two graphical elements are at least two playing cards, and visually presenting the temporal sequence of at least two of the graphical elements includes revealing the respective values of the at least two playing cards in sequence, where for each of the at least two playing cards, the value is displayed for the duration, then the playing card is turned face down. In some embodiments, revealing the respective values of the at least two playing cards in sequence may include displaying the values of the at least two playing cards in sequence for respective durations, separated by a specified inter-stimulus interval (ISI). In various embodiments, the ISI may be held constant, e.g., at 200 ms, as mentioned above, or may be adjusted, e.g., as part of the duration, or as specified by the various conditions under which trials are performed. Note, for example, that negative values for the ISI result in overlap between the durations or presentation times of the values, where, for example, each succeeding value is presented before the previous value is removed from view.
In one embodiment, visually presenting the temporal sequence of at least two of the graphical elements may include highlighting the at least two cards, where after turning the at least two playing cards face down, the highlighting is maintained. This may reduce confusion in the participant regarding which of the first plurality of cards were sequenced. In some embodiments, prior to the revealing of values of the sequence of playing cards, the first plurality of playing cards may be removed from view. In other words, just before the sequence is visually presented, the first plurality of graphical elements, in this case, the first plurality of playing cards, may disappear.
As described above, in one embodiment, the respective positions of the visually presented graphical elements (in this case, playing cards) may be determined randomly, e.g., where the position of the first graphical element of the at least two graphical elements is randomly selected, and has a first azimuth, and where each subsequent graphical element of the at least two graphical elements is positioned at a random distance from the center of the visual field, and an azimuth differing from that of the previous graphical element by a respective randomly determined angle. The respective angle may be a randomly determined angle between approximately 90 and approximately 180 degrees, or between approximately −90 and approximately −180 degrees. Mathematically expressed, the angle may be +/−(90+random(90)) degrees. As noted above, a primary purpose of the different positions of the graphical elements is to force the participant to move his or her eyes substantially to focus on each graphical element. However, other schemes for distributing the graphical elements in the visual field may be used as desired.
As
Note that any other GUI elements may be included as desired. For example, in some embodiments, the GUI may include one or more of: a time remaining indicator that provides an indication of how much time remains in the current task, session, or exercise, a threshold field that displays stimulus threshold information, such as the current threshold value and a best threshold value, where a threshold indicates or is the value of the adjustable stimulus intensity, that results in a specified performance level, i.e., success rate, for the participant, as will be explained below in more detail. However, it should be noted that these particular GUI elements are meant to be exemplary only, and are not intended to limit the GUIs contemplated to any particular form, function, or appearance.
In some embodiments, a second plurality of playing cards may be displayed face up, where the second plurality of playing cards includes playing cards with the same values as the at least two playing cards, and one or more distracter cards with different values. As indicated above, in this embodiments, requiring the participant to respond to the displayed values includes requiring the participant to indicate matches between each of the at least two playing cards and respective ones of the second plurality of playing cards. In other words, once the values of the visually presented sequence of playing cards have been displayed or revealed (and then flipped, hidden, or otherwise removed from view), the second plurality of playing cards are displayed, and the participant may successively indicate matches between each playing card in the sequence and one of the second plurality of playing cards. For example, in one embodiment, requiring the participant to indicate matches between each of the at least two playing cards and respective ones of the second plurality of playing cards may include: for each playing card of the at least two playing cards: receiving input from the participant selecting one of the at least two playing cards, and receiving input from the participant selecting a playing card from the second plurality of playing cards as a match for the selected one of the at least two playing cards, e.g., by clicking on each card with a mouse.
In some embodiments, if a card is incorrectly matched, the incorrectness of the selection may be indicated, e.g., with a “thunk” sound, the (e.g., six) cards in the middle of the screen may disappear, the trial may be terminated, and the start button may appear. If all three cards are correctly matched, the correctness of the selection may be indicated, e.g., with a “chime” sound, bonus points may be awarded, the (e.g., six) cards in the middle of the screen may disappear, and the start button may appear.
Note that in embodiments directed to playing cards, such as described above, the conditions under which trials are performed may specify further aspects of the graphical elements or their presentation. For example, in some embodiments, each of the plurality conditions may further specify whether the at least two playing cards are of the same suit, and/or whether the suit of the at least two playing cards can change for each trial.
In some embodiments, bonus points may be awarded and indicated, e.g., for when the participant successfully performs a trial, e.g., matches all the sequenced cards correctly, or, as another example, when the participant successfully performs a specified number of trials consecutively, e.g., 5 times in a row. Thus, in some embodiments, the GUI may also include a bonus meter (or equivalent), which may indicate such bonus awards. Note that this may be in addition to the awarding of bonus points. One embodiment of such a bonus indicator is included in the score display of
As noted above, the exercise may include performing trials in a plurality of levels. For example, in one exemplary embodiment of the Card Match version of the exercise, there may be two levels based on the relative closeness of the cards to the central fixation point and the number of suits. For example, in level 1, all cards in all trials may be of the same suit, and the cards may be distributed closer to a central fixation point (see, e.g.,
In one embodiment, the participant may be able to choose to start Card Match at level 1, e.g., by choosing an “Easy” button, or at level 2, e.g., by choosing a “Hard” button, in an introductory screen. If Card Match is started at level 1, the participant may advance to level 2 after having filled in the gold circle around the score (e.g., 12 correct trials), as illustrated in
It should be noted that the Card Match version of the exercise described herein is meant to be exemplary, and such matching versions of the exercise may be performed using any other types of graphical elements and values desired, e.g., tokens, coins, or other elements with values based on colors, shapes, pictures, etc.
Word Finder
In this version of the exercise, visually presenting the first plurality of the graphical elements in a spatial arrangement in the visual field may include visually presenting a first plurality of the tiles face down (meaning with their values not displayed) at respective positions in the visual field, i.e., the values of the graphical elements are not displayed. Similarly, the at least two graphical elements are at least two tiles, and visually presenting the temporal sequence of at least two of the graphical elements includes revealing the respective values of the at least two tiles in sequence, where for each of the at least two tiles, the value is displayed for the duration, then the tile is turned face down, i.e., the value ceases to be displayed. Note, however, that in this version of the exercise, the respective letters of the at least two tiles in sequence are a scrambled word. In other words, the sequence of letters (temporarily) presented form a scrambled word, which the participant is expected to unscramble.
As with the Card Match version, in some embodiments, revealing the respective letters of the at least two tiles in sequence may include displaying the letters of the at least two tiles in sequence for respective durations, separated by a specified inter-stimulus interval (ISI), which in various embodiments, may be held constant, e.g., at 200 ms, as mentioned above, or may be adjusted, e.g., as part of the duration, or as specified by the various conditions under which trials are performed.
In one embodiment, the values (e.g., letters) may be assigned to the visually presented graphical elements (e.g., tiles) dynamically. For example, first, the letters of the word may be scrambled, and then each letter (of the scrambled word) may be associated with and presented on the selected tiles, i.e., on the sequence of tiles being visually presented. In other words, in some embodiments, values may not be assigned to graphical elements until the graphical elements are visually presented in sequence.
Note that in some embodiments, the graphical elements of the visually presented sequence may already have respective positions, e.g., as part of the first plurality of graphical elements. In these embodiments, the graphical elements may be selected for inclusion in the sequence by randomly determining the positions, as described above, then selecting the graphical elements (from the first plurality of graphical elements) that are closest to these positions.
In preferred embodiments, visually presenting the temporal sequence of at least two of the graphical elements may include highlighting the at least two tiles, where after turning the at least two tiles face down, the highlighting is maintained, thereby indicating to the participant which of the first plurality of tiles were sequenced. In some embodiments, prior to the revealing of letters of the sequence of tiles, the first plurality of tiles may be removed from view, as described above (and shown in
Once the sequence of
Similar to the Card Match version of the exercise, in some embodiments, rather than displaying the first plurality of tiles in a rectangular grid, as shown in
Thus, in one specific exemplary embodiment, a trial may proceed as follows: a sequence of letters that form a three-letter word may be presented randomly one after the other on a circular grid of letter tiles, where each letter is presented briefly on a blank tile before that tile again becomes blank. The tile on which the letter appeared may be highlighted. Additionally, the presentation time for each letter may be the same but may change based on performance. The participant is expected to unscramble and identify the three-letter word. The participant may click on one of the highlighted tiles on which the letters appeared, the letter beneath that tile may be revealed and may be displayed under the score, e.g., in the letter or word display, and a “pop” sound may be played. This may be repeated until all three letters are revealed. If the word is correctly identified, a “ding” sound may play, points may be awarded, the word may be highlighted or displayed under the score, and the start button may appear. If the word is incorrectly identified, a “thunk” sound may play, the word may be removed from under the score, and the start button may appear.
As mentioned above, in preferred embodiments, the modification or adjustment of the stimulus intensity, e.g., the duration of each visual presentation of the value of each graphical element in the sequence, may be performed repeatedly over the course of the exercise based on the correctness or incorrectness of the participant's responses. The adjustments may generally be made to increase the difficulty of the stimulus when the participant answers correctly (e.g., shortening the duration or presentation time), and to decrease the difficulty of the stimulus when the participant answers incorrectly (e.g., increasing the duration or presentation time). Moreover, the adjustments may be made such that a specified level of performance, i.e., level of success, is approached and substantially maintained during performance of the exercise. For example, based on the participant's responses, the stimulus intensity may be adjusted to substantially achieve and maintain a specified success rate, e.g., 85% for the participant, although other rates may be used as desired.
As also mentioned above, in preferred embodiments, the adjustments may be made using a maximum likelihood procedure, such as a QUEST (quick estimation by sequential testing) threshold procedure, or a ZEST (zippy estimation by sequential testing) threshold procedure, described below, such procedures being well-known in the art of stimulus threshold determination. In some embodiments, these adjustments (e.g., using ZEST) may be determined on a per condition basis. In other words, for each condition (used in each task), the sequences may be presented (and adjusted) in accordance with a maximum likelihood procedure (e.g., ZEST) applied to trials under that condition.
Moreover, as described below, the repeating may also include performing threshold assessments in conjunction with, or as part of, the exercise. In other words, the method of
Threshold Determination/Assessment
As indicated above, stimulus intensity is an adjustable attribute of a presented stimulus whereby a trial in the exercise may be made more or less difficult. For example, in one embodiment, the stimulus intensity may be the duration of the stimulus presentation, i.e., the presentation time (possibly including the ISI), although other attributes of the stimulus may be used as desired. The term “threshold” refers to the value of the stimulus intensity at which the participant achieves a specified level of success, e.g., 0.9, corresponding to a 90% success rate. Thus, any other attribute or combination of attributes may be used as desired, the term stimulus intensity being intended to refer to any such adjustable attributes.
Exercise based assessments (i.e., threshold determination) are designed to assess a participant's threshold with respect to stimuli on a given exercise, and can be used to adjust stimulus presentation to (substantially) achieve and maintain a desired success rate for the participant, e.g., with respect to a particular exercise, task, or condition. As will be described below, such threshold determination may also be used to assess or determine a pre-training threshold that can then be used to calibrate the program to an individual's capabilities on various exercises, as well as serve as a baseline measure for assessing the participant's performance periodically during an exercise. Such assessment may also serve as a baseline measure to which post-training thresholds can be compared. Comparison of pre-training to post-training thresholds may be used to determine the gains made as a function of training with the cognition enhancement exercise or tasks described herein.
As noted above, there are various approaches whereby such thresholds may be assessed or determined, such as, for example, the well known QUEST (Quick Estimation by Sequential Testing) threshold method, which is an adaptive psychometric procedure for use in psychophysical experiments, or a related method, referred to as the ZEST (Zippy Estimation by Sequential Testing) procedure or method, among others, although it should be noted that such methods have not heretofore been utilized in cognition enhancement training exercises using eye movement, as described herein.
The ZEST procedure is a maximum-likelihood strategy to estimate a subject's threshold in a psychophysical experiment based on a psychometric function that describes the probability a stimulus is detected as a function of the stimulus intensity. For example, consider a cumulative Gaussian psychometric function, F(x−T), for a 4-alternative-forced-choice (afc) task with a 5% lapsing rate, with proportion correct (ranging from 0-1) plotted against intensity of the stimulus (ranging from 0-5). As used herein, the term intensity (with respect to stimuli) refers to the value of the adaptive dimension variable being presented to the participant at any particular trial in a particular exercise. In other words, the intensity value is that parameter regarding the exercise stimuli that may be adjusted or adapted, e.g., to make a trial more or less difficult. For example, in preferred embodiments of the Eye Movement exercise, the intensity value is the duration or presentation time (e.g., in milliseconds) of the presented values of the sequence of graphical elements (possibly including the ISI). The threshold is defined to be the mean of the Gaussian distribution for a specified success rate—e.g., a value yielding some specified success rate, e.g., 60%, which corresponds to an intensity of 2.
The method may make some assumptions about the psychophysics:
The primary idea of the ZEST procedure is as follows: given a prior probability density function (P.D.F.) centered around the best threshold guess, x, this P.D.F. is adjusted after each trial by one of two likelihood functions, which are the probability functions that the subject will respond “yes” or “no” to the stimulus at intensity as a function of threshold. Since the psychometric function has a constant shape and is of the form F(x−T), fixing the intensity x and treating threshold T as the independent variable, the “yes” likelihood, p=F(−(T−x)), is thus the mirror image of the psychometric function about the threshold, and the “no” likelihood function is then simply 1−p.
The P.D.F. is updated using Bayes' rule, where the posterior P.D.F. is obtained by multiplying the prior P.D.F. by the likelihood function corresponding to the subject's response to the trial's stimulus intensity. The mean of the updated (or posterior) P.D.F. is then used as the new threshold estimate and the test is repeated with the new estimate until the posterior P.D.F. satisfies a confidence interval criteria (e.g. standard deviation of posterior P.D.F.<predetermined value) or a maximum number of trials is reached.
In one example of the ZEST procedure, a single trial of a 4-afc experiment is performed, with x=2.5 (intensity) as the initial threshold guess. If the subject responds correctly, the next trial is placed at the mean of the corresponding posterior P.D.F., ˜x=2.3; if the response is incorrect, the next trial is placed at the mean of the corresponding P.D.F., ˜x=2.65.
Thus, in some embodiments, a single stair ZEST procedure such as that described above may be used to adjust the intensity of the stimuli for the Eye Movement exercise during training. In contrast, in some embodiments, particularly with respect to the periodic assessments during the exercise (as opposed to the “per response” stimulus adjustment) a 2-stair ZEST procedure may be employed, where two independent tracks with starting values, preferably encompassing the true threshold, each running its own ZEST procedure, are randomly interleaved in the threshold seeking procedure. In addition to their individual termination criterion, the difference between the two stairs may also be required to be within a specified range, e.g., the two stairs may be constrained to be a predetermined distance apart. An exemplary implementation of this approach is described below with respect to the eye movement threshold assessment.
As used herein, the parameters required for ZEST may include the mean of the prior P.D.F. (threshold estimate), the standard deviation of the prior P.D.F. (spread of threshold distribution), the standard deviation of the cumulative Gaussian distribution (slope of psychometric function), the maximum number of trials to run, and a confidence level and interval. Additionally, in one embodiment, the trial-by-trial data saved for analysis may include: the track used, the stimulus intensity presented, the subject's response, the mean of posterior P.D.F., and the standard deviation of the posterior P.D.F., as well as any other data deemed necessary or useful in determining and/or assessing the participant's threshold.
Thus, in preferred embodiments, a maximum likelihood procedure, such as a ZEST procedure, may be used to adjust the stimulus intensity (e.g., duration) of the presented sequences during training (e.g., via a single stair ZEST procedure per condition), and may also be used for assessment purposes at periodic stages of the exercise (e.g., via a dual stair ZEST procedure, describe below). In one embodiment, such assessment may occur at specified points during the exercise, e.g., at 0% (i.e., prior to beginning), 25%, 50%, 75%, and 100% (i.e., after completion of the exercise) of the exercise. An example of such assessment is now described.
A primary purpose of the Eye Movement threshold assessment is to determine the smallest stimulus intensity, e.g., duration, in an eye movement task that a person can respond correctly to above a statistical threshold. The Eye Movement assessment may be similar to the Eye Movement exercise with respect to visual presentation, where the differences between the assessment and the exercise lie (at least primarily) in the movement or progression through the task and the data that are obtained from this movement for the assessment. The procedure is designed to obtain a threshold, which is a statistical rather than an exact quantity. In one embodiment, for the purposes of this exercise, the threshold may be defined as the smallest stimulus intensity, e.g., duration of stimulus duration or presentation time (in milliseconds) for each value (possibly including the ISI), at which the participant will fail to respond correctly a specified percentage, e.g., 69%, 85%, 90%, etc., of all trials for the task. In a preferred embodiment, being a computer based task, the Eye Movement assessment may use the ZEST procedure to progress or move through the task, adjust the stimulus intensity (e.g., duration) for the sequence, and determine the statistical threshold.
As noted above, many aspects of the Eye Movement assessment may generally be similar, or possible even identical, to the Eye Movement exercise task with respect to visual presentation. However, some aspects of the Eye Movement exercise may not be necessary in the Eye Movement assessment. For example, with regard to the GUI, in some embodiments, GUI elements such as score indicator, bonus indicator, etc., may not be necessary, and so may be omitted. Features or assets that may remain the same may include the “ding”, “thunk”, and “chime” sounds (or equivalents) that play after a participant responds correctly or incorrectly. The assessment stimulus presentation may also be identical to the training version.
The following describes one embodiment of a 2-stair (dual track) approach for determining a psychophysical threshold for a participant, e.g., an aging adult, where the task is directed to perception of presented sequences, and where the stimulus intensity comprises the stimulus presentation time (possibly including the ISI), also referred to as duration, although other attributes may be used as desired, the duration being exemplary only. Initially, first and second tracks may be initialized with respective durations based on an initial anticipated threshold, where the initial anticipated threshold is an initial estimate or guess of a duration corresponding to a specified performance level of the participant, e.g., a stimulus duration at which the participant fails to respond correctly some specified percentage of the time, e.g., 69%. For example, in one embodiment, the first track may be initialized to a first duration that is below the initial anticipated threshold, e.g., preferably just slightly below the initial anticipated threshold, and the second track may be initialized to a second duration that is (e.g., slightly) above the initial anticipated threshold. Thus, the initial durations of the two tracks may straddle the initial anticipated threshold.
The method elements 302-308 of
The duration (or more generally, the stimulus intensity) of the specified track may then be adjusted or modified, based on the participant's response (see, e.g., 310). For example, the duration of the track may be modified in accordance with a maximum likelihood procedure, such as QUEST or ZEST, as noted above. In one embodiment, for each track, modifying the duration of the specified track based on the participant's response may include increasing the duration if the participant responds incorrectly, and decreasing the duration if the participant responds correctly. Thus, for each assessment trial (in a given track), the duration for the sequence presentation for that trial may be determined by the performance of the previous trial for that track. In other words, the participant's response to the stimulus determines that track's next stimulus duration via the maximum likelihood method.
Similar to 312 of
A threshold for the participant may then be determined based on the respective final durations for the first track and the second track, where the threshold is or specifies the stimulus duration or presentation time associated with the specified performance level of the participant. For example, as mentioned above, the determined threshold may specify the duration (i.e., the presentation time) at which the participant fails to respond correctly some specified percentage of the trials, e.g., 50%, 69%, etc., although it should be noted that any other percentage may be used as desired. In one embodiment, the threshold for the participant may be determined by averaging the respective final durations for the first track and the second track. More generally, the threshold for the participant may be determined by averaging the respective final stimulus intensity values for the first track and the second track.
Thus, in one embodiment, when making an assessment, the mean of two randomly interleaved Zests may be used with estimates made at a threshold level of 50% to make the estimate (which is standard for this type of task). When training, a single staircase ZEST procedure may used with a threshold level of 85%.
In some embodiments, the method may also include performing a plurality of practice trials, i.e., prior to performing the method elements described above. For example, in some embodiments, one or more practice sessions may be performed prior to the beginning of training to familiarize the participant with the nature and mechanisms of the exercise. For example, in one embodiment, before training begins, the participant may perform at least one practice session comprising a specified number of trials (e.g., 5) for each of one or more practice conditions. In some embodiments, the participant may be able to invoke such practice sessions at will during the exercise, e.g., to re-familiarize the participant with the task at hand.
In some embodiments, additional trials, referred to as “eureka” trials, may be performed periodically, e.g., every 20 trials or so, comprising non-ZEST trials that are easier than the current threshold estimate—e.g. using durations that are twice the threshold. These easier trials may serve to encourage the participant to continue the exercise, and improve or maintain the participant's morale.
Thus, embodiments of the Eye Movement exercise described herein may operate to improve a participant's cognition, including, for example, frequency of saccade, minimal fixation duration (or other stimulus intensity) required to extract information from the visual scene, overall speed and accuracy of visual processing, attention, and/or memory, among others. It should be noted that the particular exercise disclosed herein is meant to be exemplary, and that other repetition-based cognitive training exercises using visual stimuli with multiple stimulus sets may be used as desired, possibly in combination. In other words, the Eye Movement exercise described herein is but one example of a cognitive training exercise using a computing system to present visual stimuli to a participant, record the participant's responses, and modify some aspect of the visual stimuli based on these responses, where these method elements are repeated in an iterative manner using multiple sets of stimuli to improve the cognitive ability of the participant, e.g., to process visual information. Note particularly that such cognitive training using a variety of such visual stimulus-based exercises, possibly in a coordinated manner, is contemplated.
Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention as defined by the appended claims. For example, various embodiments of the methods disclosed herein may be implemented by program instructions stored on a memory medium, or a plurality of memory media.
This application claims the benefit of the following U.S. Provisional Patent Applications, which are incorporated herein in their entirety for all purposes: DocketFilingNo.Serial No.Date:Title:PS.011960/750509Dec. 15, 2005HAWKEYE ASSESSMENTSSPECIFICATIONPS.022160/821935Aug. 9, 2006COMPUTER BASED TRAININGPROGRAM TO REVERSE AGERELATED DECLINES IN EYE-MOVEMENT EFFICIENCYPS.022460/822537Aug. 16, 2006COMPUTER BASED TRAININGPROGRAM TO REVERSE AGERELATED DECLINES IN EYE-MOVEMENT EFFICIENCY
| Number | Date | Country | |
|---|---|---|---|
| 60750509 | Dec 2005 | US | |
| 60821935 | Aug 2006 | US | |
| 60822537 | Aug 2006 | US |
