The present inventions relate to the treatment of tinnitus patients and more particularly to improved clinical methods and apparatus for treatment of mono-frequency tinnitus patients utilizing phase shift cancellation principles.
Tinnitus is defined as the perception of sound by an individual when no external sound is present, and often takes the form of a hissing, ringing, roaring, chirping or clicking sound which may be intermittent or constant. According to the American Tinnitus Association, tinnitus afflicts more than 50 million Americans, and more than 12 million of those suffer so severely from tinnitus that they seek medical attention and many cannot function normally on a day-to-day basis.
Tinnitus, often referred to as ringing in the ears, is estimated to be present in approximately 50% of the US population over 65 years of age. In general, tinnitus takes many and varied forms, which may be related to its underlying cause. Tinnitus may be caused by, or related to, such diverse factors as trauma, drugs, hearing loss, the normal aging process or other unknown causes.
Previous approaches to treating tinnitus have focused on masking the tinnitus noise experienced by patients. While previous masking techniques have been unable to alleviate the problems of tinnitus patients, significant research has been done. In reporting on studies at the Oregon Tinnitus Clinic, Jack Vernon, director of the Oregon Hearing Research Center, stated that, in patient tinnitus studies, phase and tone relationships are of obvious and critical importance in tone masking of tinnitus. Vernon goes on to observe that one cannot repress the idea of canceling tinnitus by a proper phase adjustment of the external tone used in masking.
In commenting on Wegel's earlier tinnitus treatment findings that a slight mistuning of a masking external tone produced a beat-like sensation with the tinnitus sound, Vernon reported that, in a 100 patient study, he was able to detect a slight beat-like sensation in only four instances. Vernon therefore concluded that the beat-like sensation found by Wegel was most probably due to octave confusion resulting from Wegel not using a single pure tone, but rather a narrow band of noise. In conclusion, Vernon observed that phase manipulation justifies further patient studies as a masking parameter for tonal tinnitus treatments. Vernon's report on possible phase manipulation for treating tinnitus patients remained unchanged from its original publication in 1991 and as included in the 1997 edition of Shulman's treatise entitled “Tinnitus Diagnosis and Treatment.”
In his above-referenced U.S. Application, Dr. Choy reports on favorable patient data from blind clinical studies utilizing a 180-degree phase shift of an externally generated tinnitus tone. More than 79% of patients studied reported either elimination of, or substantial reduction in the level of, tinnitus noise.
Neither current medical procedures nor electronic or sonic instrumentation permit or facilitate an objective determination of either the frequency or amplitude of the tinnitus noise a patient experiences. It is also not possible to subjectively determine an instantaneous phase of a point on a patient's virtual mono-frequency tinnitus tone.
This current state of tinnitus treatment has been bothersome for the tinnitus patient because the current state of medical knowledge and acoustic/electronics instrumentation does not yet permit one to objectively determine at what point on a patient's virtual endogenous tinnitus sound wave tinnitus tone (sine wave) an exogenous phase-shifted sine wave would be inserted in an attempt to cancel the patient's virtual tinnitus noise.
In one of many possible embodiments of the present invention, reciprocal noise cancellation of a patient's mono-frequency tinnitus tone is achieved utilizing an externally generated tone which is subjectively defined by a mono-frequency tinnitus patient to match his/her tinnitus tone in frequency and amplitude. In accordance with one aspect of applicant's novel apparatus and process, an externally generated sound wave, selectively designated by subjective observations of a patient to match the patient's tinnitus tone is first applied to the tinnitus patient via earphones or a speaker system. Then, the same externally generated sound wave is sequentially phase shifted through a plurality of angularly shifted sequence steps to shift or slide the external sound wave through at least a 180 degree phase shift of the generated signal as it is applied to the patient to achieve in one of such shifted steps a reciprocal canceling relationship with the patient's tinnitus tone. The tinnitus treatment sequence of an externally generated sound wave and then the phase shifted externally generated tone achieve cancellation of the tinnitus tone of the patient as the sequential steps of the generated tone in effect slide across the tinnitus sound wave resulting in cancellation of the tinnitus tone.
Applicant's inventive apparatus and process may be embodied in a portable self-treatment memory device which includes a sequence of recorded tinnitus treatment tone segments, e.g., externally generated tone, and the sequential phase shift steps being recorded either during a patient's clinical treatment or later based upon a patient's clinical data. By replaying the sequential phase shifted segments of the patient treatment process, a patient may utilize the previously recorded sequences in a patient self-treatment process.
The accompanying drawings illustrate various embodiments of the present invention and are a part of the specification. The illustrated embodiments are merely examples of the present invention and do not limit the scope of the invention.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
To remedy the current deficiencies in diagnosing and treating tinnitus patients, and more particularly mono-frequency (single tone) tinnitus, applicant has developed a new, more efficient phase cancellation treatment process and apparatus that overcomes many of the shortcomings in the prior art. There is a long-felt need for an effective treatment for mono-frequency tinnitus patients to substantially reduce, relieve or eliminate the often substantially debilitating condition of tonal tinnitus.
Referring now to
Sound generator 10 has a plurality of adjustable knobs, 18 and 20, and an output terminal 24. As will be hereinafter explained in further detail particularly with respect to
This subjective “sound-typing” is preferably repeated a plurality of times on a blind basis, i.e. the patient cannot see the oscilloscope 14. A barrier 36 may be placed between the patient 11 and the oscilloscope 14 and the sound generator 10. Additionally, either this is no display on the sound generator 10 that a patient 11 can observe, or any such display is masked and concealed from the patient 11. In this manner, if the patient is able to subjectively select roughly the same parameters a number of times to match his or her perceived tinnitus noise with the sound generator 10, there can be confidence that the output of the sound generator 10 accurately approximates the tinnitus noise experienced by the patient 11.
The subjective sound typing data for each of the self-typing steps is preferably recorded by an attending audiologist or physician. Additionally, the output of the first sound generator 10 can be matched by adjusting a second sound generator 16 to produce the same output. The outputs of the first sound generator 10 and the second sound generator 16 can be compared on the oscilloscope 14 to ensure they are the same. The output of the second sound generator 16 can be used, as will be described below, to prepare a treatment recording for the patient 11.
The principles of sound wave cancellation operate by superimposing, e.g. summing, a second sine wave having the same frequency and amplitude, as the first sine wave with a phase shift of 180 degrees. Sound wave cancellation is well understood in the electrical and measurement arts and is utilized in many technical fields including audiology, mechanics and electronics generally. With mono-frequency tinnitus, the patient should be able to adjust the output of the first sound generator 10 to approximate the tinnitus noise that he or she hears.
The method of accomplishing the phase shift cancellation effect of summing two waves of the same frequency and amplitude, but without any knowledge of the phase relationship of the first wave to the second wave relative to a common point, can be illustrated as follows. Sound generator 10 is set to a first tone having a frequency of f1 and an amplitude of A (for example in milli-volts as displayed on sound generator 10) and connected to the first input of multi-beam oscilloscope 14. A second generator 16 is also set to the same tone with a like amplitude and the output is connected as a second input to oscilloscope 14.
With reference to
It is well understood in the field of audiology that humans and animals can determine, to a considerable degree of precision, the direction of a sound wave remote from them and to some extent can also estimate the distance of a sound source. Numerous experiments in the field of audiology have attempted to analyze the mechanics by which so-called binaural localization is accomplished in humans and animals. There are two primary factors which assist one in determining the direction of an arriving sound: (1) relative intensity in the hearer's two ears and (2) the difference in phase between the ears or, for a sinusoidal tone, the difference in phase between the sound waves arriving at the right and left ear of the hearer respectively. Thus, it is clear that a human or animal auditory system can distinguish phase shifts of complex sound generally and for pure or mono-frequency tones specifically. This type of auditory analysis is frequency dependent and, for frequencies above 1 Khz, most observers tend to determine the direction of a sound source from the side of the ear receiving the louder sound. Thus in general, it appears that auditory localization by phase difference is most definite for a band of frequencies in the order of a few kilohertz. As discussed hereinafter, with reference to
Referring again to
As shown in
Switch 32, as illustrated, applies the shifted output of the sound generator 10 to the headphones 12. The successively phase-shifted increments of sine wave tone from generator 10, as explained above, are successively generated relative to f1, as illustrated in
Referring now to
Patient Sine Wave:
P(t)=P0 sin 2πft
Input Sine Wave from Generator:
I(t)=I0 sin(2πft−θ)
Sum of P(t) and I(t):
S(t)=P(t)+I(t)=(P0 sin 2πft)+I0 sin(2πft−θ)
Thus,
A=2P0 cos (½θ);
Referring now to
The tinnitus treatment tone may be displayed on a monitor or oscilloscope 14-4 to enable the clinician to monitor the shift from the initial tinnitus tone f to the shifted increments of the tinnitus treatment tone fm as shown in
Referring now to
Referring now to
Referring now to
Data from step 1 is utilized in step 2 by the attending clinician or physician to generate an appropriate external sine wave treatment tone substantially equal to the patient's tinnitus tone. Then, the generated treatment tone is time-shifted through a plurality of successive substantially equal predetermined step increments totaling 180 degrees whereby the generated wave form is brought through such sequential phase shifting into a series of canceling and eventually into a reciprocal canceling relationship with the patient's tinnitus tone during a treatment period or zone, as will be further described in connection with
In step 3, the tinnitus patient, after completing step 2, maybe subjected to a PET or Functional MRI Brain Scan to objectively assess the patient's current tinnitus activity in order to objectively quantify the elimination or degree of substantial reduction in the amplitude of the patient's tinnitus tone after receiving applicant's phase shift cancellation treatments. These procedures are routinely conducted as part of many on going clinical studies. Recently Danish, Swedish and French investigators have confirmed positive PET Brain Scans in the auditory cortex of tinnitus patients. It should be noted that the Brain Scans of tinnitus patients may be conducted before, during or some time after the phase shift tinnitus treatment has been administered to gain additional objective patient treatment data for tinnitus patients.
Referring now to
Referring now to
As shown in
As is well known in the medical arts, a tinnitus condition in humans may have many different forms and many, very different causes. For a brief survey of medical tinnitus treatment literature, reference may be had to the above cross-referenced U.S. application Ser. No. 10/083,088. While there is no known “cure” for tinnitus, for those individuals who suffer substantial medical disability from tinnitus any, even temporary, relief can be very significant.
In the above cross-referenced application, application Ser. No. 10/083,088, patient clinical results from a 28 patient blind tinnitus single step 180-degree phase shift treatment protocol study are reported. In that study, seven patients (25%) experienced excellent results achieving more than 90% reduction in tinnitus loudness. 15 patients (more than 54%) experienced either “Very Good” or “Good” results having achieved temporary relief of at least a 50% reduction in tinnitus loudness. It is believed that utilizing the above-described six-degree phase shift segments protocol, for example, with each segment having a duration of at least one minute will achieve substantially improved results over the techniques described in application Ser. No. 10/083,088.
Referring now to
Block 70 illustrates the screening process for determining whether a tinnitus patient is a good candidate for the mono-frequency phase shift treatment. As stated above, medical science cannot in most instances identify the exact or likely cause of a patient's tinnitus condition nor describe the precise mechanism or mechanisms causing a particular patient's tinnitus condition.
As illustrated in block 72, if a patient exhibits mono-frequency tinnitus which, for example is not related to drug use, then the patient is asked to self type his/her tinnitus tone utilizing an externally generated tone from a sound generator wherein the externally generated tone is manipulated to match the subjectively determined patient's tinnitus tone. As stated above, the patient's self-typing process is preferably repeated several times, on a blind basis, to ensure accuracy. Thereafter, as illustrated in block 74, the patient's subjectively determined treatment tone is incrementally phase shifted through at least a full 180 degree shift in a single treatment session to thereby bring the externally generated tone into a reciprocal, wave-canceling relationship with the patient's tinnitus tone.
Following the phase shift tinnitus treatment protocol as illustrated in block 76, the patient maybe subjected to a PET or MRI Brain Scan procedure to objectively determine the effect of the phase shift treatment to reduce, minimize or eliminate the brain activity in the auditory cortex normally associated with a patient's tinnitus condition. It should be noted that, as shown in
As discussed above, there is currently no medical treatment for tinnitus which “cures” a patient's tinnitus condition permanently. Thus, while a particular mono-frequency tinnitus patient experiences substantial reduction or temporary elimination of his/her tinnitus condition following an application of applicant's improved phase shift tinnitus treatment, the residual effect generally lasts only for a limited time, on the order of hours or days, or as long as ten days in a few instances. Thus, the use of the objective brain scan data may assist the clinician as shown in block 80, to classify a patient self-treatment status. As described above in connection with
While a number of alternative embodiments of applicant's novel apparatus and process for the treatment of tinnitus have been described, those skilled in the medical and auditory arts will recognize that the described embodiments are illustrative and additional changes or modifications of the described preferred embodiments may be made without departing from the scope of the present inventions embodied in the following claims.
The preceding description has been presented only to illustrate and describe embodiments of invention. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be defined by the following claims.
This application claims the benefit of the earlier filing date of U.S. Provisional Application No. 60/340,271, filed Dec. 18, 2001 and further relates to U.S. application Ser. No. 10/083,088 filed Mar. 1, 2002. The specification and disclosure of both of these related Applications are incorporated herein in their entirety by this reference.
Number | Date | Country | |
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60340271 | Dec 2001 | US |
Number | Date | Country | |
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Parent | 10319281 | Dec 2002 | US |
Child | 10979452 | Nov 2004 | US |