Research in the auditory and vestibular systems. The recommendations of the National Institute on Deafness and Other Communication Disorders National Strategic Research Plan.

Promising fundamental research opportunities identified by the National Strategic Research Plan of the National Institute on Deafness and Other Communication Disorders include encoding of sound and gravitational/acceleration force by the inner ear, processing complex signals in the central nervous system, the molecular and cellular mechanisms responsible for hair cell motility, mechanoelectric transduction, homeostasis and metabolism of the inner ear, synaptic transmission, hair cell regeneration, plasticity and otoacoustic emissions. Clinical research opportunities include the molecular genetics of hereditary hearing impairment, the etiology of sensorineural hearing loss, environmental ototoxicity, the elucidation of tinnitus, the development of vaccines against otitis media, pharmacotherapy, rehabilitation for hearing loss and deafness with hearing aids and cochlear implants and physical therapy rehabilitation for vestibular disorders.

Successful treatment of selected cases of abductor spasmodic dysphonia using botulinum toxin injection.

Ten patients with abductor spasmodic dysphonia, who exhibited spasmodic bursts and heightened activity of the cricothyroid muscle during speech, were selected for participation. Between 5 and 20 U of botulinum toxin type A were injected into both right and left cricothyroid muscles. Six patients benefited substantially, whereas four did not. Acoustic analyses of voice patterns showed similar changes to the clinical impressions. Significant group improvements were found in sentence duration while selected patients improved in the proportion of their speech that was voiced and the duration of their voiceless consonants. Those patients with abductor spasmodic dysphonia and other muscle abnormalities in addition to the cricothyroid and with constant breathiness did not benefit.

Spasmodic dysphonia: botulinum toxin injection after recurrent nerve surgery.

The purpose of this study was to determine if botulinum toxin injections into the thyroarytenoid muscle would reduce symptoms in adductor spasmodic dysphonic patients who had experienced symptom recurrence after recurrent laryngeal nerve surgery. Five patients were seen between 3 to 10 years after surgery with a return of speech symptoms and persistent unilateral vocal fold paralysis. Before injection, comparisons with controls on spectrographic measures of pitch and voice breaks, aperiodicity, and sentence length demonstrated significant symptoms of spasmodic dysphonia (p less than or equal to 0.02). Electromyographic measures demonstrated equal levels of thyroarytenoid muscle activation on the operated and non-operated sides with bipolar needle electrodes, and heightened activity in both muscles relative to normal. Therefore, symptom return was associated with thyroarytenoid innervation after recurrent nerve surgery. In all patients, the thyroarytenoid muscle on the side operated on was injected with type A botulinum toxin. In two patients, toxin was also injected on the side not operated on. Significant (p less than or equal to 0.002) reductions in all speech symptoms occurred after injection. Electromyographic measures demonstrated significant reductions in the percent activation levels of both the injected muscle and noninjected muscles (p less than or equal to 0.01). Botulinum toxin injections were an effective treatment of post-surgical symptom recurrence in adductor spasmodic dysphonia.

A new surface electrode for recording from the posterior cricoarytenoid muscle.

A new pharyngeal surface electrode for recording posterior cricoarytenoid muscle activity through the hypopharyngeal mucosa has been evaluated. The electrode was passed through one nasal passage into the hypopharynx. Correct electrode location was verified by increased activity during inhalation, with decreased activity during phonation. The procedure was evaluated in 45 subjects, 10 normal speakers and 35 patients with dysphonia. Accurate recordings were obtained in 25 subjects (56%). Problems encountered were lack of pharyngeal descent, electrode dysfunction, and signal interference due to phonatory vibration or interarytenoid activity. Signal validity was evaluated in four normal speakers with accurate electrode placement. Significant (p less than or equal to 0.001) increases in PCA activity occurred during tasks requiring vocal fold abduction. The electrode proved to be a useful, noninvasive clinical tool for recording PCA activity in some patients.

Effects of botulinum toxin injections on speech in adductor spasmodic dysphonia.

Adductor spasmodic dysphonia involves an overadduction of the vocal folds during speech causing uncontrolled voice and pitch breaks and slow, effortful speech. The disorder is resistant to speech therapy and often recurs following initial benefit from unilateral recurrent laryngeal nerve resection. Botulinum toxin injections into multiple sites of the thyroarytenoid muscle on one side were performed in 16 patients. Speech was recorded prior to injection and three times post-injection. Symptoms were measured by two examiners from speech spectrograms without knowledge of speaker identity or recording session. Significant (p less than or equal to 0.03) reductions in pitch and voice breaks, phonatory aperiodicity, and sentence time occurred only when injections resulted in unilateral vocal fold paralysis. Symptoms returned with the restoration of vocal fold movement, 3 months later. Reduction in speed of swallowing without aspiration was reported in 80% of cases. Although speech volume was reduced, there were no instances of aphonia.

Hypertrophy of the tensor tympani muscle presenting as a middle ear mass.

A wide variety of benign and malignant middle ear masses have been reported in the literature. We present here an example of a previously unreported type of lesion, a case of hypertrophy of striated muscle, probably the tensor tympani muscle, presenting as a middle ear mass in a 17-year-old male. Clinical evaluation revealed a marked conductive hearing loss and eustachian tube obstruction.

Procedures for the selection of spastic dysphonia patients for recurrent laryngeal nerve section.

Patients with spastic dysphonia were studied to identify the characteristics of patients benefiting from recurrent laryngeal nerve (RLN) surgery. Studies included laryngeal video recordings made during speech, measures of frequency and amplitude variations during extended phonation, the effects of altered auditory feedback on dysfluencies, and temporary unilateral RLN block. Two patients had vocal fold adductor spasms during connected speech, had increased acoustic phonatory tremor in frequency, were not benefited by altered auditory feedback, and responded favorably to nerve block. Subsequent RLN section improved the speech of both patients. Other patients had speech blocks, repetitions and prolongations, vocal fold tremors during phonation, reduced dysfluencies during altered auditory feedback, and were not benefited by temporary nerve block. Two subtypes of spastic dysphonic patients are proposed.

Research in otolaryngology: NIH support and other considerations.

The National Institutes of Health continue to provide support for a major portion of biomedical research in this country. Research serves as the keystone to the continued health of Otolaryngology, but there are clear indications that otolaryngologists' direct involvement in research is diminishing at a dangerous pace. Some of the causes of this problem are identified. Solutions include, first and foremost, more general recognition of the importance to the speciality of biomedical research; currently available mechanisms offered by the National Institute of Neurological and Communicative Disorders and Stroke for the support of investigator training might be utilized more extensively and collaborative research between clinician and basic science investigators should be encouraged.

Tympanostomy tubes: the conservative approach.

The clear advantage accruing from the use of tympanostomy tubes in the treatment of otitis media with effusion is immediate improvement in hearing; there are also disadvantages entailed, such as scarring of the drum risk of continuing otorrhea and interference with the patient's normal physical activities. All possible forms of medical treatment should be exhausted (antihistamine decongestants, politzerization) before resorting to tympanostomy tubes. There is a small group of children with severe chronic nasal obstruction and otitis media with effusion for whom adenoidectomy is likely to be required.

The Ear, Nose, and Throat Devices Classification Panel of the Food And Drug Administration.

The passage into law in 1976 of the Medical Device Amendments authorized the FDA to regulate the safety and efficacy of medical devices. The effects of this regulation are contrasted with the mode of entry of medical devices onto the market prior to 1976. The structure and operation of Ear, Nose, and Throat Devices Classification Panel is described briefly. Continued input from otolaryngologists and allied professionals is encouraged.

The evaluation of peripheral auditory function in infants and children.

The technique of electrocochleography described, although invasive, has proved to be innocuous in our experience. It provides precise information concerning peripheral auditory activity in response to sound stimulation at frequencies across the audible range. The most valuable application of the technique in clinical practice is in testing the hearing of infants and children who are too young to test by standard behavioral audiometric techniques, and in testing the hearing of children with behavioral problems or mental retardation;

Hereditary progressive sensorineural deafness.

Progressive sensorineural hearing losses found in seven members of three families are presented. Genetic transmission patterns in the study appeared to be autosomal dominant in two families and recessive in one family. The common audiological features of these cases include bilaterally symmetrical audiometric configuration and fairly good speech discrimination. The hearing losses of most of the cases appeared to begin at high frequencies progressing later to involve lower frequencies. The main histopathological changes in the temporal bones of one of the cases were degeneration of the organ of Corti and of the spiral ganglion in the lower cochlear coils and cystic degeneration of the stria vascularis in the upper coils.

Basis and some diagnostic implications of electrocochleography.

Electrocochleography (ECoG) involves the recording of electrical responses to sound from the vicinity of the cochlea. The technique, as we practice it, utilizes a trans-tympanic recording needle situated on the promontory of the middle ear. Filtered clicks in the frequency range between 500 and 8,000 Hz are presented to the ear under test at a rate of 10/sec. Repetitive clicks of a given frequency are first presented at high intensity and the responses summed (averaged) in a computer. The click is systematically lowered in intensity, and an average is collected at each level until the normal dynamic range of hearing has been explored. Two major electrical indices are present in the recording: these are 1. the whole-nerve action potential (AP) derived from the first-order auditory neurons, and 2. the cochlear microphonic (CM) derived from the hair cells. Inspection of the whole nerve AP as intensity is lowered allows the estimation of the response threshold, which correlates well with behavioral threshold. Inspection of the relation between the CM and the AP allows qualitative differentiation to be made between pathology arising in the hair cell (sensory) and in the nerve (neural).

Human whole-nerve response to clicks of various frequency.

The averaged VIIIth nerve response to third-octave clicks at 500, 2000 and 8000 Hz was recorded from the promontory of 4 normal-hearing young adults. As click frequency is lowered, the N, latency increases in a manner consistent with the changes in velocity of the cochlear traveling wave. This finding suggests that clicks of different spectral content stimulate different regions of the basilar membrane. N amplitude shows a general increase with frequency; this observation appears related to the increased synchrony of neural firing that results from the higher velocity of the traveling wave in the more basal portions of the cochlea.

Physical and auditory specifications of third-octave clicks.

Physical: measurements of third-octave clicks (produced by ringing a commercial third-octave filter having a rejection rate of 50 dB in the first octave) show that waveform and spectral shape of the clicks remain the same through the range of audiometric frequencies. Auditory: relations between click and tonal thresholds are developed by (a) comparing click and tone thresholds at a repetition rate of 5/sec and (b) determining changes in click threshold for a range of repetition rates between 1 and 10/sec. Tonal thresholds are about 10 dB more sensitive at the 5/sec rate; a click repetition of 10/sec lowers the threshold, reducing the difference between tone and click audibility, while a repetition rate of 1/sec raises click threshold and increases the difference.