Steven A. Telian

Vestibular and Balance Rehabilitation Therapy

A prospective observational study of the performance of patients enrolled in an individually customized program of habituation and balance rehabilitation physical therapy was conducted from January 1988 to January 1990. Patients ranged in age from 20 to 89 years, with a wide variety of diagnoses. Two global outcome measures — posttherapy symptom response score and pretherapy and posttherapy disability score — were developed and used to judge overall patient performance. In addition, two specific indicators — one for balance performance (dynamic posturography) and one for sensitivity to rapid head movements (motion sensitivity quotient) — were used to measure performance in these two areas. Results indicate statistically significant changes before versus after therapy for both specific measures, and 80% to 85% of the patients showed a reduction in symptoms and disability score following therapy. Analysis of variance and multiple regression analysis indicate that nature of symptoms, pretherapy disability level, history of head injury, and results on dynamic posturography were the variables most predictive of therapy outcome, while age and duration of symptoms made no difference. Other variables, such as medications and site of lesion, were found to affect the length of therapy but not the outcome.

Programmatic Vestibular Rehabilitation

Although the use of vestibular exercises for patients with persistent vertigo and dysequilibrium has received some attention for many years, organized vestibular rehabilitation therapy programs have only recently been introduced. The benefits of such programs are becoming widely accepted. They typically involve a three-pronged approach: habituation exercises designed to facilitate central nervous system compensation by extinguishing pathologic responses to head motion, postural control exercises, and general conditioning activities. This article will describe the programmatic approach to vestibular rehabilitation, emphasizing selection criteria and reviewing results that may be anticipated when this treatment modality is used in a variety of patient populations.

Evaluation of Clinical Measures of Equilibrium

Objective: Evaluate the clinical utility of several simple measures of static and dynamic equilibrium in human subjects. In particular, one proposed clinical measure, the Clinical Test of Sensory Integration and Balance (CTSIB) was compared with dynamic posturography for the measurement of postural control capabilities.

Cochlear implant failures and revision.

Objective: To review cases involving implant failure and revision surgery in a large cochlear implant program. Study Design: Retrospective case series. Setting: Cochlear implant program in an academic medical center. Patients: Adults and children who underwent revision cochlear implantation (n = 58). Intervention: Diagnosis and explantation of failed cochlear implants, with subsequent reimplantation. Assessment of implant function and speech perception. Main Outcome Measures: Device type, time from implantation to revision, cause of failure, performance with original implant versus revision, number of electrodes placed, and surgical challenges related to reimplantation. Results: Forty-five patients initially implanted at this program and 13 patients implanted elsewhere underwent revision surgery. The institutional device failure rate was 3.7% and the overall revision rate was 5.1%. Reasons for implant revision included documented internal device failure (46%), scalp flap complications (17%), optimization of electrode placement (13%), unexplained deterioration of performance (12%), technology upgrade (10%), and intratemporal pathology (3%). Revision surgery typically involved only minor anatomic challenges, but five patients required circumodiolar drillout procedures to improve electrode position. Electrode insertion was equal or deeper in 53 of 58 cases. Speech perception ability decreased in only three patients. Conclusions: Management of implant failures and performance of revision surgery are becoming increasingly important in cochlear implant programs. Outcomes are generally excellent. Revision implantation is a safe and appropriate procedure that should be pursued in a timely fashion when patients experience cochlear implant failure.

Identification and Characterization of Choline Transporter-Like Protein 2, an Inner Ear Glycoprotein of 68 and 72 kDa That Is the Target of Antibody-Induced Hearing Loss

The Kresge Hearing Research Institute-3 (KHRI-3) antibody binds to a guinea pig inner ear supporting cell antigen (IESCA) and causes hearing loss. To gain insight into the mechanism of antibody-induced hearing loss, we used antibody immunoaffinity purification to isolate the IESCA, which was then sequenced by mass spectroscopy, revealing 10 guinea pig peptides identical to sequences in human choline transporter-like protein 2 (CTL2). Full-length CTL2 cDNA sequenced from guinea pig inner ear has 85.9% identity with the human cDNA. Consistent with its expression on the surface of supporting cells in the inner ear, CTL2 contains 10 predicted membrane-spanning regions with multiple N-glycosylation sites. The 68 and 72 kDa molecular forms of inner ear CTL2 are distinguished by sialic acid modification of the carbohydrate. The KHRI-3 antibody binds to an N-linked carbohydrate on CTL2 and presumably damages the organ of Corti by blocking the transporter function of this molecule. CTL2 mRNA and protein are abundantly expressed in human inner ear. Sera from patients with autoimmune hearing loss bind to guinea pig inner ear with the same pattern as CTL2 antibodies. Thus, CTL2 is a possible target of autoimmune hearing loss in humans.

Pediatric cochlear implant patient performance as a function of age at implantation.

Objective: The objective of this study was to examine the effect that age at implantation has on performance of children who received multichannel cochlear implants. Study Design: This is a retrospective study of 295 children who were broken down into 5 age groups based on age at implantation: 1–3 years, 3–5 years, 5–7 years, 7–9 years, and 9–11 years. Speech perception test scores obtained 12, 24, and 36 months postactivation were compared for the 5 groups using repeated-measures analysis of variance. Setting: This study was carried out at a tertiary academic medical center. Patients: Subjects consisted of 295 children who ranged in age from 12 months to 10 years 11 months at the time they obtained their cochlear implant. Intervention: All patients received their cochlear implant at a single implant facility. Main Outcome Measures: Performance on several speech perception tests was compared 12, 24, and 36 months postactivation. Performance was evaluated as a function of age at implantation. Results: Patients in all 5 groups demonstrated improved scores when compared with scores obtained preoperatively with hearing aids. Repeated-measures analysis of variance (ANOVA) revealed a significant group by time interaction for 3 of the 5 measures. For all three of these measures, children implanted at younger ages demonstrated greater gains in speech perception over time than children implanted at older ages. Conclusions: These results are in agreement with those of previous studies indicating that early implantation facilitates improved development of speech perception skills in profoundly deaf children.

Bilateral vestibular paresis: Diagnosis and treatment

Patients with bilateral peripheral vestibular dysfunction present a substantial diagnostic and therapeutic challenge to the otologist. Caloric irrigations that suggest bilateral weakness may mislead the clinician when considerable peripheral function remains. Rotary chair testing at several frequencies is helpful in confirming the degree of residual function and may identify patients who have a better prognosis in rehabilitation. Forty-nine patients with bilateral vestibular paresis were evaluated. The diagnosis was based on caloric responses of less than 5 degrees/sec in both ears and reduced gain on rotary chair trials. Oscillopsia occurred in the minority of patients (35%) and was rare unless severe paresis was present. Episodic vertigo occurred in 43%. All patients had abnormal posturography results, with vestibular dysfunction and severe dysfunction patterns predominating. The treatment outcomes of 22 patients who underwent vestibular rehabilitation are discussed. Prevention of bilateral vestibular paresis remains a high priority.

Hearing preservation following suboccipital removal of acoustic neuromas

Advances in the diagnosis and intraoperative management of acoustic neuromas have greatly reduced the incidence of neurologic deficits following their removal. Ninety‐three patients underwent acoustic tumor removal during a 4½‐year period, and hearing preservation was attempted in 20 cases. Hearing was preserved in 65% of the entire series, and excellent results were obtained in tumors less than 1.5 cm. No patient with a tumor greater than 1.5 cm had serviceable hearing preserved when total tumor removal was performed. Two patients, one with neurofibromatosis and one with an acoustic neuroma in an only‐hearing ear, had planned partial tumor removal with preservation of hearing. Preoperative auditory brainstem response results were not predictive of postoperative hearing preservation. Intraoperative auditory brainstem response monitoring demonstrated that loss of wave V consistently correlated with loss of hearing postoperatively, whereas persistence of wave V (with a latency prolongation not exceeding 3.00 ms) was predictive of successful hearing preservation regardless of latency increases.

Hearing preservation and facial nerve outcomes in vestibular schwannoma surgery: results using the middle cranial fossa approach.

Objective: To evaluate surgical results using the middle cranial fossa approach for hearing preservation vestibular schwannoma surgery. Study Design: Retrospective case review. Setting: Tertiary referral academic center. Patients: Seventy-three consecutive patients with vestibular schwannoma operated on using the middle cranial fossa approach between February 1999 and February 2005. Interventions: The tumors were removed via the middle cranial fossa approach with modifications to improve exposure. Standard auditory brainstem and facial nerve monitoring were used. Main Outcome Measures: Pre- and postoperative hearing measures and facial function, tumor size, and postoperative complications. Hearing status was categorized into Classes A, B, C, and D as described by the American Academy of Otolaryngology-Head and Heck Surgery “Guidelines for the Evaluation of Hearing Preservation in Acoustic Neuroma, 1995.” Results: Thirty-four patients presented with Class A hearing preoperatively. Among patients presenting with Class A hearing, a total of 27 (80%) maintained Class A or B hearing postoperatively. Of these, 21 (62%) remained in Class A, 6 (18%) deteriorated slightly to Class B, and 7 (20%) deteriorated to Class D postoperatively. Twenty-eight patients presented with Class B hearing preoperatively. Of these, 18 (64%) remained in Class B, 3 (11%) deteriorated to Class C, and 7 (25%) deteriorated to Class D. Three patients had Class C hearing preoperatively. Of these, 2 (66%) remained in Class C and 1 (33%) deteriorated to Class D. Eight patients presented in Class D and one of these improved to Class C postoperatively. Overall, 62 patients presented with useful (Class A or B) hearing and 45 (73%) remained in Class A or B. Nineteen patients had tumors larger than 10 mm in greatest dimension and had Class A or B hearing preoperatively. Of these, 11 (58%) retained Class A or B hearing postoperatively. At 4 months or greater follow-up, facial nerve outcome were excellent in 96%: House-Brackmann Grade I in 61 (85%), Grade II in 8 (11%), and Grade III in 3 (4%). There were no Grade IV, V, or VI results on final follow-up. Six (8%) patients developed cerebrospinal fluid leaks. Conclusion: By achieving excellent exposure and using meticulous microsurgical technique, it is possible to resect small vestibular schwannomas via the middle fossa approach, with preservation of hearing at excellent or preoperative levels in the majority of patients, with excellent or satisfactory facial nerve outcomes in 96% of patients.

Habituation and balance retraining therapy. A retrospective review.

The results presented indicate that rehabilitation therapy for balance disorders can be of significant benefit for a wide range of patients as a singular management tool or in combination with medical or surgical techniques. Although more investigative work is needed to adequately address the issue of customized versus generic programs, the present data begin to suggest some possible advantages to an approach individualized to each patient.