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Biomedical subjects

P R Kileny

Publications and source records attributed to P R Kileny.

At least 19 recordsLinked to original sources
PubMed1992

Tinnitus suppression following cochlear implantation. A multifactorial investigation.

The effects of cochlear implant on loudness, annoyance, daily duration, location, and residual inhibition of tinnitus were evaluated by a closed-ended, quantifiable questionnaire in 33 postlingually deafened patients who had received implants at the University of Michigan, Ann Arbor, between 1986 and 1990. Preoperative tinnitus was present in 85% of patients. A statistical comparison of preoperative vs postoperative loudness and annoyance indicated a significant reduction in both of these complaints postoperatively. Loudness and annoyance were significantly correlated, both preoperatively and postoperatively. Fifteen patients (54%) with preoperative tinnitus demonstrated a loudness decrease of 30% or more; 43% demonstrated an annoyance decrease of 30% or more; and 48% demonstrated a decrease of 30% or more in daily tinnitus duration. Patients who experienced a loudness or annoyance decrease of 30% or more after implantation demonstrated significantly higher preoperative levels of these complaints, suggesting that degree of tinnitus reduction after implantation may be related to preoperative loudness and annoyance levels. Contralateral tinnitus suppression was reported by 42% of patients. Residual inhibition ranging from 60 seconds to several hours was reported by 50% of patients, predominantly in the ear with the implant. Age, gender, cause of hearing loss, duration of tinnitus, cochlear implant usage, and time after implantation were not predictive of tinnitus suppression. Overall, the majority of the patients (74%) thought that their cochlear implant was helpful in tinnitus suppression, especially in the ear with the implant. Contralateral residual inhibition and tinnitus suppression suggest a central mechanism contributing to these phenomena.

Adult↗
PubMed1992

A comparison of round-window and transtympanic promontory electric stimulation in cochlear implant candidates.

We compared within-subjects electrical thresholds and dynamic ranges obtained with direct round-window and transtympanic promontory stimulation carried out preoperatively in 12 patients who were candidates for a cochlear implant. Square waves with frequencies of 50, 100, 200, and 400 Hz were delivered in a 50% duty cycle to both sites in each patient. With the exception of threshold at 50 Hz (promontory thresholds were lower than round-window thresholds), there were no statistically significant differences for either thresholds or dynamic ranges between the two sites of stimulation. There was a general trend for round-window thresholds to be lower and dynamic ranges larger, especially for the higher frequencies of stimulation. Mean threshold slopes for the two sites of stimulation were nearly identical.

Adult↗
PubMed1992

Prognostic value of evoked and standard electromyography in acute facial paralysis.

Ninety-one patients with idiopathic (n = 62) and traumatic (n = 29) facial paralyses were available for evaluation at least 1 year after the onset of paralysis. In nine cases of idiopathic paralysis and in 12 cases of traumatic paralysis, total intratemporal nerve decompression was performed. The remaining patients were treated with steroids alone. All patients underwent evoked electromyography (EEMG) testing within 2 weeks of the onset of paralysis. Facial nerve recovery was graded using the House-Brackmann facial nerve recovery scale. Subjects were grouped according to maximal decline of compound muscle action potential (CAP), as determined by EEMG, and by level of recovery 1 year after onset of paralysis. Among patients who did not undergo surgical decompression of the facial nerve, incomplete clinical recovery (grade III or higher) was significantly associated with CAP decline of greater than 90% (p less than 0.05) for idiopathic paralysis. In contrast, there was no significant association between CAP decline of greater than 90% and clinical outcome in traumatic paralysis. These findings support previous reports of the prognostic value of EEMG in idiopathic facial paralysis, but suggest that this test may have less predictive value in the evaluation of facial paralysis as a result of trauma.

Action Potentials↗
PubMed1992

Auditory performance of children with cochlear ossification and partial implant insertion.

The management of the profoundly deaf child with a cochlear implant poses a special challenge, particularly when total ossification of the cochlea is present. In this setting, insertion of an electrode array into a child's cochlea is often difficult. Our experience supports the feasibility of partial insertion of a multichannel implant into the basal turn of an ossified cochlea. Five children with ossified cochleae who had undergone partial implantation of a multichannel electrode were compared with the performance of matched controls who had full insertion of multichannel implants. No dramatic differences were detected during a 6- to 18-month follow-up period on selected test measures. These preliminary results suggest that active electrode number may exert a limited effect on performance with a cochlear implant. Drilling out the basal turn of an ossified cochlea in conjunction with partial insertion of a multichannel implant appears to be an acceptable surgical and rehabilitational alternative for placement of a cochlear implant prosthesis in children with complete cochlear ossification.

Adolescent↗
PubMed1992

Devices for the hearing impaired.

Hearing loss can result in significant communicative and social dysfunction. Various methods of sound amplification are available for the hearing impaired. Hearing aids are becoming more technologically sophisticated, more cosmetically appealing and more commonly used. The choice of hearing aid must be individualized and depends on several factors, including the type of hearing loss, the cost of the device, the patient's work environment, motivation and vanity, and the degree of difficulty in using the hearing aid. Devices are also available to help hearing-impaired persons in specific situations where hearing aids may not be necessary. The cochlear implant is a relatively new device for use in the profoundly hearing impaired.

Cochlear Implants↗
PubMed1992

Effects of channel number and place of stimulation on performance with the Cochlear Corporation multichannel implant.

The effects of active channel number and place of stimulation on auditory-only performance with the Cochlear Corporation multichannel cochlear implant were investigated in seven subjects. A balanced crossover design was employed; subjects were initially programmed with either 10 basal or the full complement of 20 to 21 active electrodes. Following a 6-month period with the initial coding strategy, subjects were programmed with the alternate configuration, which they used for an additional 6 months. Auditory-only performance on suprasegmental, phoneme (vowel and consonant) open- and closed-set speech recognition was compared between the two electrode configurations. Additionally, performance with the first configuration and performance with the second configuration 3 days following programming were also compared. While a trend for increased scores was noted with 20 electrodes, especially with open-set speech recognition tasks, none of the differences between the two configurations reached statistical significance, as indicated by a Wilcoxon test. A comparison of performance at the end of the first 6-month period and 3 days following programming with the second configuration revealed a trend for reduced scores, especially on vowel tests. Overall, our results indicate that the feature extraction coding strategy associated with the Cochlear Corporation device allows patients to function well with only 10 basal electrodes and that speech recognition is only mildly affected initially when patients are programmed with a different encoding strategy.

Acoustic Stimulation↗
PubMed1991

Arytenoid subluxation: diagnosis and treatment.

Both arytenoid subluxation and recurrent laryngeal nerve paralysis (RLNP) may result from injury to the larynx, and they may be difficult to distinguish clinically. A patient with arytenoid subluxation who was initially believed to have RLNP was treated with medialization laryngoplasty 1 year after the injury. Preoperative magnetic resonance imaging and computed tomography effectively demonstrated the cricoarytenoid subluxation, which was confirmed by intraoperative electromyography (EMG) showing normal electrical activity in the thyroarytenoid muscle. Photographs from preoperative fiberoptic laryngoscopy are presented to identify the appearance of arytenoid subluxation. Computed tomographic findings and photographs from laryngoscopy of two patients with RLNP documented by intraoperative EMG evaluation are presented to help distinguish the clinical appearance of this disorder from arytenoid subluxation. An integrated approach to the diagnosis and treatment of arytenoid subluxation is presented.

Adult↗
PubMed1991

Effects of preoperative electrical stimulability and historical factors on performance with multichannel cochlear implant.

We investigated the relationship between results of preoperative transtympanic electrical promontory stimulation, duration of deafness, postoperative implanted psychophysical results, and postoperative speech and speech sound recognition as indicated by a battery of five tests. Our subjects were 10 patients implanted with the Cochlear Corporation multielectrode implant, 1 year postimplantation, with a minimum of 17 active electrodes programmed in the bipolar + 1 mode. The results indicated that preoperative promontory thresholds, the slope of the threshold function, and the duration of auditory deprivation are excellent predictors of postoperative speech and speech sound recognition in the auditory (processor alone) mode. These results have significant implications for patient selection and counseling.

Adolescent↗
PubMed1991

Tinnitus as a function of duration and etiology: counselling implications.

Based on the data of 528 tinnitus patients, information is presented concerning: (a) conditions and/or activities that affect tinnitus severity, (b) tinnitus symptoms as a function of etiology, and (c) changes in tinnitus symptoms as a function of time since onset. The four most common conditions and/or activities that reduce tinnitus severity were sleep, listening to TV/radio, being in noise, or being in quiet. Many conditions and/or activities increased tinnitus severity. The most common detrimental activities and/or conditions were noise exposure, being in a quiet place, emotional stress, loss of sleep, and physical exhaustion. Results also revealed that tinnitus loudness and severity increased as a function of years since onset. However, tinnitus pitch tended to remain stable. Meniere's patients experienced more annoyance, depression, and interference with sleep and also reported louder tinnitus than other etiologies. Tinnitus counselling should include: (a) informing patients that it is unlikely tinnitus annoyance will change dramatically, (b) alerting patients to the usefulness of tinnitus self-help groups, (c) helping patients to minimize time spent in activities and/or conditions where tinnitus severity is increased and to maximize time in activities and/or conditions where tinnitus severity is decreased, and (d) stressing the avoidance of noise exposure because of the relationship between noise-induced hearing loss and tinnitus.

Adolescent↗
PubMed1991

Electrical stimulation of the auditory system after labyrinthectomy.

For many years labyrinthectomy has been used as a reliable surgical treatment for patients with unilateral nonserviceable hearing associated with episodic vertigo. In view of the rehabilitative potential of the cochlear implant, the role of labyrinthectomy has been questioned because of a concern to preserve structures of the auditory periphery. However, recent reports demonstrate substantial survival of spiral ganglion cells after labyrinthectomy, suggesting that such patients might be candidates for rehabilitation with cochlear implants if necessary. To address this question from a physiologic approach, we investigated the electrical stimulability of the operated ear in patients who underwent transmastoid labyrinthectomy for the management of vertigo. Ten patients were studied intraoperatively with electrically evoked middle latency response (MLR) potentials. Six of these patients were studied between 3 and 15 months postoperatively via transtympanic stimulation. Postoperatively all patients demonstrated an excitable auditory periphery and behavioral thresholds were similar to intraoperative electrophysiologic thresholds for the same stimuli. These results suggest the persistence of excitable auditory neural elements following labyrinthectomy.

Adult↗
PubMed1991

Cochlear implants in children.

The resources and areas of expertise necessary to establish and maintain a successful children's cochlear implant program is discussed. Insights based on experience with a pediatric patient population are presented.

Adolescent↗
PubMed1991

Use of electrophysiologic measures in the management of children with cochlear implants: brainstem, middle latency, and cognitive (P300) responses.

The introduction of evoked potential techniques into standard clinical practice has revolutionized the early detection and diagnosis of hearing impairment in infants and young children. Therefore, it should come as no surprise that the same expectations exist relative to the evaluation of the electrical stimulability of the auditory system in the youngest cochlear implant patient population. At this time, special problems related to the recording of electrophysiologic responses evoked by electrical stimulation, such as response contamination by the stimulus artifact and the recognition of stimulus spread to other than the target system, still await resolution. Ideally, one would like to be able to determine preoperatively the extent and pattern of neural survival. One would also like to be able to use electrophysiologic measures to monitor implanted stimulability and as an aid to processor calibration, programming, rehabilitation, and training. The electric ABR (EABR) may be used in both pre- and postoperative applications in children to determine stimulability and implant stability. The electric MLR (EMLR), used successfully in adults and animal models, in not a suitable response in young children, due to maturational considerations. Cognitive endogenous evoked potentials (P300) have been used successfully postoperatively with adults in this laboratory and are currently being investigated in implanted children. This paper discusses current applications of electrically evoked auditory potentials in our cochlear implant program.

Adolescent↗
PubMed1990

Effect of anesthesia on acoustically evoked middle latency response in guinea pigs.

Increased recent interest in the middle latency response (MLR) has necessitated a clarification of the possible effects of anesthesia on the response. Our study was designed to examine the changes, in the guinea pig MLR, which occurred during anesthesia with ketamine, xylazine or both ketamine and xylazine. Under anesthesia the response remained present and the threshold remained stable. After anesthesia, significant changes in amplitude, latency, and general morphology of the waveform took place, however these were consistent and predictable. For studies requiring the MLR, it is best to avoid anesthetic agents. However, with care the MLR can be used as a reliable measure of auditory system sensitivity under anesthesia.

Acoustic Stimulation↗
PubMed1990

Asymmetric brain stem auditory evoked responses in infants treated with extracorporeal membrane oxygenation.

Brain stem auditory evoked responses (BAERs) were obtained in 25 infants who received extracorporeal membrane oxygenation (ECMO) for severe respiratory failure. Tracings were obtained by means of a Nicolet CA-2000 averager, using a conventional paradigm. The presence or absence of replicated responses at 35 and 75 dB nHL were recorded for each ear. Interpeak latencies I-III, III-V, and I-V were measured and differences between right and left ears were compared, using a matched pair t-test. Wave III-V latencies were longer on the left than right (p less than 0.05), but no significant right-left differences for latencies I-III were noted. Sixteen percent of the infants failed hearing sensitivity criteria, 45% (10/23) had prolonged I-V latencies. At follow-up (age 4 to 12 months) 6/10 infants with prolonged I-V latencies had additional neurologic abnormalities. In this population left ear III-V latencies are prolonged versus right, and the incidence of abnormal BAERs is high. Relative prolongation of left ear III-V latencies (generated from the right brain stem) may be result of right carotid artery and/or jugular vein ligation for ECMO, and abnormal I-V latencies prognosticate future neurologic abnormalities in this population.

Brain Diseases↗
PubMed1990

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 41/2-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.

Audiometry, Evoked Response↗
PubMed1989

Middle-latency responses. I. Electrical and acoustic excitation.

The electrically evoked auditory brain-stem response has been used in the past to assess auditory system function with regard to cochlear prosthesis application. The brief latency of the response makes it susceptible to electrical artifact contamination, and waveform identification is often difficult. As a possible alternative for a noninvasive measure of system excitability, the middle-latency response (MLR), elicited by electrical stimulation, was investigated. Middle-latency responses were recorded in response to acoustic and round-window electrical stimulation in albino guinea pigs. Acoustic and electrically evoked MLR waveforms were similar, as were their respective latency/intensity functions. Amplitude/intensity functions for the electric MLR showed greater variability than acoustically evoked MLR functions. The electric MLR is readily evoked and relatively insensitive to electrical artifact in the guinea pig. It is potentially a useful tool in assessing the integrity of auditory pathways and consequently in the development of diagnostic tests for cochlear implant candidates.

Acoustic Stimulation↗
PubMed1989

Middle-latency responses. II. Variation among stimulation sites.

We investigated the relationship between thresholds of the electrically evoked auditory brain-stem response (EABR) and the electrically evoked middle-latency response (EMLR), and the variation in EMLR thresholds and dynamic ranges with site of stimulation. The EABRs and EMLRs were recorded in albino guinea pigs in response to electrical stimulation at the round window, promontory, scala tympani, and modiolus. The EABR and EMLR thresholds were similar. There was no significant difference between thresholds for round-window and scala tympani stimulation. Amplitude/intensity functions for the EMLR differed with site of stimulation. The EMLR seems to be comparable with the EABR for assessing the electrical excitability of the auditory pathway with less electrical artifact contamination. In this respect, round-window and scala tympani stimulation sites are equally efficacious.

Animals↗