Biomedical subjects

A Boerst

Publications and source records attributed to A Boerst.

5 recordsLinked to original sources

PubMed2001

Multichannel cochlear implantation in visually impaired patients.

OBJECTIVE: To evaluate the outcome of cochlear implantation in patients with severe to profound hearing loss and visual impairment. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center with a large cochlear implant program. PATIENTS: Six adults and two children with severe or profound hearing loss and significant visual impairment underwent multichannel cochlear implantation. Follow-up period ranged from 6 months to 9 years. Case history, etiology of visual and hearing loss, and benefit from cochlear implant were evaluated. INTERVENTIONS: Cochlear implantation and subsequent rehabilitation. MAIN OUTCOME MEASURES: Speech perception measures were selected based on the patient age and cognitive abilities. Identical measures were used in each patient before and after implantation. RESULTS: As a group, patients did well after cochlear implantation. There was significant improvement in speech perception when compared with the score before implantation. CONCLUSIONS: Cochlear implants can play a significant rehabilitative role in patients with severe visual and auditory impairment. Additional skills are required by the implant team for rehabilitation of patients with multiple sensory deficits.

Adult↗

PubMed1999

Successful cochlear implantation in a patient with MELAS syndrome.

OBJECTIVE: To describe methods of assessing cochlear implant candidacy in patients with potentially significant peripheral and central nervous system (CNS) degeneration. STUDY DESIGN: A patient with a degenerative CNS disease (MELAS syndrome) undergoing evaluation for cochlear implantation is described. SETTING: This study took place at a tertiary care center. PATIENT: A patient with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) who had cortical blindness and profound sensorineural hearing loss was evaluated and rehabilitated with cochlear implantation. INTERVENTIONS: Pure-tone audiogram, behavioral responses to promontory stimulation electrical auditory brainstem response, and electrically evoked middle-latency responses (MLRs) were used to assess eighth nerve, auditory brainstem, and cortical auditory pathways. Cochlear implantation with Cochlear Corporation mini 22 implant was performed. RESULTS: Repeatable electrically evoked MLRs and behavioral responses to promontory stimulation documented the presence of auditory cortical responses. Successful implantation resulted in open set speech recognition and communication using the auditory/oral mode. CONCLUSION: This report describes successful implantation in a patient with MELAS syndrome and demonstrates the ability to preoperatively confirm the integrity of brainstem and cortical auditory pathways despite significant CNS degeneration.

Adult↗

PubMed1998

Performance with the 20 + 2L lateral wall cochlear implant.

OBJECTIVE: The purpose of this study was to investigate the operating characteristics of the Nucleus 20 + 2L lateral wall cochlear implant including speech recognition results. STUDY DESIGN: This was a prospective randomized study involving five different modes of stimulation. SETTING: This study was carried out in an academic, tertiary referral center. PATIENTS: The patients included in this study were adult cochlear implant candidates ages 44-74 years. Length of deafness ranged from 1 to 58 years with a variety of etiologies. INTERVENTIONS: All patients were implanted with a 20 + 2L implant, which includes an intrascalar electrode array and an apically placed extracochlear, titanium encased ball electrode in contact with the endosteum of the apical turn. All patients underwent psychophysical and speech recognition testing in five different modes of electrode configuration. MAIN OUTCOME MEASURE(S): The main outcome measures included thresholds, comfort levels, dynamic ranges, and speech recognition results obtained in five electrode configuration modes. RESULTS: Thresholds were significantly lower (repeated measures ANOVA) in both monopolar conditions when compared to bipolar mode of stimulation. A binomial statistical analysis indicated that in five of nine patients activated in all five modes of stimulation, the monopolar modes of stimulation resulted in improved speech recognition scores. CONCLUSIONS: The results of the study demonstrate the feasibility of the use of an apical lateral cochlear wall electrode in conjunction with an intrascalar electrode array. It further demonstrated the superiority of monopolar stimulation in selected patients.

Adult↗

PubMed1997

Cognitive evoked potentials to speech and tonal stimuli in children with implants.

We investigated late and cognitive (mismatch negativity, P300) auditory potentials in 14 children with cochlear implants between the ages of 4 and 12 years. Length of cochlear implant use ranged from 7 to 84 months. Three types of stimulus contrasts were used: (1) a loudness contrast consisting of a 1500 Hz tone burst presented at 75 (standard) and 90 dB sound pressure level (deviant); (2) a frequency contrast consisting of a 1500 Hz tone burst (standard) and a 3000 Hz tone burst (deviant) presented at 80 dB sound pressure level; and (3) a speech contrast consisting of "heed" (standard) and "who'd" (deviant) delivered with a roving loudness paradigm involving a randomized variation of the levels of the standard and deviant stimuli. Latencies and amplitudes of components N1, P2, N2, and P3 and a mismatch negativity were measured. Overall, there were very few missing or unidentifiable components. P3 and mismatch negativity components were identified for all subjects and all stimuli. The latencies of most components were affected by stimulus type. There was a trend for longer latencies for the speech contrast compared with the loudness or frequency contrasts. This may be a reflection of the increased processing time required for the speech stimuli because of its higher complexity. There were several significant correlations between speech recognition and cognitive evoked potential latencies. These results indicate that the clinical use of cognitive evoked potentials in children with cochlear implants is feasible and informative.

Acoustic Stimulation↗

PubMed1997

Electrically evoked auditory potentials: current clinical applications in children with cochlear implants.

OBJECTIVE: To summarize the current applications of auditory evoked potential in children with cochlear implants and candidates for implantation. PATIENTS AND METHODS: Perioperative transtympanic EABR is used routinely for ear selection and to establish the electrical stimulability of the ear intended to be implanted. The perioperative transtympanic EABR is supplemented with EABR obtained immediately following the insertion of the electrode array and the seating of the implant's receiver. Postoperatively, EABR and averaged electrode voltages are used effectively to properly adjust the implant stimulus parameters and to determine whether the implant is functioning adequately. Postoperatively, cognitive evoked potentials to speech and tonal stimuli may also be obtained. RESULTS: EABR results have contributed to effective implant placement and function. There were several significant correlations between speech recognition and cognitive evoked potential. CONCLUSION: These measures help assure proper implant function and effective stimulus delivery.

Adolescent↗