In single sided deafness, treatment with transcranial CROS makes pseudo stereophonic listening possible. This leads to improved speech understanding in noise. However, several reports show large variations between the individual results of the benefit by speech audiometry in noise. One possible factor is the duration and changes in the auditory pathway between the onset of deafness to CROS supply. 18 patients with single sided deafness have tested a transcranial CROS supply. The speech intelligibility thresholds were evaluated in 2 spatial hearing situations each with CROS and unaided. When speech was arriving at 45° from the deaf ear and noise at 45° from the hearing ear, a significant improvement of speech reception threshold for 50% intelligibility was detected by CROS supply compared the medians. Patients with longer duration of deafness showed higher benefit by an average of -4.0 dB, in contrast to patients with short duration of deafness. In the reversed situation, that speech on the hearing ear and noise on the deaf ear was a significant deterioration observed, an average of 3.1 dB at longer deafened patients. In addition, a highly significant correlation was found with the individual changes in the speech recognition threshold between the two situations. The duration of deafness is an essential factor in the individual benefit estimate for treatment with transcranial CROS supply. The time frame for audimetrically proven changes in the auditory pathway as a result of unilateral auditory deprivation can be estimated to about 1-3 years. Patients with short duration of deafness have low or no benefit from transcranial CROS supply.

Electrical stimulation by cochlear implant (CI) has been proven to be a viable treatment option for tinnitus in many recent studies. In addition, intracochlear electrical stimulation independent of an acoustic input appears to suppress tinnitus, at least in the short term. We conducted a case study to investigate the long-term effects of both standard CI and intracochlear electrical stimulation independent of an acoustic input on tinnitus in a patient with single-sided deafness and tinnitus. We found no negative effects of intracochlear electrical stimulation independent of an acoustic input on speech perception in noise. Furthermore, the additional use of a standard CI was advantageous for speech discrimination in our patient. We conclude that long-term tinnitus suppression can be achieved via intracochlear electrical stimulation with looped patterns. Our findings in terms of speech discrimination in our patient were consistent with those reported in previous studies.

OBJECTIVE: This manuscript describes a case in which, based on clinical observations, we hypothesize that a change in a cochlear implant recipient\'s electrode impedance and performance was attributed to a change in the recipient\'s physiology rather than a device failure. Of particular note was the finding that electrode impedances decreased after a period of nonuse of the implant as well as after steroid treatment.
METHODS: Retrospective single-subject case study review.
METHODS: Outpatient clinic.
METHODS: This paper describes outcomes for a 75-year-old male cochlear implant user.
METHODS: A change in electrode impedance and a decrease in speech recognition were addressed through cochlear implant programming, periods of nonuse of the implant, provision of steroids, and bilateral cochlear implantation.
METHODS: The primary measures of interest were serial assessment of electrode impedance and speech recognition. Secondary measures included assessment of implant stimulation levels and electrophysiologic responses.
RESULTS: Electrode impedances decreased (improved) after a period of nonuse of the implant as well as after provision of steroid treatment. Recipient performance also improved but did not return to baseline levels.
CONCLUSIONS: Atypical fluctuations in electrode impedance were observed with periods of CI use and nonuse. Additionally, after a 10-month period of constant fluctuation of electrode impedances with atypical morphology, electrode impedances stabilized to normal levels with a typical morphology within 3 days of steroid treatment. Given these observations, we hypothesized that the change in this recipient\'s electrode impedance as well as the decrease in this implant recipient\'s performance may be attributed to his physiology rather than to the device failure. Changes in electrode impedance accompanied by a decrease in this patient\'s performance were successfully addressed by a period of nonuse of the implant, provision of steroids, and an increase in the pulse width of the biphasic pulsatile signal used for stimulation. It should be noted that the results of this case are anecdotal in nature and may not apply to all cochlear implant recipients experiencing electrode impedance changes and/or deterioration in performance.

An 81-year-old female was referred for cochlear implantation due to difficulty communicating in her daily activities despite the use of appropriate amplification. The poorer ear was unable to tolerate amplification for the past 15 years. The open-set sentence-recognition test score in quiet in her \"good\" ear was 85 percent correct, indicating that the patient was not a traditional cochlear implant candidate. However, the sentence-recognition score in noise at +10 dB signal-to-noise ratio was 0 percent, demonstrating a significant breakdown in the patient\'s speech understanding in more difficult listening situations. This speech-in-noise score appeared to correlate with the patient\'s reported communication difficulties as well as with the communicative breakdowns that were observed clinically. The patient underwent cochlear implantation in the better ear. Cochlear implantation in this nontraditional patient provided objective and subjective benefit over hearing aid use.

OBJECTIVE: Since 1991, three separate reports have shown how hearing may be salvaged after translabyrinthine excision of small acoustic tumors. The authors submit yet another report of a complete translabyrinthine excision of a 1.4-cm intracanalicular acoustic tumor with modest hearing preservation. An attempt is made to retrace the steps of the operation and recognize and discuss what particular events may have safeguarded the viability of the cochlea. With the availability of cochlear implantation, there should be added incentive to preserve the cochlear neurones if hair cells cannot be saved.
METHODS: The study design was a retrospective case review.
METHODS: The study was conducted at a primary care hospital.
METHODS: Therapeutic and rehabilitative measures were performed.
METHODS: Hearing preservation was measured.
METHODS: A 55-year-old woman presented with a left-sided hearing loss and a 1.4-cm left acoustic tumor completely filling the internal auditory canal (speech reception threshold [SRT] 30 dB, discrimination [Pb] 28%). A successful translabyrinthine excision of the tumor was performed in November 1995. A 1-year postoperative audiogram showed a mixed hearing loss in the left ear with SRT 85 dB and Pb 0%. Average pure-tone threshold for 500 Hz, 1 kHz, and 3 kHz was 50 dB and aided SRT 40 dB with Pb 64%. Postoperative magnetic resonance imaging confirmed complete excision of the tumor.
CONCLUSIONS: An exceptional case of hearing preservation after translabyrinthine excision of a small acoustic tumor illustrates how it may be possible to preserve cochlear hair cells and neurones simultaneously in certain selected cases. A review of the surgical events shows the value of sealing the cochlear duct with bone wax, selectively removing the vestibular nerves with the tumor by sharp dissection, and safeguarding the meatal segment of the anterior inferior cerebellar artery by a limited dural incision.

We evaluated a 28-year-old female with a unilateral hearing loss of unusual pathogenesis, that of central nervous system miliary tuberculosis. Audiologic and otologic findings were consistent with left retrocochlear disorder, characterized by a profound hearing sensitivity loss, absent acoustic reflexes, normal otoacoustic emissions, and the presence of only wave I of the auditory brainstem response. Imaging studies revealed the presence of multiple punctate lesions, one of which was extra-axial and located at the left cerebellopontine angle. The pattern of audiometric test results, particularly the combination of normal otoacoustic emissions and profound hearing sensitivity loss, contributed importantly to the investigative sequence leading to the final diagnosis.

The large vestibular aqueduct (LVA) syndrome is a congenital malformation that predisposes the patient ultimately to a loss of hearing and possible continuing vestibular disorder. If the LVA patient is diagnosed, it typically is not until later life, when he/she exhibits profound sensorineural hearing loss. To better understand this disorder and to bring it to the attention of audiologists, we provide a brief tutorial of LVA and present three case studies that illustrate the syndrome.

This paper describes audiologic, electrophysiologic, and medical test results for a now 10-year-old girl who has had 45 episodes of reversible, sudden sensorineural hearing loss over the last 8 years. Episodes have lasted from 6 to 72 hours and often have been accompanied by a mild illness. Acoustic immittance measures have been consistent with normal middle-ear function with the exception of absent ipsilateral and contralateral acoustic reflexes. Mechanically evoked perioral reflex activity was markedly asymmetric following lower lip stimulation. The asymmetry of R1 activation between right and left side lower lip inputs raises questions about the integrity of central connections within the brain stem, including internuncial pathways coursing between trigeminal sensory relay nuclei and the facial motor nucleus. An electrocochleographic evaluation revealed cochlear microphonic but absent or markedly abnormal whole nerve action potentials. Auditory brainstem responses (ABR) have been either absent or poorly formed and significantly delayed, regardless of hearing sensitivity. Middle and late auditory evoked potentials were essentially normal. Both transient-evoked and distortion-product otoacoustic emissions were present regardless of peripheral auditory sensitivity. All medical tests have been essentially normal. Although no definitive diagnosis has been reached, beta blockers have been used with some success. Taken together, these data document a very unusual case of fluctuating hearing loss. The electrocochleographic and otoacoustic emission data suggest that the outer hair cells are functioning normally and that the loss is not cochlear in origin.(ABSTRACT TRUNCATED AT 250 WORDS)

We present the case of an adult male whose internal cochlear implant unit failed. Several months elapsed following initial stimulation with the implant before the problem was identified and corrected. The sequence of the failure and its detection are detailed. Following reimplantation, the patient did not initially report improved sound quality. However, within a week of the initial stimulation of the second device, he reported being able to identify environmental sounds, and speech began to sound the way he remembered it before he lost his hearing. We suggest a method of detection that might improve the early identification of a nonfunctioning device or of nonfunctioning individual electrodes. Knowledge of specific nonfunctioning electrodes is important in device adjustment, especially for young children.

This report describes a patient whose ability to understand speech had so deteriorated over 20 years time that she was being considered for a cochlear implant, despite the fact that pure-tone sensitivity loss had not deteriorated proportionately. An unusual combination of otoacoustic emissions (OAEs) and auditory evoked potential (AEP) results are described. Click-evoked and distortion product emissions were present and normal-appearing. Auditory brainstem and middle latency responses were totally absent but the N1-P2 complex of the long-latency response was present. The case illustrates the contribution of otoacoustic emissions to site of lesion testing. It also illustrates that the manifestations of pathology can appear in certain epochs of the family of AEPs without affecting the others.