Juha-Pekka Vasama

Idiopathic sudden sensorineural hearing loss: temporal bone histopathologic study.

We microscopically examined the temporal bones of 12 ears with idiopathic sudden sensorineural hearing loss (iSSNHL), 10 ears with presbycusis, 11 ears with normal hearing, and 8 unaffected contralateral ears of patients with iSSNHL. The degeneration of the spiral ligament, vascular stria, hair cells, dendrites, and apical spiral ganglion cells was greater in ears with iSSNHL than in the other groups. The apical ganglion cells were significantly more affected than the basal ganglion cells, and the spiral ganglion cell loss increased as a function of duration of iSSNHL. Cochlear ossification was found in 1 ear with iSSNHL, and hydrops in 2. These findings suggest a viral rather than a vascular or ruptured inner ear membrane origin for iSSNHL.

Auditory pathway plasticity in adult humans after unilateral idiopathic sudden sensorineural hearing loss

We recorded auditory evoked magnetic fields from 8 patients with unilateral, idiopathic, sudden, sensorineural hearing loss and from 8 healthy controls, using a 122-channel whole-scalp neuromagnetometer. The stimuli were 50-ms l-kHz tone bursts, delivered to the healthy ear at interstimulus intervals (ISIs) of 1, 2, 4, 8, and 16 s. On average, as in normal-hearing controls, the dipole moments and the latencies of N100m, the 100-ms response, increased as a function of ISI over both hemispheres to left- and right-ear stimulation. Four patients had shorter response latencies and 4 had stronger dipole moments over the hemisphere ipsilateral to the stimulation. In 3 patients, one additional source was observed over the anterolateral right hemisphere and another near head midline. These findings suggest that unilateral sensorineural hearing loss may modify information processing in the central auditory pathways.

Long-term hearing results after stapes surgery: a 20-year follow-up.

Objective The aim of this study was to evaluate the results of stapes surgery after 20 years of follow-up and to compare the results between large fenestra versus small fenestra stapedotomy. Study Design Retrospective clinical study. Setting Tertiary referral center (university hospital). Patients One hundred forty-two patients with otosclerosis treated by surgery. Intervention Eighty patients had a total stapedectomy with House-wire prosthesis and 62 patients a stapedotomy with Teflon-piston prosthesis. Main Outcome Measures Preoperative, postoperative, and long-term hearing thresholds were compared. Patients filled in a questionnaire about the impact of surgery on the quality of life and postoperative symptoms. Results The long-term pure tone average improvement did not differ significantly between the techniques compared with the preoperative values. The air-bone gap tended to enlarge as a function of time. The change in the pure tone average was 0.9 dB per year for both techniques. In the questionnaire, some patients reported vertigo, tinnitus, loud noise intolerance, and taste disturbances. Loud noise intolerance seemed to persist in the long term. Surgery had no effect on preoperative tinnitus. Conclusions There were no statistically significant differences between the techniques regarding hearing results. Over the long term, both techniques are safe and effective in restoring hearing and improving quality of life.

Abrupt unilateral deafness modifies function of human auditory pathways

&NA; We studied nine patients with unilateral abrupt deafness caused by acoustic neuroma surgery. Cortical responses to tones delivered to the intact ear were recorded postoperatively with a 122‐channel whole‐scalp neuromagnetometer. In three patients, followed for 12 months with 2‐4 measurements, evoked responses originating in the auditory cortices were weak and delayed one month after the operation in both hemispheres. During the follow‐up, the amplitudes reached the control level. No response abnormalities were found in patients who were studied 1.5‐4.5 years after the operation. Our findings suggest that abrupt unilateral deafness causes immediate changes in the function of auditory pathways of adult humans and that reorganization takes place within 1 year.

Meniere's Disease and Endolymphatic Hydrops Without Meniere's Symptoms: Temporal Bone Histopathology

We studied temporal bone histopathology in 21 ears with Menieres disease and 24 ears with endolymphatic hydrops without Menieres symptoms and compared the findings to those in 10 ears with presbycusis and 11 ears with normal hearing. Normal hearing ears showed less degeneration of cochlear structures than the other ears. In ears with endolymphatic hydrops without Menieres symptoms, the degeneration of spiral ligament, hair cells, dendrites (peripheral processes) and apical spiral ganglion cells was more severe than in the other three groups. In ears with Menieres disease and endolymphatic hydrops without Menieres symptoms, the hair cells and dendrites were more affected than ganglion cells and there was no correlation between hair cell and ganglion cell degeneration. These findings suggest that a permanent threshold shift in late stage endolymphatic hydrops is not related to ganglion cell loss but rather to degeneration of sensory elements.

Auditory cortical responses in humans with congenital unilateral conductive hearing loss.

We recorded auditory evoked magnetic fields from 6 patients with congenital unilateral conductive hearing disorder with a 122-channel whole-head neuromagnetometer. The stimuli were 50-ms 1-kHz tones delivered to the better ear at interstimulus intervals (ISIs) of 2 and 8 s at two different intensities (50 and 70 dB HL). As in normal-hearing subjects, the amplitudes of N100m, the 100-ms response, were larger in 5 patients and the latencies were shorter in 3 patients over the hemisphere contralateral to stimulation. However, in one patient N100m peaked already at 61 ms over the contralateral hemisphere and amplitudes were larger over the ipsilateral hemisphere, possibly reflecting reorganization of the auditory pathways. In 3 patients the latencies were shorter over the ipsilateral hemisphere. The effects of ISI and intensity were similar over both hemispheres and did not differ from those in controls. It seems that congenital unilateral conductive hearing loss does not necessarily lead to any gross disturbances in the human auditory cortex.

Effects of intensity variation on human auditory evoked magnetic fields

We recorded auditory evoked magnetic fields from 6 healthy subjects with a 122-channel whole-head neuromagnetometer. The stimuli were 200-ms 1-kHz tones delivered at 4 different intensities (40, 50, 60, and 65 dB HL). The tones were given once every second, binaurally in the first session, and monaurally to each ear in the second one. The four intensities were presented randomly and equiprobably within a single sequence. In both stimulus conditions, the 100-ms response (N100m) decreased in latency and increased in amplitude as a function of intensity in both hemispheres. No systematic dependence was found between stimulus intensity and the N100m source location in the auditory cortex. Our study illustrates a noninvasive method to examine the functional properties of human auditory cortex, allowing simultaneous comparison between signals arising from both hemispheres.

Surgery for External Auditory Canal Exostoses: A Report of 182 Operations

The pre-operative findings and operative outcome were evaluated from patient records in 136 patients (182 ears) who had surgery for external auditory canal (EAC) exostoses. Furthermore, 114 patients (84%) replied to a questionnaire inquiring about the symptoms and the operation’s impact on their quality of life. The main symptoms prior to the surgery were recurrent external otitis, hearing loss and wax retention. Interestingly, 23 patients (21%) were operated without any symptoms. After the operation, 75 patients (66%) had relief of their symptoms. In 33 patients (29%) the symptoms remained the same, and in 5 patients (4%) they became worse. The quality of life improved in 77 patients (68%); 19 patients (14%) had a complication due to the surgery, and 8 patients (6%) needed a re-operation. The surgery for EAC exostoses should be reserved only for symptomatic cases and only for experienced specialists in order to minimize complications and unnecessary operations.

MODIFICATION OF AUDITORY PATHWAY FUNCTIONS IN PATIENTS WITH HEARING IMPROVEMENT AFTER MIDDLE EAR SURGERY

We recorded auditory-evoked magnetic responses with a whole-scalp 122-channel neuromagnetometer from seven adult patients with unilateral conductive hearing loss before and after middle ear surgery. The stimuli were 50-msec 1-kHz tone bursts, delivered to the healthy, nonoperated ear at interstimulus intervals of 1, 2, and 4 seconds. The mean preoperative pure-tone average in the affected ear was 57 dB hearing level; the mean postoperative pure-tone average was 17 dB. The 100-msec auditory-evoked response originating in the auditory cortex peaked, on average, 7 msecs earlier after than before surgery over the hemisphere contralateral to the stimulated ear and 2 msecs earlier over the ipsilateral hemisphere. The contralateral response strengths increased by 5% after surgery; ipsilateral strengths increased by 11%. The variation of the response latency and amplitude in the patients who underwent surgery was similar to that of seven control subjects. The postoperative source locations did not differ noticeably from preoperative ones. These findings suggest that temporary unilateral conductive hearing loss in adult patients modifies the function of the auditory neural pathway. (Otolaryngol Head Neck Surg 1998;119:125-30.)

Single-Sided Deafness: The Effect of Cochlear Implantation on Quality of Life, Quality of Hearing, and Working Performance

Aims: To evaluate the effect of a cochlear implant (CI) on quality of life (QoL), quality of hearing (QoH), and working performance in patients with single-sided deafness (SSD). Methods: Using specific questionnaires, we measured QoL, QoH, and working performance in 7 SSD patients scheduled for CI surgery of the affected ear. Sound localization and speech perception in noise were also assessed. All questionnaires and tests were performed before the CI surgery and at 6 and 12 months after CI activation. Results: The QoL, QoH, sound localization, and speech perception in noise had improved statistically significantly after CI surgery. Communication with co-workers became easier, and the patients were less fatigued after the working day. Conclusions: CI clearly improves QoL, QoH, and working performance in patients with SSD.