Brainstem auditory evoked potentials and cochlear microphonics in the HMSN family with auditory neuropathy

Abstract

The aim of this work was to assess the he ' g impairment in patients with hereditary motor and sensory neuropathy (HMSN). Elevation of pure tone thresholds in the presence of preserved inner ear function as suggested by cochlear microphonics (CM), absent or markedly abnormal brainstem auditory evoked potentials (BAEP), and elevation of speech perception out of proportion to the pure tone loss were found in the patients. From 28 members of a Gypsy family, we examined two siblings aged 3 1 and 30 years and their nephew aged 20 years, all suffering from HMSN that was associated with auditory neuropathy. All three affected members with difficulty of understanding speech had following investigations: pure tone and speech audiograms, BAEP, cochlear microphonics, and nerve conduction studies (NCV). Results: the older two siblings had a flat 80 dEi audiogram, whereas the younger one has flat 20 dB audiogram on the Lt. ear and 30 dB audiogram on the Rt. ear. All had no speech comprehension and no BAEP. Two patients had preserved cochlear microphonics on one ear. Peripheral nerves were electrically not elicitable, however, at the beginning of the disease nerve conduction was slow. Conclusion: in all three affected members with distinct clinical picture of HMSN their hearing impairment was proved to be due to severe auditory neuropathy in the presence of preserved inner ear function.

Too much of a good thing: Long-term treatment with salicylate strengthens outer hair cell function but impairs auditory neural activity

“…Third, the reductions in CAP amplitude (Figure 3) are suggestive of auditory nerve fiber or spiral ganglion dysfunction. Auditory nerve fiber dysfunctions do not have a significant effect on behavioral thresholds; the gold standard in clinical assessment (Butinar et al, 2000; Schuknecht, 1994; Schuknecht et al, 1971; Starr et al, 1996). Therefore, prolonged high-dose treatment with salicylate would likely have little effect on audiometric thresholds.…”

Cochlear Implants in Five Cases of Auditory Neuropathy: Postoperative Findings and Progress

“…Several authors 1–16 have described various aspects of auditory neuropathy (AN), including observed hearing levels, speech perception, temporal processing, and results on various objective tests, including auditory brainstem responses (ABR), transient evoked otoacoustic emissions (TOAE), distortion product otoacoustic emissions (DPOAE), electrocochleography (ECoG), and acoustic stapedius reflex thresholds (ASRT). Other authors have described possible etiologies for AN, 17–22 whereas a few authors have described single cases of cochlear implants for children with AN. 23–26 …”

Evaluation of Respiratory Muscle Strength and Pulmonary Function in Patients with Charcot-Marie-Tooth Disease Type 2

“…Sensory hearing loss can also occur [11,12] and also paresis of the vocal cords, which may be associated with a more severe variant of the disease [8]. …”