Patients with multiple sclerosis experience hearing loss specifically for shifts of tone frequency
D. B. Quine, D. Regan, K. I. Beverley and T. J. Murray
After exposure to a prolonged tone of changing intensity but constant
frequency, controls, patients with peripheral hearing loss, and patients
with multiple sclerosis (MS) demonstrated a reduced sensitivity to shifts
in intensity; sensitivity to frequency shifts was unaffected. After
exposure to a prolonged tone of changing frequency but constant intensity,
control and patients with peripheral hearing loss demonstrated reduced
sensitivity to shifts in frequency; sensitivity to intensity shifts was
unaffected. Some patients with MS showed no loss of sensitivity to shifts
in frequency. Our findings suggest that some patients with MS have abnormal
mechanisms for processing changes of frequency. If such processing of
frequency change is important for understanding speech, then this
observation of a specific central hearing defect may help to explain poor
speech discrimination in some patients with MS who have normal audiograms.
