Auditory function and speech discrimination abilities are impaired in progressive supranuclear palsy

Objective: To find out hearing ability and speech discrimination of progressive supranuclear palsy (PSP) patients, we performed audiological evaluation by means of Pure Tone (PTA) and Speech Audiometry (SA) of patients with PSP as compared with both normative values and sex-age matched Parkinson’s disease (PD) patients and healthy controls. Background: Hearing impairment (HI) and altered speech discrimination abilities have been previously demonstrated in patients with PD. Despite its high prevalence in elderly, HI has never been investigated in patients with PSP. Methods: We screened a series of PSP outpatients attending our movement disorders unit. Severity of motor symptoms, disease staging and ongoing therapy were recorded at baseline. Audiometric evaluation consisted of a standardized audiological examination, PTA and SA. PD patients and healthy age- and sexmatched subjects were selected as controls. Results: 15 PSP patients, 45 PD patients and 45 healthy controls were enrolled. PTA showed severe agedependent sensorineural HI in PSP patients as compared with both normative values and controls. PTA also confirmed our previous finding of high-frequency HI in PD patients. The mean values for the Speech Recognition Threshold were higher in PSP patients as compared with both PD patients and controls. Finally PSP patients showed a significant speech-tone dissociation and rollover phenomenon thus suggesting retro-cochlear pathology and pointing to a central rather than a peripheral origin of HI in PSP. Conclusions: Our results showed the presence of severe age-dependent sensorineural hearing impairment in PSP patients as compared with both normative values and controls. Moreover, SA showed impaired speech discrimination abilities in PSP patients as compared with both PD patients and healthy controls thus expanding the non-motor panel of PSP.