Auditory processing deficits in children with Friedreich ataxia

Abstract

Friedreich ataxia is a neurodegenerative disease with an average age of onset of 10 years. The authors sought to investigate the presence and functional consequences of auditory neuropathy in a group of affected children and to evaluate the ability of personal FM-listening systems to improve perception. Nineteen school-aged individuals with Friedreich ataxia and a cohort of matched control subjects underwent a battery of auditory function tests. Sound detection was relatively normal, but auditory temporal processing and speech understanding in noise were severely impaired, with children with Friedreich ataxia typically able to access less than 40% of the information available to controls. Use of FM-listening devices did, however, improve the speech perception performance of those with Friedreich ataxia to the level of their unaffected peers in conditions designed to replicate the listening environment of the average school classroom.

Figure 1

Mean sound detection thresholds at audiometric frequencies for Friedreich ataxia and control subjects. Error bars represent ±1 SD. The shaded area shows the normal hearing range. Abbreviations: FRDA, Friedreich ataxia; HTL, hearing threshold level; SD, standard deviation.

Figure 2

AM detection thresholds for Friedreich ataxia and control subjects (mean ±1 SD). The shaded area represents the normal range for school-aged children from Rance and colleagues. Abbreviation: FRDA, Friedreich ataxia; Mod., modulation; SD, standard deviation.

Figure 3

Consonant-nucleus-consonant phoneme scores for Friedreich ataxia and control subjects (mean ±1 SD). The shaded area represents the normal range for school-aged children from Rance and colleagues. Abbreviation: CNC, consonant-nucleus-consonant; SD, standard deviation; S/N, signal-to-noise.

Figure 4

Abbreviated Profile of Hearing Aid Benefit Hearing Disability Questionnaire findings for Friedreich ataxia and control cohorts. Values represent the percentage of everyday listening situations in which the child perceived a difficulty (Mean ±1 SD). Asterisks denote the metrics in which there was a significant difference between subject groups (P < .01). Abbreviation: FRDA, Friedreich ataxia; SD, standard deviation.

Figure 5

Unaided and FM-aided speech perception scores (CNC words at 0 dB SNR) for each of the Friedreich ataxia subjects. Also shown are the mean ±1 SD scores for the Friedreich ataxia and matched control groups. Abbreviation: CNC, consonant-nucleus-consonant; FRDA, Friedreich ataxia; SD, standard deviation; SNR, signal-to-noise ratio.