Voice quality in hereditary ataxia: pre and post-treatment comparison

Speakers with hereditary ataxias such as Friedreich's or Spino-Cerebellar Ataxia frequently experience communication problems. Whilst the level of information available on changes to articulation and prosody is increasing, less is known about vocal characteristics. In addition, most evaluations of these features are based on perceptual analyses, with little information on the acoustic properties of ataxic voice available. Finally, no reports are published to date on potential treatment benefits on the reported voice disorder, thus leaving clinicians with little guidance on how to address this problem.
19 patients with ataxia participated in Lee Silverman Voice Treatment programme. Data were collected for prolonged vowel and connected speech data, and analysed both acoustically and perceptually.
Results indicated that most participants had at least a mild level of voice impairment. This was more evident in vowel prolongation than in connected speech. Two participants presented with vocal dysfunction in addition to their ataxia, namely vocal fold palsy and laryngeal dystonia. Pre- and post-therapy comparisons indicated significant improvements in voice quality for both acoustic and perceptual dimensions, both immediately after treatment and 8 weeks later.
Our study highlights the pervasive presence of vocal problems in hereditary ataxia, and at the same time the potential to address this in therapy. Whilst none of the speakers' intelligiblity was specifically impacted by their voice problem, participants commented on a reduction of strain and effort in speaking following treatment, which in turn improved their communication participation. The study furthermore highlights the importance of a full investigation of serious vocal problems in case these need additional treatment to that provided for the ataxia.