The differential effect of altered auditory feedback on speech in early- and late-onset of Parkinson disease.

Abstract

Advanced speech symptoms in Parkinson disease (PD), such as “festinating speech” or palilalia and frequent hesitations, are a clinical challenge. This report is a part of a larger study testing the hypothesis that the use of altered auditory feedback (AAF) would improve speech intelligibility in patients with PD and more advanced speech impairment. Our initial report showed that the use of AAF indeed improved speech intelligibility in these patient’s spontaneous speech [Wang et al. (2008)]. In this report, the spontaneous speech samples produced by four older-onset (aged 72.4 SD 6.02 years) vs four young-onset PD patients (aged 54.2 SD 4.44 years), with and without the use of AAF, were analyzed. The results indicated that, regardless of the use of AAF, the older-onset patients performed poorer than the young-onset patients in many areas including the mean length of utterance in words, number of different word roots, within utterance pause time, and words per minute. These findings are consistent with the report that patients with an older age at onset had more rapid progression of PD than those with a younger age at onset in mentation, freezing, and activities of daily living. Possible underlying mechanism for the findings will be discussed.