ABSTRACT
This article links two formerly separate areas of research associated with Parkinson's disease (PD): speech and memory. It is proposed that speech deficits occur in PD not merely at the level of muscular control, as is commonly termed dysarthria, but also at the level of speech planning and programming, more aptly described as a form of apraxia. It is further argued that PD patient groups exhibit small deficits in verbal span, and the link between apraxic speech and verbal span is elucidated via Baddeley's (1986) model of working memory. An experiment is described in which aspects of speech of 36 PD and 43 healthy control subjects were rated and classified, and measures of span and articulation rate for words of different syllable lengths were taken. Twenty-three PD subjects had dysarthric speech, while 14 of them had apraxic speech, which was associated with lower memory span scores for longer words. It is concluded that apraxic speech can be a source of reduced memory span in PD. In addition to implications for rehabilitation and therapeutic work with PD sufferers, these findings advance our theoretical understanding of the Parkinsonian syndrome.
Subject(s)
Apraxias/complications , Apraxias/diagnosis , Memory Disorders/complications , Parkinson Disease/complications , Adult , Aged , Aged, 80 and over , Dysarthria/complications , Dysarthria/diagnosis , Female , Humans , Male , Memory Disorders/diagnosis , Middle Aged , Severity of Illness Index , Speech Disorders/complications , Speech Disorders/diagnosis , Time FactorsABSTRACT
The issue of whether or not Parkinson's disease (PD) patients process information more slowly than normal is unresolved. Across a range of paradigms the evidence for slowing is scant, and many show no slowing. Even the results of a single experimental paradigm can be conflicting; some studies have obtained evidence for slowed memory scanning in subgroups of PD patients whereas others have not. The present study sought the cause of these discrepant results. Old-old (n = 11) and young-old (n = 7) PD subjects and controls (n = 16, n = 9) completed both fixed and varied set versions of the memory scanning task. No evidence for slowing in PD was found. These results indicated that PD did not interact with age or task version in its effects on information processing rates in the memory scanning task. It was concluded that PD patients do not have any cognitive slowing that is detectable with the memory scanning task.
