Systematic analysis of language deficits related to cognitive functioning in Parkinsonian patients
Resumen
The present study investigated the relationship between executive function, short-term memory and language usage in Parkinsonian patients. Performance on the Executive Interview (EXIT) and the Logical Memory subtests of the Wechsler Memory Scale - Revised (WMS-R) was compared between PD stages 2, 3, and 4 and age-similar controls (N = 39). Language fluency and error patterns, as well as sequencing, were assessed by analyzing transcripts of audiotaped responses to the Logical Memory measures and the Spontaneous Speech subtest of the Western Aphasia Battery (WAB).
Results showed a gradual trend of impairment on the EXIT with increasing severity'of PD. Across all stages, Parkinsonians showed difficulties in immediate and delayed recall.
Parkinsonians had more difficulty with sequencing and reduced memory for key words and details. Story complexity on LMI and LMII adversely affected PD performance. When grouped by EXIT scores rather than PD stage, memory differences were less distinct, suggesting these differences were related to PD and not executive function alone.
On language measures, Parkinsonians performed as well as controls overall. PD patients had more tangential speech and overall speech errors than controls. Parkinsonians made more concept substitutions or confabulation errors than controls. This pattern of embellishing stories with additional information or replacing correct information with similar plausible material often occurs with frontal system involvement (Fischer, et. al, 1995; Papagno & Baddeley, 1997; Cunningham, et. al, 1997).
These findings suggest a relationship between cognitive deficits, PD stage and language functioning. PD patients' overall language skills were adequate for this type of task, but subtle cognitive changes could be detected through language assessments.