Deficit of verb generation in nondemented patients with Parkinson's disease

Abstract

Clinical and neuroimaging studies have shown that verb processing suggests a preferential participation of a prefrontal network, which is dysfunctional in Parkinson's disease (PD). To assess a verb processing deficit in PD, we compared noun- and verb-generation tasks for 34 nondemented PD patients (according to the Dementia Rating Scale) with 34 matched normal subjects, using two intracategory tasks (noun/noun and verb/verb generation) and two intercategory tasks (noun/verb and verb/noun generation). PD patients were significantly impaired in the two tasks involving verb production, i.e., verb/verb and noun/verb generation, whereas their performance was similar to those of controls in the two tasks requiring noun production. For the two impaired tasks, we assessed 1) the influence of lexical competition that corresponds to the presence of several candidate words for a given stimulus; 2) the influence of slight cognitive dysfunction; and 3) the influence of motor deficit. Significant correlations were found between DRS scores and performance on the noun/verb task, and no significant correlations were found between lexical competition or motor deficit and performance. The specific deficit for verb production in PD patients is discussed in relation to deficits affecting either action or grammatical representations.

Patterns of neuropsychological impairment in MCI patients with small subcortical infarcts or hippocampal atrophy

“…This neuropsychological marker seen in our vascular MCI patients, suggesting a likely frontal lobe involvement, is consistent with the hypothesis assuming that small vessel subcortical dementia may be due to the disruption of corticostriatal loops that subserve the functions of the frontal lobes, coursing through the frontal white matter (Alexander & Crutcher, 1990;Cummings, 1993). The fact that a greater impairment in the generation of verbs than in the generation of nouns has been reported by Peran et al (2003Peran et al ( , 2004 in patients with other "subcortical" forms of dementia (Huntington's Disease and Parkinson's Disease) also supports this interpretation.…”

Quantitative analysis of language production in Parkinson's disease using a cued sentence generation task

“…Beilen, Leender, Post, & Bastiaanse, 2009) or a combination of both (Péran et al, 2003) is a matter of 1 debate. Decreased activation of the frontal cortex, due to reduced stimulation from the basal ganglia, is 2 considered to be the common underlying mechanism (Cotelli et al, 2007).…”

Language Processing in Parkinson's Disease Patients Without Dementia

“…According to these authors, verb fluency reflects the underlying integrity of frontal lobe circuitry, and problems on verbal fluency tasks could therefore indicate deficits in executive functioning. Péran et al (2003) developed a French word generation task that requires a semantic and grammar driven selection of single words over a limited time period. Compared to healthy control participants, non-demented PD patients made more grammatical errors in the noun-verb-generation task than in the verb-noun-generation task.…”

“…Compared to healthy control participants, non-demented PD patients made more grammatical errors in the noun-verb-generation task than in the verb-noun-generation task. Péran et al (2003) suggested that this discrepancy was due to the combined effect of impaired set switching and a specific grammatical impairment in verb production. The authors assume that in the verb-noun task, the impact of impaired switching is compensated by the easier noun production, whereas in the noun-verb task both the switching and production of the verb were dysfunctional.…”

“…One explanation for the discrepancy between verb and noun retrieval is that verb retrieval is more demanding than noun retrieval in terms of executive functioning (e.g., Péran et al, 2003;Piatt et al, 1999a and1999b). The idea is that retrieving the name of an object elicits a more automatic lexical retrieval response than retrieval of the action name, which demands a more controlled retrieval.…”