Working memory in Parkinson's disease patients: clinical features and response to levodopa.

Objective: To evaluate the clinical features of the working memory (WM) in Parkinson's disease (PD) patients and to test the effect of levodopa on WM.

Method: The paradigm was based on the 'n-back' tasks, which enables to study the level of executive demand (three levels of difficulty) and the domain of the information being processed (spatial items, faces and letters). The effect of levodopa was studied by testing PD patients in "on" and "off" states.

Effects of internal clock and memory disorders on duration reproductions and duration productions in patients with Parkinson's disease.

Patients with Parkinson's disease (PD) exhibit deficits in perceptual and motor timing as well as impairments in memory and attentional processes that are related to dysfunction of dopaminergic systems in the basal ganglia. The aim of the present study was to assess the relationships existing between impaired duration judgments and defective memory and attention in PD patients. We compared time performance of medicated PD patients and control subjects on a duration reproduction task that is highly memory-dependent, and on a duration production task that could reveal effects of changes in the speed of internal time-keeping mechanisms.

Separating storage from retrieval dysfunction of temporal memory in Parkinson's disease.

Dysfunction of the basal ganglia and the brain nuclei interconnected with them leads to disturbances of movement and cognition exemplified in Parkinson's disease (PD) and Huntington's disease, including disordered timing of movements and impaired time estimation. Previous research has shown that whereas striatal damage in animals can result in the loss of temporal control over behavior, dopaminergic deregulation in the human striatum associated with PD distorts the memory for time. Here we show a dissociation between deficits in storage (writing to) and retrieval (reading from) temporal memory processes.

[Procedural learning and Parkinson disease: implication of striato-frontal loops].

Objective: To investigate procedural learning in non demented patients with idiopathic Parkinson's disease (PD).

Background: Experimental evidence implicate the basal ganglia in procedural learning. Selective impairment has more recently been described in patients with frontal lesions.

Procedural learning and striatofrontal dysfunction in Parkinson's disease.

The neural basis of procedural learning remains controversial. We further analyzed procedural learning in nondemented patients with Parkinson's disease (PD) according to the specific demands of the tasks and the severity of striatal and frontal lobe dysfunction. In the first experiment, the performance of 20 nondemented PD patients and matched normal control subjects was studied in two procedural learning tasks, rotor pursuit and mirror reading, that differ in terms of motor and cognitive involvement.