Deficit of short-term memory in newly diagnosed untreated parkinsonian patients: reversal after L-dopa therapy

We assessed the effect of pathology and L-dopa therapy on attention, working memory, and executive functions, in newly diagnosed Parkinson's disease patients. Twenty-one consecutive outpatients who met the criteria for de novo Parkinson's disease, and were naive for L-dopa therapy, were observed for the first time. All patients underwent clinical and neuropsychological evaluations (cognitive decline, memory, executive control). Each patient was re-evaluated on standard L-dopa therapy. Serial Position Curves showed an increased primacy effect (5.18 +/- 2.07) and a decreased recency effect (13.35 +/- 5.51). These findings normalized after L-dopa therapy (3.50 +/- 1.72 and 16.20 +/- 3.09 respectively). The effect Of L-dopa on working memory is discussed.