Dissociation between source and item memory in Parkinson's disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Episodic memory includes information about item memory and source memory. Many researches support the hypothesis that these two memory systems are implemented by different brain structures. The aim of this study was to investigate the characteristics of item memory and source memory processing in patients with Parkinson's disease (PD), and to further verify the hypothesis of dual-process model of source and item memory.</p><p><b>METHODS</b>We established a neuropsychological battery to measure the performance of item memory and source memory. Totally 35 PD individuals and 35 matched healthy controls (HC) were administrated with the battery. Item memory task consists of the learning and recognition of high-frequency national Chinese characters; source memory task consists of the learning and recognition of three modes (character, picture, and image) of objects.</p><p><b>RESULTS</b>Compared with the controls, the idiopathic PD patients have been impaired source memory (PD vs. HC: 0.65 ± 0.06 vs. 0.72 ± 0.09, P = 0.001), but not impaired in item memory (PD vs. HC: 0.65 ± 0.07 vs. 0.67 ± 0.08, P = 0.240).</p><p><b>CONCLUSIONS</b>The present experiment provides evidence for dissociation between item and source memory in PD patients, thereby strengthening the claim that the item or source memory rely on different brain structures. PD patients show poor source memory, in which dopamine plays a critical role.</p>

Time perception in patients with Parkinson's disease / 中华神经科杂志

Objective To explore the impairment of time perception in patients with Parkinson's disease (PD).Method Thirty-two individuals with idiopathic PD were compared with 32 matched healthy controls using a time reproduction task.Result Compared with healthy controls for the 3-second duration reproduction task, PD patients in the setting of a delay by 1 s ( (2.78 ±0.31 ) s and (2.15 ±0.34) s,respectively) and a delay by 5 s ( (2.74 ±0.32) s and (2.08 ±0.37) s, respectively) showed impairment in time perception with a significant under-estimation of the duration ( t = - 7.459, - 7.533, both P ＜0.01 ).When compared with healthy controls for the 5-second duration reproduction task, PD patients in the setting of a delay by 1 s ( (3.99 ±0.39) s and (3.11 ±0.52) s) and 5 s ( (4.05 ±0.40) s and (2.96 ±0.54) s) also showed impairment in time perception with a significant under-estimation of the duration (t =-7.609 and - 9.120, both P ＜ 0.01 ).When compared with healthy controls for the 600-millisecond duration reproduction task, PD patients in the setting of delay by 1 s ((0.91 ±0.18) s and (0.90 ±0.18) s, respectively) and by 5 s ( (0.89 ± 0.16) s and (0.91 ± 0.17 ) s, respectively) did not have impaired time perception, and the difference was not significant ( t = 0.347, P = 0.730; t = - 0.519, P =0.606, respectively).Conclusion Our data indicates that time perception is impaired in PD patients.Impaired time perception is mainly an under-estimation of the time interval in seconds rather than milliseconds.