Model Simulation of the Resting Tremor Mechanism in Parkinson’s Disease / 医用生物力学

Objective To study the internal relationship between resting tremor and slow response in patients with Parkinson’s disease. Methods The movement characteristics of wrist joints in valgus direction was studied by dynamic modeling on wrist joints of the upper limbs. The system delay concept was introduced with human autonomous control and the sensory delay characteristics of Parkinson’s patients was simulated, to make stability analysis and dynamic response of the involuntary wrist movement. Results The stability analysis and numerical solution of this time-delayed control system showed that when the sensation was delayed to a certain extent, involuntary tremor of wrist joints in patients with Parkinson’s disease would happen, which conformed to resting tremor from Parkinson’s disease. Conclusions Resting tremor from Parkinson’s disease is caused by sensation and movement delay.

The characteristics of Parkinson's disease with dementia and Alzheimer's disease with impaired cognitive function / 中华内科杂志

Objective To analyze the characterization of cognitive function in Parkinson's disease with dementia and Alzheimer's disease. Methods Cognitive function was examined in Parkinson's disease with dementia (PDD) patients ( n = 30) , Alzheimer's disease (AD) patients ( n = 30) and healthy elderly control subjects ( n = 60) . Neuropsychological evaluation contained semantic fluency test, phonemic fluency test, action fluency test, objective and action naming tests. Results In PDD group , the score of semantic fluency test is 9. 33 ±2. 78, 6. 17 ± 1.67 of phonemic fluency test and 7.03 ±2. 34 of action fluency test,it is 6.90 ±2.47, 7.87±2.01,8.30±3. 17 of AD group. The score of objective and action naming tests is 36.33 ±3.39, 17.63 ±2. 17 in PDD group,while AD patients is 33.23 ±3.56 and 22.33 ±2.37. The verbal fluency tests and naming tests were impaired in PDD and AD patients compared with the healthy elderly control group (P ＜ 0. 01 ), phonemic fluency, action fluency and action naming were more impaired in PDD patients compared with the AD group , while semantic fluency and objective naming were more impaired in AD patients (P ＜ 0. 01 ). Conclusions Executive function deficit and naming impairment are found in PDD and AD patients, it shows that PDD is characterized by the addition of cortical dysfunction upon a predominant and progressive fronto-subcortical impairment. There is subcortical dysfunction in AD patients.