Objective To quantitatively assess severity of movement disability by analyzing physical activities recorded by an actigraph monitor in patients with neurology disorders.Methods Eighty-one patients with Parkinson' s disease(PD)and 61 patients with acute cerebral infarction(ACI)accompanying impaired upper limb motor function were included in the study.PD patients and ACI patients were treated using the international PD and ACI treatment guidelines,respectively.The patients were asked to wear an Actigraph monitor for 6 days before the treatment in both PD and ACI patient groups and at 24-38 days post-treatment in PD patients or at 28 days post-treatment in ACI patients.The recorded data was analyzed by power-law exponent(PLE)and detrended fluctuation analysis(DFA).Clinically,before and after the treatments,PD patients were evaluated using the conventional Unified Parkinson Disease Rating Scale (UPDRS),and ACI patients were evaluated by assessing upper limb motor function using Fugl-Meyer Assessment(FMA)and Functional Independence Measure(FIM).The correlation of the UPDRS scores with PLE was analyzed in PD patients,and the correlation of FMA or FIM with DFA in ACI patients.Results Both the UPDRS scores and the PLE values in PD patients were improved after the drug administration(UPDRS total:32.8 ± 16.2 and 28.8 ± 14.7,Z =2.080,P =0.038; UPDRS Ⅲ:18.6 ± 8.2 and 15.7±6.8,Z=2.155,P=0.031; PLE:0.98 ±0.25 and 0.82 ±0.21,Z=2.212,P=0.027,before and after the treatment,respectively).There were a linear correlation coefficient of 0.699 between the improvements of total UPDRS scores and the PLE values,and of 0.823 between the UPDRS Ⅲ and the PLE values.FMA,FIM scores and DFA were improved significantly than before treatment(FMA:12.39 ± 8.21 and 30.28 ±7.29,Z=3.016,P =0.004; FIM:8.98 ±7.29 and 13.21 ±7.6,Z =2.282,P=0.038; DFA:0.86 ±0.31 and 0.98 ±0.27,Z =2.360,P =0.036,before and after the treatment,respectively).It also showed linear correlations between the improvements of FMA scores and DFA(r =0.638),and between FIM scores and DFA(r =0.712,both P ＜0.05).There was no correlation between UPDRS scores and DFA values in PD patients,nor between FIM scores or FMA scores and PLE values in ACI patients.Conclusions Actigraph device can be used to monitor patients activity in movement disorders.Analysis of its PLE can provide a quantitative evaluation in PD while its DFA may provide useful specific assessment of impaired upper limb motor function in ACI patients.It can also be used in quantitatively assessing new drug efficacy.