The effects of paired associative stimulation on motor cortex excitability and the recovery of motor function after stroke / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the effects of paired associative stimulation (PAS) on the recovery of upper limb motor function in stroke patients,and to analyze the relationship between the change of motor cortex excitability in the contralesional hemisphere and the recovery of motor function in the affected upper limb.Methods Thirty hemiplegic stroke patients were divided randomly into a treatment group and a control group.Both groups were given routine rehabilitation therapy,but the treatment group also received PAS consisting of transcranial magnetic stimulation (TMS) of the intact motor cortex and electrical stimulation (ES) of the median nerve at the wrist of the intact arm with an interval of 10 ms between the TMS and ES (PAS10).The PAS10 was delivered at a frequency of 0.05 Hz and an intensity of 120％ the resting motor threshold (RMT),once daily for 30 minutes,five times a week for 4 weeks.Corticospinal excitability was measured using motor evoked potentials (MEP) and the RMT.The FuglMeyer upper limb assessment (FMA),Brunnstrom staging and the modified Barthel index (MBI) were also applied before and at the end of the 4 weeks of treatment.Correlation was sought between any changes in MEP amplitude,the RMT of the contralesional hemisphere and changes in the FMA results.Results Before the intervention there were no significant differences between the two groups in terms of any of the assessments.After 4 weeks of treatment,all the assessments had changed significantly compared to those before the treatment,but there were still no significant differences between the two groups in terms of any the assessments.After 4 weeks of treatment,the differences in MEP amplitude from the contra-lesional hemisphere and the differences in FMA scores were positively and significantly correlated with a correlation coefficient of r =0.431.The lesioned hemisphere was also positively correlated with the differences in FMA scores with a significant correlation coefficient of r =0.608.Conclusion PAS10 can facilitate the recovery of upper limb motor function.The change in motor cortex excitability of the contra-lesional hemisphere significantly correlates with functional recovery in the upper limb.