Muscle Pain Intensity and Pressure Pain Threshold Changes in Different Periods of Stroke Patients

Objective This study aimed to investigate the role of muscle pain in post-stroke pain syndromes. Design This cross-sectional-designed study enrolled 145 stroke patients at three different stroke duration periods (<= 3 mos, 3 mos to 1 yr, and >1 yr) receiving inpatient or outpatient rehabilitation programs in a regional teaching hospital. Three common muscle tender points (two at the upper trapezius and one at the brachioradialis) and two relative periosteum points of the healthy and hemiparetic sides were identified for evaluation. Spontaneous pain intensity measured with the verbally reported numerical rating scale and pressure pain threshold were assessed. Associations between variables were analyzed. Results Among 145 subjects, 56 were women, and the mean +/- SD age was 62.1 +/- 13.2 yrs. The patients with stroke duration within 3 mos had the highest spontaneous muscle pain intensity and were most sensitive to pressure pain, with a prevalence of 48.3% of moderate to severe pain intensity (verbally reported numerical rating scale, 4-10) in the hemiparetic side. Spontaneous pain was more severe in the hemiparetic side than in the healthy side, but there were no obvious differences between the sides in the pressure pain threshold of the muscle or the periosteum. Conclusions In stroke patients, spontaneous muscle pain in the hemiparetic side is a common finding. Bilaterally symmetric changes of pressure pain threshold are probably caused by central sensitization mechanisms.