Effects of Stroke on Finger Tapping
Introduction: Stroke is the number one cause of disability in the United States of America. The mechanism underlying cortical plasticity needs to be more thoroughly understood in order to discover better treatments. Careful studies of motor behavior may be useful in this regard.
Method: In this study, 32 subjects were recruited, and 45 trials were conducted. All subjects were given thorough neurological exams, including valid and reliable scales. Subjects were also asked to perform index-finger-tapping repeatedly over a 3 minute 20 second time interval, driven by a metronome. The taps were translated from analog into digital signals, then analyzed using a statistical analysis software.
Result: Coefficient of variation (CV) of force was greater than that of frequency for both controls and patients. CV of frequency in patients was greater than controls. CV of frequency was 15.69 ± 7.93 for patients, and 8.93 ± 2.68 for controls (p<0.0005); CV of force was 38.07 ± 13.78 for patients and 31.22 ± 13.23 for controls. For patients with paretic right hands, the mean Purdue score for unaffected left hands was 9.93 ± 2.30; for patients with paretic left hands, the mean Purdue score for the unaffected right hands was 10.56 ± 2.60 (controls: 13.72 ± 2.11).
Discussion: Patients showed a wider range of variability in tapping frequency than controls. However, there was not a significant difference in tapping force between the two groups. The majority of controls and patients showed significant change in frequency and/or in force over time of motor evaluation. For stroke patients, their performances on the unaffected hands were slightly impaired by stroke deficits.
