Twenty Seconds of Finger Tapping: A Borderland for Contralateral Transfer of Repeated Bout Rate Enhancement

Background: To test the hypothesis that a 20-s bout of unilateral index finger tapping, followed by 10 min rest, increases the freely chosen tapping rate performed by the contralateral index finger, in a second 20-s bout. Methods: Twenty healthy adults performed tapping with the index finger on one hand followed by a 10 min rest period and tapping with the other index finger. Tapping was performed at freely chosen rate. Testing was performed with dominant hand first as well as in the opposite order. Results: Freely chosen tapping rates from the first bouts were 161.6 ±94.2 and 162.8 ±80.3 taps per min for the dominant and non-dominant hand, respectively (p=0.903; R=0.89, p 0.001). When bout one was performed with the non-dominant hand, the rate increased by 15.0% ±22.3% in about two (p=0.008). In the opposite order, the rate remained similar (+4.8% ±17.9%, but p=0.655). Conclusion: Based on the present, as well as previously published results, the interpretation is that 20 s of initial index finger tapping appears to constitute a borderland for elicitation of subsequent contralateral excitation of freely chosen tapping rate.