Separately, it is known that fatiguing hand exercise reduces SICI, a measure of cortical excitability.
Findings from the present study demonstrating that fatiguing hand exercise induces changes in cortical excitability may suggest a potential pathophysiological link between ALS and fatiguing exercise.
Of further relevance, fatiguing hand exercise is associated with downregulation of inhibitory cortical processes, which appear to be important in maintaining the force output from the contralateral limb.
Given that fatiguing hand exercise affects cortical processes in healthy controls, studies in ALS patients may yet prove useful in determining the mechanisms of fatigue in ALS that in turn may have therapeutic significance.
Fatiguing hand exercise resulted in a significant reduction of SICI at ISIs of 1 and 3 ms, although the time course of SICI reduction was different for the 2 phases of SICI.
Consequently, the present study assessed effects of fatiguing hand exercise on the 2 SICI phases, using threshold tracking transcranial magnetic stimulation techniques, to yield further information on underlying mechanisms.
In conclusion, using the threshold tracking TMS technique, the present study has established that fatiguing hand exercise reduces SICI at ISI 1 and 3 ms, although the time course of reduction was different for the 2 phases of SICI.
Using novel threshold tracking TMS techniques, the present study investigated the effects of fatiguing hand exercise on different phases of cortical excitability to help clarify the mechanisms underlying the generation of SICI.
Consequently, the present study utilized the threshold tracking TMS technique to investigate the effects of fatiguing hand exercise on the different phases of SICI to provide further insights into the mechanisms underlying the generation of SICI at ISI 1 and 3 ms. Studies were undertaken on 22 right-handed healthy volunteers (12 men and 10 women, mean 46 years, age range 23 76 years).
Due to the fact that keystroke dynamics are affected by many external factors (position of hands while typing, fatigue, hand injuries, etc)., it is somehow difficult to ensure a typical pattern for a user's password every time.
Scales included the following: attention with 0 = highest level of attention, 10 = no attention; fatigue with 0 = no fatigue, 10 = highest level of fatigue and hand fatigue with 0 = no hand fatigue, 10 = highest level of hand fatigue.
