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The analysis of auditory evoked brain potentials in recurve archery

Ertan, Hayri
Archery can be described as a static sport requiring strength and endurance of the upper body, in particular the shoulder girdle (Mann, 1984; Mann & Littke, 1989). To get a good record in an archery competition, one requires well-balanced and highly reproducible movements during the shooting (Nishizono, 1987). The bowstring is released when audible impetus is received from a device called “clicker”. As the fall of the clicker is an acoustic stimulus, it may evoke a sequence of potentials that can be recorded from the scalp of an archer. Auditory Evoked Potentials (AEPs) occur at different latencies and with various relations to the auditory stimuli. Therefore, the present study aims at investigating the Long-latency Auditory Evoked Potentials in Recurve Archery. Research questions can be stated briefly as follows: (1) What kind of Brain Potentials are Evoked by the Event (Fall of Clicker) during Archery Shooting? (2) Is there any significant difference between the characteristics of the potentials measured in laboratory conditions and during archery shooting? (3) Is there any significant difference between the successful and unsuccessful shots in terms of Auditory Evoked Brain Potentials? (4) Does Archery Shooting session have any effect on Auditory Evoked Brain Potentials? The subjects of the present study were 10 non-archers (N=6 males; N=4 females) for control trials and 15 archers (N=9 males; N=6 females) for archery shooting experiments. All subjects reported normal hearing, had medical histories free of significant neurological problems, and were not taking medication known to affect brain activity. Six different control paradigms have been created. Archery shootings were performed from 18 m that is official competition distance with target face.AEBPs were recorded 200 ms before and 800 ms after the trigger (fall of the clicker) over the vertex during the shots of each subject. Paradigm 1 and 5 was conducted just before and after the archery shooting to test the effect of archery shooting on AEBPs. The hit-area is defined as the rectangle between (x1, y1), (x1, y2), (x2, y1), (x2, y2) and the miss-area is the outer part of the hit-area on the target face. The preliminary analysis has shown that fall of the clicker evokes long latency auditory brain potentials with the latency of 100 msec and 200 msec. These responses are called as N1-P2 components. The means and standard deviations of both N100 and P200 amplitudes were as follows: N100 = 27,73 ± 16,82, P200 = -21,89 ± 20,46. The latencies of given brain responses were also summarized as: N100 = 141,93 ± 41,46; P200 = 211,8 ± 43,97. N1 amplitude was significantly different in archery shooting than that of control conditions (p<0.05) except for trial 3, N1 latency was significantly different than that of trial 2 5 (p<0.05). P2 amplitude is significantly different in archery shooting than that of trial 6 (p<0.05). However, there was no significant difference in terms of P2 latency between archery shooting and control conditions (p>0.05). There was no significant difference between successful and unsuccessful shots in terms of N1-P2 components (p>0.05). An archery shooting session did not create any difference between these components recorded before and after the shot (p>0.05). Having higher N1 amplitudes during archery shooting can be explained by the known multi-component structure of this wave. Different lobes and regions of the brain can be active during the time of the scalp-recorded N1 and simultaneous involvement of several of these areas may be contributing to the electrical field recorded at scalp in the archery shooting paradigm.