Der einflu� von intensit�t und dauer der Beschallung auf den Off-Effekt des akustisch evozierten potentials

Intensity effects of the auditory evoked brain response to stimulus onset and cessation

“…Components C, D, and E ofthe ON EBR have clearly evident counterparts in G, H, and I of the OFF EBR. The finding that F was difficult to detect supports the data of Onishi and Davis (1968) , who indicated a difficulty in detecting components comparable to F and G. The OFF EBR is of smaller amplitude than the ON EBR, supporting the data of Onishi and Davis (1968), Spychala et al (1969) and Johannsen et al (1972).…”

“…This slope difference also suggests that the ON and OFF responses may be generated from different, though not necessarily exclusive, physiological mechanisms. If the two responses were generated by the same physiological system, one would expect similar ON and OFF EBR slopes within an individual S. The shorter response latency for G (30-90 msec) as compared to C (95-110 msec) supports the data of Onishi and Davis (1968) and Johannsen et al (1972) and further suggests that the ON and OFF responses are functions of separate physiological mechanisms with different response latencies. Under the conditions ofthis study, latency of the OFF response is not as sensitive a measure of intensity change as amplitude is.…”

“…Davis and Zerlin (1966) have suggested that a possible interaction between ON and OFF responses could account for the slight amplitude increase they found for the ON response for durations of less than 30 msec. Johannsen et al (1972) have also mentioned the possibility of ON and OFF interactions for short-duration stimuli. A study of ON and OFF EBR interactions, systematically varying stimulus duration and intensity, may help to resolve the question of to what extent the ON and OFF responses share the same physiological mechanism.…”

“…More recent studies compare the ON and OFF measures and show some differences. The latency of the OFF response has been reported to be similar to that of the ON response (Spychala, Rose, & Grier, 1969;Onishi & Davis, 1968), but there is some evidence that at least one component of the OFF response may have a shorter latency (Onishi & Davis, 1968;Johannsen, Keidel, & Spreng, 1972). Amplitude comparisons have shown the OFF response to be smaller than the ON response (Spychala et al, 1969;Onishi & Davis, 1968;Johannsen et al, 1972).…”

“…A general trend toward increasing amplitude and decreasing latency of the OFF response has been suggested by some authors (Onishi & Davis, 1968;Johannsen et al, 1972). Only three or four stimulus intensities were used in each of these studies.…”