Cg. Fowler et Cm. Mikami, EFFECTS OF NOISE BANDWIDTH ON THE LATE-POTENTIAL MASKING LEVEL DIFFERENCE, Electroencephalography and clinical neurophysiology, 84(2), 1992, pp. 157-163
The masking level difference (MLD) is a psychoacoustic phenomenon deri
ved from the subtraction of S-pi-No thresholds (signals pi-radians out
of phase and noise in phase at the two ears) from SoNo thresholds (si
gnals and noise in phase at the two ears). The purpose of this study w
as to determine if the MLD derived from the late components (P1, N1, P
2, N2) of the auditory evoked potentials was a physiological correlate
of the behavioral MLD. Subjects were 15 young adults with normal hear
ing. Comparisons were made between behavioral and late potential thres
holds to 500 Hz stimuli in So and S-pi conditions in quiet, and to 500
Hz stimuli in SoNo and S-pi-No conditions in narrow band (50 Hz) and
wide band (600 Hz) noise. No significant differences were seen for beh
avioral or late-potential thresholds to So and S-pi conditions. The S-
pi-No threshold was significantly lower than the SoNo threshold, yield
ing an MLD for both the behavioral and physiological responses. The ma
gnitudes of both the behavioral and late-potential MLD were larger wit
h the narrow band noise than with the wide band noise. Evidence, there
fore, is provided that the late-potential MLD reflects similar process
es as are responsible for the behavioral MLD.