Neonatal frequency discrimination in 250-4000-Hz range: electrophysiological evidence.
OBJECTIVE
The precision of sound frequency discrimination in newborn infants in the 250-4000-Hz frequency range was determined using the neonatal electrophysiological mismatch response (MMR), the infant equivalent of adult mismatch negativity (MMN).


METHODS
The electroencephalogram (EEG) was recorded in 11 full-term sleeping newborn infants mostly in active sleep (67% of the time). Pure tones were presented through loudspeakers in an oddball paradigm with a 800-ms stimulus onset asynchrony (SOA). Each stimulus block contained a standard (p=0.76) of 250, 1000, or 4000Hz in frequency (in separate blocks) and deviants with a frequency change of either 5% or 20% of the standard (p=0.12 of each).


RESULTS
A positive ERP deflection was found at 200-300ms from stimulus onset in response to the 20% deviation from the 250, 1000, and 4000Hz standard frequencies. The amplitude of the response in the 200-300ms time window was significantly larger for the 20% than 5% deviation.


CONCLUSIONS
We observed in newborn infants automatic frequency discrimination as reflected by a positive MMR. The newborns were able to discriminate frequency change of 20% in the 250-4000-Hz frequency range, whereas the discrimination of the 5% frequency change was not statistically confirmed.


CONCLUSIONS
The present data hence suggest that the neonatal frequency discrimination has lower resolution than that in adult and older children data.
Novitski
Nikolai
N
Cognitive Brain Research Unit, Department of Psychology, University of Helsinki and Helsinki Brain Research Center, Helsinki, Finland. nikolai.novitski@helsinki.fi
Huotilainen
Minna
M
Tervaniemi
Mari
M
Näätänen
Risto
R
Fellman
Vineta
V
D000161:Acoustic Stimulation; D000375:Aging / Q000502:physiology; D001306:Auditory Pathways / Q000254:growth & development*; D001921:Brain / Q000254:growth & development* / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006320:Hearing Tests; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010897:Pitch Discrimination / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology