[Effects of monaural and binaural stimulation on middle latency auditory evoked responses].
BACKGROUND
Middle latency evoked potentials include a series of evoked responses which encompass/include myogenic potentials (which translate the existence of sonomotor reflexes), and others which are clearly of neurogenic origin. The latter are the most useful from the clinical point of view.


OBJECTIVE
To evaluate the effects of monoaural (MA) and binaural (BA) stimulation on middle latency auditory evoked potentials.


METHODS
We studied 15 healthy people, aged between 18 and 52 years, in whom Cz recording electrodes had been fitted to both short-circuited external ears with Fpz as earth. The stimuli used were alternate clicks of condensation and rarefication of 90 dBHL, first BA and them MA. The auditory evoked response from the brain stem was also recorded.


RESULTS
We found more stability of most of the components evaluated during biauricular stimulation. All subjects had Pa waves and 93% had Pb waves. Statistically significant differences were only found for the amplitude of Po and Pa (BA against RE) (Wilcoxon test, p < 0.05).


CONCLUSIONS
The use of BA stimulation to obtain middle latency evoked potentials is more useful for study of the more rostral parts of the auditory path, since its components are more stable.
Báez-Martín
M M
MM
Laboratorio de Neurofisiología Clínica, Centro Internacional de Restauración Neurológica, CIREN, Ciudad de la Habana, Cuba. cineuro@neuro.sld.cu
Cabrera-Abreu
I
I
D000293:Adolescent; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000502:physiology; D012022:Reflex, Acoustic / Q000502:physiology