Int. Adv. Otol. 2009; 6(1); 83-88

Comparison of Middle Latency Auditory Evoked Potential Results of Congenitally Blind, Partial Vision Deficiency to Normal Vision Aquity Subjects
Nevma Madanoglu, Hulya Devrilmez
Department of Audiology, Marmara University Medical School, Istanbul, Turkey  znmadanoglu@marmara.edu.tr

Objective: The auditory abilities of “congenitally blind”, “partial vision deficiency” and “normal vision” groups were tested using
middle latency response test which is an auditory evoked potential test reflecting the primary and secondary auditory area
activities. The objective of the Auditory Middle Latency Response Test was to find out differences in wave latency and
amplitude among the groups.

Materials and Methods: Eleven congenitally blind people composed the first group, the second group included 10 subjects
with “partial vision deficiency”. Thirteen subjects with normal vision were in the third group. The age range of the subjects were
between 18-30 years. All the participants had normal hearing. Auditory Middle Latency Response (AMLR) test was applied to
all subjects and AMLR results were recorded from Fz and Cz electrode localizations.

Results: In the Cz recordings, there was a significant difference between Pa and Nb wave latency values among the groups.
Average Pa wave latency of the first group was longer than that of the third group. Average Nb wave latency of the first group
was longer than Nb wave latency of the second group. In the Fz recordings, average Pb wave latency of the first group was
significantly longer than that of the second group and third group. In Cz and Fz recordings, there were no significant differences
between Po-Na, Na-Pa, Pa-Nb, Nb-Pb amplitudes among the groups.

Conclusion: Results of Cz and Fz recordings indicated longer Pa and Nb wave latency in the congenitally blind group than in
the other groups. No significant amplitude difference was present among the groups.