Background: Understanding the effects of visual loss on remaining senses has been a matter of interest since long. Neuroplasticity in the form of cross-modal plasticity occurs to compensate for the loss of function and to enhance remaining functions in the event of sensory deprivation. In congenitally blind individuals, auditory localization tasks can activate the visual cortex. Studies have shown that blind subjects perform as well or even better than normal controls with auditory stimuli.
Objectives: To compare the auditory evoked potentials in congenitally blind individuals with those of normal subjects so as to look for any compensatory increased activity in auditory functions.
Materials and Methods: Auditory evoked potentials were recorded in 33 normal subjects and 37 congenitally blind subjects using a single fiber electromyography. Recording was done in both ears by giving clicks into test ear. Latencies, amplitudes, and waveforms were recorded.
Result: A significant decrease (p < 0.05) in latencies of left I and V wave was seen both ipsilateral and contralateral. One-way ANOVA showed a significant difference in the mean between the two groups.
Conclusion: A compensatory neural reorganization may occur in blind individuals which may be influenced by corticofugal connections with the auditory system.
Key words: Auditory evoked potentials, cross-modal plasticity, congenital blindness, latencies
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