A comparative study of simple auditory reaction time between male congenital full blind and sighted control

Huge amount of interest has been created regarding compensatory increase in other sensory modalities in blind due to loss of vision by so called Cross Modal Plasticity theory. In order to review its impact on auditory compensation in blind we attempted to study simple auditory reaction time in male congenital blind and compared with male sighted control's simple auditory reaction time.

25 male congenital full blind and 25 male sighted control full filling inclusion criteria were presented with 3000 Hz single tone sound via headphone randomly for 20 times and were instructed to press spacebar as soon as they hear sound. Time interval between sound presentation and pressing of spacebar was recorded by computer using Direct RT software. Other preliminary data were inquired before starting the test.

Male congenital full blind were having faster reaction time compared to sighted control in significant proportions (p<0.05). Right handed individuals (irrespective of blind or sighted) were having faster reaction time compared to left handed though it was not of significant magnitude. Negative correlation was found between BMI and reaction time i.e. Higher BMI Lesser simple auditory reaction time

Faster reaction time in congenital blind is proposed to be due to use of occipital cortex for auditory processing due to compensatory reorganization of neuronal circuitry in brain. Though further evaluation of other facets of auditory modality can give clearer picture of this cross modal plasticity.