Analyzing the amplification of Auditory sensation in visually impaired individuals and comparison with normal individuals

Background It is commonly believed that if a person loses one of their basic senses like sight or hearing, other senses will be amplified to compensate the loss. It has been proven that this amplification does indeed help the person up to an extent, but this increase in the senses as compared to other individuals, who have all senses intact, has not been quantified. Aim To estimate and compare Auditory Acuity between visually impaired and normal people To calculate the amount of amplification in the Auditory sense in the visually impaired individuals in compared to Normal Individuals Methodology A Cross Sectional Case-control Pilot Experimental Study was carried out using a method that has been developed by the authors, wherein a pure tone sound at a specific intensity was brought inwards towards the subject from multiple directions and the distance was measured where the participant could hear the sound and was noted. The same experiment was carried out in Normal Individuals with normal 6/6 vision and these measurements were compared. Positon of nose in respect to the direction of sound source was used to denote the results in angles made by the two. A pure tone of 256 Hz, of 30db was used as the sound source and the distance from the subject was measured in meters. Results Out of total 60 individuals in the study, 45 had some degree of blindness. In both groups, the highest sensitivity is at 0° followed by 45°-315°, then comes 90°-270° and 135°-215° to put nose position of 180° at least amount of sensitivity. A 10% amplification in the distance is present between any and all type of visually impaired individuals and normal individuals whereas totally blind individuals have around 20% amplification compared to normal individuals in the distance to appreciate the sound. Conclusion A visible difference can be seen in the distance where a total blind person can hear, which is higher than the distance at which a normal individual can hear. High loss of vision, low loss of vision and one eye blind individuals come in the range between these two. Although, the results are not statistically significant, they are clinically present, and a with a larger sample size, a better assessment of this amplification can be done.