Amputation may result in altered perception around hands

Washington, Jan 7 (ANI): A new study from the Hebrew University of Jerusalem has shown that hand amputation might alter the spatial perception around our hands.

The space within reach of our hands - where actions such as grasping and touching occur - is known as the "action space."

The research team has found amputation of the hand results in distorted visuospatial perception (i.e., figuring out where in space objects are located) of the action space.

During the study, participants with either left- or right-hand amputations were instructed to look at a central cross on a screen as two white squares were briefly shown to the left and right side of the cross.

They had to indicate which of the squares was further away from the cross.

The results showed that hand amputations indeed affected visuospatial perception.

When the right square was slightly further away from the centre, participants with right-hand amputations tended to perceive it as being at the same distance from the centre as the left square.

This suggests that these volunteers underestimated the distance of the right square relative to the left.

On the other hand, when the left square was further away, participants with left-hand amputations perceived both squares as being equally far away from the centre - these participants underestimated the left side of near space.

However, when the volunteers were seated farther away from the screen, they were more accurate in judging the distances, indicating that hand amputations may only affect perception of the space close to the body.

The findings suggest that losing a hand may shrink the action space on the amputated side, leading to permanent distortions in spatial perception.

"This shows that the possibility for action in near space shapes our perception - the space near our hands is really special, and our ability to move in that space affects how we perceive it," said researchers.

The study appears in Psychological Science, a journal of the Association for Psychological Science. (ANI)