Laterality judgement task in people affected by leprosy

Leprosy is characterized by the involvement of the skin and peripheral nerves. This involvement can be presented by sensory, motor, and autonomic changes. Impaired hand sensibility may decrease the information that reaches specific areas of the central nervous system, resulting in changes in perception. During the laterality judgment task (or the ability to distinguish between left and right), an indivudual observes an image of a hand, performs a mental body rotation and compares the image with their body representation in the brain, which requires integrating sensory inputs with the sensory and motor systems.

Objective:
This study compared the performance on the left/right judgment task between people with nerve damage caused by leprosy and asymptomatic controls.

Materials and Methods:
Patients performed a task using the software Recognise®. Results were compared with those of a control group, comprising healthy individuals.

Results:
The study included 33 participants, of whom 20 were patients with leprosy (patient group) and 13 were healthy individuals (control group). The mean rate of correct responses by the patient group was 70% for the right hand and 62% for the left hand. The mean rate of correct responses by the control group was 83.4% for the right hand and 83.8% for the left hand.

Conclusion:
Patients demonstrate changes in body configuration, resulting in an influence of proprioceptive information on the subject’s current posture. These results may imply the presence of changes to the representation of the hand area in the brain’s sensory cortex.