Handedness in the mentally handicapped

Area of Science:

• Neuroscience
• Developmental Psychology
• Human Genetics

Background:

• Handedness, the preference for using one hand over the other, is a complex trait.
• Variations in handedness prevalence have been observed across different populations.
• Understanding handedness in individuals with intellectual disabilities is crucial for developmental research.

Purpose of the Study:

• To investigate the prevalence and degree of handedness in normal and mentally handicapped pupils.
• To compare handedness patterns between mentally handicapped pupils with and without Down's syndrome.

Main Methods:

• A cohort of 130 pupils (aged 7-18) was assessed for handedness.
• Handedness was evaluated using 10 distinct performance-based items.
• Statistical analysis was employed to compare handedness prevalence and degree between groups.

Main Results:

• The prevalence of left-handedness was significantly higher in mentally handicapped pupils (26.5%) compared to normal pupils (10.6%).
• The degree of handedness was found to be reduced in the mentally handicapped group.
• No significant differences in left-handedness prevalence or degree were found between mentally handicapped pupils with and without Down's syndrome.

Conclusions:

• Mentally handicapped individuals exhibit altered handedness patterns, including increased left-handedness prevalence and reduced hand preference.
• Down's syndrome does not appear to significantly influence these handedness variations within the mentally handicapped population.
• These findings contribute to the understanding of neurodevelopmental variations in intellectual disabilities.