New Meta-Analyses Explores the Relationship between Handedness and Stuttering

King George VI might be history’s most famous stutterer. He was also a natural left-hander.

A new study has delved into the intriguing connection between handedness and stuttering, shedding light on this neurodevelopmental puzzle. The study, led by Dr. Marietta Papadatou-Pastou, Assistant Professor of Neuropsychology at the National and Kapodistrian University of Athens, has recently been published in Neuropsychology Review, adding a valuable contribution to our understanding of neurodevelopmental disorders.

Reduced hemispheric asymmetries and atypical handedness (non-right, left-, or mixed-handedness) have long been associated with neurodevelopmental disorders, including autism spectrum disorder and attention deficit hyperactivity disorder as well as several psychiatric conditions. However, the connection between stuttering and handedness had not been studied in the context of a meta-analysis to date.

In a comprehensive series of meta-analyses, researchers from Greece and Germany explored the levels of hand preference in individuals who stutter compared to non-stuttering controls. The study was based on 52 identified studies with 2,590 individuals who stutter and 17,148 controls.

“We did not find evidence of a mixed-handedness difference or a difference in mean handedness scores,” the researchers reported. However, evidence did emerge concerning left-handedness and non-right-handedness, albeit not robust.

Dr. Marietta Papadatou-Pastou stated, “Our findings do not allow for firm conclusions to be drawn on whether stuttering is associated with reduced hemispheric asymmetries, at least in terms of their behavioral manifestation, i.e. handedness. Future research should consider disorder-specific approaches, as the evidence suggests that the connection varies between different conditions.”

Stuttering, characterized by frequent speech repetitions or hesitations, affects approximately 1% of children and adolescents and 0.2% of women and 0.8% of men worldwide. The condition has high heritability estimates between 70 to 80%, and treatment options often provide insufficient evidence for success.

The study has implications for clinical practice and education. Atypical handedness should not be considered a central risk factor for stuttering, according to the researchers. Parents need not be alarmed if their child exhibits non-right-handedness in the context of stuttering signs.

For more information or to access the complete academic paper, please visit https://doi.org/10.1007/s11065-023-09617-z.

“Hand preference in stuttering: Meta-analyses” is published in the Neuropsychology Review

DOI: https://doi.org/10.1007/s11065-023-09617-z.