Handedness of healthy elderly and patients with Alzheimer's disease.

Purpose/Aim of the study: Research has suggested decreasing proportions of non-right handers in older age groups and reduced incidence of non-right handedness among individuals with Alzheimer's disease (AD). We hypothesized that healthy elderly individuals would have a higher proportion of non-right handers than individuals with AD and that the proportion of non-right handers would decrease with increasing age. Further, we investigated whether the proportions of non-right handers differed between those with early and late onset of AD.Materials and

Methods

Two-hundred and fifty-six healthy elderly and 182 individuals with AD served as participants. Hand dominance was recorded based on side of writing during testing and self-report. We analyzed proportions of right handers and non-right handers for three age ranges (≤ 69, 70 - 79, and ≥ 80 years). A second analysis focused on the proportions of right and non-right handers among patients with AD classified as either early or late disease onset.

Results

Handedness proportions did not differ between the controls and ADs. For AD but not for controls, there was a trend towards reduced proportions of non-right handers with increasing age. Early onset AD was associated with a larger proportion of non-right handers compared to those with late onset AD.

Conclusions

Results did not support a trend of decreasing non-right handedness with increasing age in controls, but did provide support for such a trend in individuals with AD. The results provided support for the hypothesis of increased incidence of non-right handedness in early onset vs. late onset AD.