White matter hyperintensities affect transcranial electrical stimulation in the aging brain.

BACKGROUND

White matter hyperintensities (WMH) are estimated to occur in greater than 63% of older adults over the age of 60 years. WMH identified in the T2-weighted FLAIR images can be combined with T1-weighted images to enhance individualized current flow models of older adults by accounting for the presence of WMH and its effects on delivered tES current in the aging brain.

METHODS

Individualized head models were derived from T1-weighted images of 130 healthy older adults (mean = 71 years). Lesions segmented from FLAIR acquisition were added to individualized models. Current densities were computed in the brain and compared between models with and without lesions.

MAIN RESULTS

Integrating WMH into the models resulted in an overall decrease (up to 7%) in median current densities in the brain outside lesion regions. Changes in current density and total lesion volume was positively correlated (R = 0.31, p < 0.0001).

CONCLUSIONS

Incorporating WMH into individualized models may increase the accuracy of predicted tES current flow in the aging brain.