Transcranial magnetic stimulation improves naming in Alzheimer disease patients at different stages of cognitive decline

Objective: Word-finding difficulty (anomia) is commonly observed in Alzheimer's dementia (AD). The aim of this study was to assess the effect of repetitive transcranial magnetic stimulation (rTMS) applied to the dorso-lateral prefrontal cortex (dlPFC) on picture naming in 24 probable AD patients with different degrees of cognitive decline. Methods: High-frequency rTMS was applied to the left and right dlPFC during object and action naming in AD patients. A sham stimulation was used as a control condition. Results: Whilst, as previously reported, stimulation to both the left and the right dlPFC improved action, but not object naming in the mild AD group; an improved naming accuracy for both classes of stimuli was found in the moderate to severe group. Conclusions: Repetitive transcranial magnetic stimulation applied to the dlPFC improves naming performance also in the advanced stages of AD. Moreover, in the severe group the effect is not specific for action naming, as in the case of the mild AD group. These findings suggest that rTMS can affect the intrinsic ability of the brain to restore or compensate for damaged function and may represent an useful new tool for cognitive rehabilitation.