Repetitive transcranial magnetic stimulation (rTMS) to the dorsolateral prefrontal cortex (DLPFC) can improve the difficulties in verb naming experienced by many patients with Alzheimer's disease, Italian researchers report.

By contrast, and as the authors hypothesized, this treatment does not improve noun naming, according to the findings reported in the Archives of Neurology for November. The left prefrontal and parietal regions of the brain have been linked to verb-specific responses, while the inferior temporal lobe appears to play a role in noun-specific responses.

In an earlier study, rTMS to the DLPFC was shown to improve verb naming in young subjects. Dr. Carlo Miniussi, from the University of Brescia, and colleagues investigated whether this treatment also improved naming in patients with Alzheimer's disease.

The present study involved 15 patients with probable Alzheimer's disease who were treated with high frequency rTMS or sham rTMS to the left and right DLPFC while participating in object and action naming.

Consistent with previous research, rTMS to either the left or the right DLPFC significantly improved action naming compared with sham rTMS. While rTMS to this region, particular on the right side, improved object naming to a greater extent than did sham rTMS, the difference was not statistically significant.

"The present findings provide direct evidence for a causal role of the DLPFC in action naming. The same procedure, which in young control subjects shortened naming latency, resulted in an increased number of correct responses in patients with anomic Alzheimer's disease," the researchers state.

"Repetitive transcranial magnetic stimulation may be worth testing as a novel treatment approach for language deficits, based on the modulation of a distributed, bihemispheric language network," Dr. Miniussi's team concludes.