TMS suppression of right pars triangularis, but not pars opercularis, improves naming in aphasia

This study sought to discover if an optimum 1 cm2 area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1 Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions.

► We studied chronic aphasia patients with one stroke in the left hemisphere.
► We sought optimal brain area to treat with slow, Transcranial Magnetic Stimulation.
► The optimal cortical area in the undamaged (right) hemisphere was pars triangularis.
► This improved accuracy and speed in naming pictures.
► Results have application for enhanced rehabilitation in stroke patients with aphasia.