Combined Effect of Repetitive Transcranial Magnetic Stimulation and Cognitive Rehabilitation on Working Memory of Patients with Chronic Stroke

Working memory is one of the cognitive aspects that may be damaged in patients suffering from a stroke. According to evidence, repetitive Transcranial Magnetic Stimulation (rTMS) and cognitive interventions could affect cognitive function in healthy individuals or patients with neurological diseases.

This study aimed to evaluate the combined effect of high-frequency rTMS in the left Dorsolateral Prefrontal Cortex (DLPFC) region of the brain and cognitive rehabilitation on the working memory of stroke patients.

In this double-blind, randomized clinical trial with a pretest-posttest design, 18 post-stroke chronic patients aged 55 to 75 years were randomly divided into two experimental and control groups. The working memory score was measured using the N-back test in the two groups before the interventions. Then, both groups participated in rTMS intervention sessions, except that in the control group, changing the coil angle prevented the waves from reaching the brain. The rTMS interventions were performed for each patient in 15 sessions of six minutes, three days a week. In addition, both groups received computer-based cognitive rehabilitation therapy immediately after each rTMS session for 30 to 40 minutes. These practices included working memory rehabilitation in Captain's Log software used at the adult level. Each level had 15 steps, and the difficulty of the exercises increased with increasing steps. Finally, the working memory was remeasured after the intervention sessions.

The use of rTMS on the left DLPFC region significantly improved the working memory of stroke people in the experimental group compared to the control group (P = 0.027). In addition, the difference before and after the interventions in both groups was significant for this variable (P < 0.001), which indicates the positive effect of cognitive rehabilitation on reducing cognitive problems.

Although cognitive rehabilitation using software is effective on working memory, using rTMS along with cognitive rehabilitation in the left DLPFC area has a more significant effect on improving working memory in people with chronic stroke.