Repetitive Transcranial Magnetic Stimulation Improves Executive Function and Music Rhythm
Abstract
Although temporoparietal lobe dysfunction in the form of impaired retrieval of learned information is the cardinal symptom of Alzheimer’s dementia, frontal lobe dysfunction causes much caregiver distress and is often the presenting symptom among highly educated individuals (1). Perhaps the high educational achievement of this patient population masks the “typical” Alzheimer’s presentation, adding to clinical confusion. The frontal lobe dysfunction is often manifested as decline in motivation (apathy), cognitive rigidity and inability to perform sequential tasks (executive dysfunction), and poor insight. These atypical presentations are difficult to diagnose and manage. Many patients retain semantic memory, but their symptoms do not respond to conventional Alzheimer’s treatments, often resulting in significant caregiver burden. We present a case of a patient with a known history of Alzheimer’s dementia who presented with new-onset music rhythm perception impairment. On testing, he was found to have prominent executive dysfunction, apathy, and poor insight. Because most of his presenting symptoms were frontal lobe in origin, an off-label trial of repetitive transcranial magnetic stimulation (rTMS) to the left dorsolateral prefrontal cortex (DLPFC) using the refractory depression protocol was conducted. We examine whether rTMS improved music rhythm in this patient, and we present results after 12 consecutive rTMS sessions.