A 47-year old male is brought to your office by his wife for psychological evaluation. She reports that for the last 6 months, she has been noticing changes in her husband’s personality, behavior and speech. There is a gradual decline in his memory. He has become more suspicious of her, washing hands repeatedly, checking the doors and windows more than usual. He is struggling to find the right words to express himself. He is undressing in public places and cracking inappropriate jokes. In the last month, he had fallen several times, become incontinent of urine, and had difficulties with basic activities of daily living such as brushing his teeth and dressing. He developed a voracious appetite, eating 4-5 pieces of cheesecake at a time. A magnetic resonance imaging scan of the brain demonstrated enlarged sulci and ventricles and cortical and white matter atrophy of the frontal lobes and temporal lobes. What is the pathological hallmark of this disorder?
