This 58-year-old right-handed man presented with a 3-year history of personality changes and imbalance. His family first noticed he was more withdrawn from social activities and seemed to care less about his appearance. In addition, he was not as affectionate as before and would often make inappropriate comments (e.g., telling people they were overweight). After a recent death in the family, he did not seem to be emotionally affected. More recently, he became more disorganized, which affected his work performance. His gait slowed, and he started to fall frequently. Despite all these changes, he did not seem to be bothered by his symptoms. On neurological examination, he exhibited a resting tremor of the left leg as well as symmetric bradykinesia and upward vertical gaze limitation. His gait was mildly wide-based and unstable, with quick turning (Video 15.1). When asked about family history of neurological disease, he reported his father recently died with Parkinson disease. In addition, out of his five siblings, two older brothers had been diagnosed with dementia and a younger sister with late-onset schizophrenia. His neuropsychological evaluation revealed prominent deficits in executive function, including response inhibition (i.e., ability to suppress inappropriate responses), fluency (i.e., producing words in a limited amount of time), and set-shifting (i.e., switching between different tasks).