A standardized questionnaire completed by a caregiver designed to assess behavioral changes characteristic of frontal lobe dysfunction, especially in frontotemporal dementia (PTD). It contains 24 items covering both negative symptoms (apathy, indifference, inflexibility) and positive symptoms (disinhibition, perseveration, irritability). The caregiver assesses the frequency and severity of each manifestation based on the patient’s usual behavior. FBI is used to diagnose, track disease progression, and evaluate treatment efficacy in clinical and research practice.