Study of Social Behavior and Emotion in Frontotemporal Dementia, Alzheimer's Disease and Controls

Inclusion Criteria (FTD or AD patients): * The core diagnostic features of bvFTD or NINCDS-ADRDA criteria for clinically probable AD * Mild-moderate cognitive and functional severity defined as an MMSE \>/=10 and a CDR \</=2.0 * Able to understand and complete procedures and to take part in the tests by hearing and understanding instructions and by seeing the stimuli to be responded to * Willingness and ability to provide informed consent; Informed consents from caregiver and patient * English speaking, having acquired English prior to age 13 and using it as primary language * Minimally impaired language (language and semantics tests cut-off scores) * Medically stable (defined as absence of medical illness that would interfere with the subject's ability to understand and participate in study procedures) * Absence of a neurological or psychiatric illness other than bvFTD or clinically probable ADB * Absence of cortical infarction, other cortical lesion, or significant subcortical lesion on MRI of brain * Absence of potentially confounding medications, particularly those with effects on the peripheral nervous system, cardiovascular agents, and β-blockers * Presence of a caregiver who can facilitate participation in this project. (see below) Where there is more than one caregiver, every effort is made to designate the closest relative as the main caregiver. Exclusion Criteria (FTD or AD patients): * Violation of any of the criteria above. Inclusion Criteria (Study Partners/Caregivers): * Personally visit and interact with the subject at least one time each week for one hour. * Accompany the subject to each visit. * Provide opinions about the subject's thinking (i.e., memory, language, problem-solving ability), daily activities (i.e., dressing, hygiene, mobility, household chores, and hobbies), and behavior (i.e., mood, sleep patterns, appetite, participation in social interactions). * Share personal information including feelings of distress about the subject's behavior or feelings of burden by caregiving responsibilities. * Read, understand and speak English fluently in order to ensure comprehension of informed consent form and informant-based assessments of the subject. * Provide full written informed consent on his/her own behalf prior to the performance of any protocol-specific procedure. * In the opinion of the investigator, the study partner will be compliant with the protocol and have a high probability of completing the study Exclusion Criteria (Study Partners): * Violation of any of the criteria above. Inclusion Criteria (Control Participants): * Denies neurological or psychiatric illness. * Not currently a caregiver for a dementia patient (for at least one year). * Does not take potentially confounding medications, including most of those with effects on the central nervous system and peripheral nervous system, cardiovascular agents, and β-blockers. The use of these medications will be assessed during a telephone screening. Exclusion Criteria (Control Participants): * Violation of any of the criteria above.