Empathy, defined as the ability to understand others emotions, is a fundamental concept in social interactions. It is a psychological phenomenon involving various separable components : (i) the ability to feel and imagine the emotions, (ii) the ability to adopt the perspective of other people. Several neurological diseases with behavioral disorders may lead to impaired processing of social and/or emotional informations. These pathologies are likely to induce a lack of empathy that may result from impairments at different levels.

The objective is simply to study how others' emotions are understood and how this allows for regulation of personal behavior. This study is being carried out among patients seen for various health problems and who can make behavior changes. This study could help to understand some neurological diseases and thereby to identify them earlier and/or to better differentiate them.

Empathy is a fundamental concept in social interactions, whose function is to understand the emotions felt by others. According to De Waal (2008), it is a multidimensional concept that involves two processes :(i) a system of emotional contagion or affective resonance (the unconscious and automatic sharing of the emotion of others) that establishes the emotional component of empathy, (ii) the ability to take perspective, that is the ability to imagine the subjective world of the other distinguishing oneself from him, forming the cognitive component of empathy.

Several neurological diseases with behavioral disorders may lead to impaired processing of social and/or emotional information. These pathologies are likely to induce a lack of empathy that may result from impairments at different levels.

The main objective of this study is to examine empathy in patients suffering from stroke (various locations with an emphasis on frontal stroke), Fronto-temporal dementia, Alzheimer and Parkinson diseases. The final assessment criterion is the overall score on the scale of empathy.

The patient will firstly receive a medical examination and clinical data are collected (past medical history, clinical neurological examination, diagnosis, description of first symptoms, course, current treatments)and brain imaging data. After checking inclusion criteria, information letter and the consent form will be returned.

The second visit will consist in neuropsychological assessment: general intellectual efficiency, perceptual and visual-constructive abilities, memory, executive and an assessment of behavior and mood from questionnaires The third and final visit will allow passing experimental tests. The experimental part will include the following tests: (1) recognition of emotional facial expressions; (2) tasks of theory of mind ; (3) task of empathy for pain.

A control group will also perform the neuropsychological and experimental tests.

The duration of the study participation for eligible patients and controls will vary according to the delay between each visit (medical, neuropsychological and experimental) and is lower than 3 months. The study will take place from June 2009 to June 2013.

• Number of patients: 320
• Number of controls: 400
• Potential Benefits expected: criteria for early diagnosis and / or differential diagnosis based on the evaluation process of empathy; elaboration of new clinical tools assisting diagnosis.

Inclusion Criteria (Controls):

• being over 18 years old
• speaking French
• in good general health
• affiliated to a welfare state
• given their informed consent in writing

Inclusion Criteria (Patients):

• 18 to 85 years old
• French speaker
• affiliated to a Welfare state
• written consent
• MMSE> 20
• no alexia, agraphia or illiteracy
• absence of diseases that can interfere with cognition (neoplasia, chronic alcoholism ...) of current or past neurological diseases other than those which justified the support nervous system (meningitis, encephalitis, brain injury, developmental disorders, deficits sensory or motor, epilepsy requiring treatment today ...), or of psychiatric disorder (except depression treated)

Exclusion Criteria (controls):

• pathological MMSE score
• insufficient acquisition of the alphabet
• reading, writing, arithmetic
• the presence of a visual deficit or hearing deficit disturbing the tests, paralysis of the dominant hand
• the presence of brain pathology interfering, neurological or psychiatric history

Exclusion Criteria (Patients):

• difficulties in reading, writing or illiteracy
• diseases that can interfere with cognition (neoplasia, chronic alcoholism ...)
• current or past neurological diseases other than those which justified the neurological consultation, Psychiatric pathology (except depression treated)