<prompt> A 70 yr old man presents with 10 prosopagnosia loss of memory, 3rd person hallucination since 1 month. On examination deep Tendon reflexes are increased, minimental examination score is 2030. What is most likely diagnosis:Dissociated DementiaSchizphreniaAlzheimers diseasePsychotic disorder  <response>: C i.e. Alzheimers disease Duration of 1 month only, is enough to rule out schizophrenia, in which duration should be at least 6 months In psychiatric disorders like schizophrenia psychosis, there may never be organic symptoms like increased tendon reflexes. Features of Alzheimer dementia are Memory impairment without impairment of consciousnessQ AgnosognosiaQ Unware of his problem Prosopangosia difficulty in identifying known faces Focal neurological signs ex assymetrical hyper-reflexia or weaknessQ Primitive reflexes ex grasp, snout, suck, palmo-mental, tonic foot reflexes Frontal lobe signs Aphasia language disturbance Apraxia impaired ability to carry out motor activities despite intact motor function Agnosia failure to recognize or identify objects despite intact sensory function Disturbance in executive functioning i.e. planning, organizing, sequencing, abstracting 