<prompt> A 70-year-old man presents with ho prosopagnosia, loss of memory, 3rd person hallucinations since 1 month. On examination deep tendon reflexes are increased, mini-mental examination score is 2030. What is most likely diagnosis?Dissociative amnesiaSchizophreniaAlzheimers diseasePsychotic disorder  <response>: The presence of loss of memory, prosopagnosia difficulty in identifying face in a 70 year old man is quite suggestive of Alzheimers disease. Third person auditory hallucinations are usually seen in schizophrenia; however they can be present in Alzheimers disease too. Fuher on examination, deep tendon reflexes are increased, which again can be seen in late stage of Alzheimers disease. Finally MMSE score below 24 seals the diagnosis. 