This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organic Mental Disorders, Subject name: Psychiatry
Delirium and dementia can be differentiated by: 
Select and explain. 
A. Loss of memory, B. Apraxia, C. Delusion, D. Altered sensorium
D: Altered sensorium
Answer: D: Altered sensorium 
Explanation: Please remember that the hallmark of delirium is disturbance of consciousness (altered sensorium) whereas in dementia, there is no disturbance of consciousness. DELIRIUM DEMENTIA Onset Sudden onset Insidious onset Consciousness Disturbed NO Disturbance Course Fluctuating Course Progressive course