Exam 6: The Sensory System

Correct Answer:

Verified

Differentiation between delirium and dementia is essential because many delirium states are reversible, whereas true dementias are essentially irreversible. In clinical delirium there are major behavioral changes not explained by a preexisting dementia. These include an inability to shift or maintain attention to external stimuli, disorganized thinking, perceptual disturbances such as hallucinations, disturbances in the sleep-wake cycle, increased or decreased psychomotor activity, reduced level of consciousness, disorientation, and memory impairment. Symptoms vary from person to person both in severity and progression and develop more rapidly (hours to days) than those of dementia. There are fluctuating periods of rationality over 24 hours rather than the gradual, steady deterioration characteristic of dementia. To further complicate diagnosis, delirium may be superimposed on a dementia or on a major mental illness. Nevertheless, those with delirium do not usually develop dementia. Medications are probably the most common cause of delirium.