SPECT Findings on Psychiatric Symptoms in Alzheimer's Disease

ABSTRACT

OBJECTIVES: The course of Alzheimer's disease is often complicated by psychiatric symptoms including depression, delusion and hallucination. And these psychiatric symptoms may be due to neuropathological changes of the disease itself. This study examined whether psychiatric symptoms in Alzheimer's disease are associated with cerebral perfusion using single photon emission computed tomography (SPECT). METHODS: Supratentorial transaxial perfusion measurements were obtained in frontal, anterior temporal, posterior temporoparietal and occipital cortical areas in both hemispheres, in a baseline population of 29 mild to moderately impaired AD patients. We interviewed all the patients and their primary caregivers to assess their current and past psychiatric functioning. To compare the SPECT findings, all the patients were divided into two groups by presence of depression, delusion, hallucination and illusion, of which symptoms were explored separately. RESULTS: The patients with hallucination had hypoperfusion of both the posterior temporoparietal and the occipital regions of interest, compared with scans of the patients without hallucination. And in other symptom profiles, there was no difference in SPECT findings between the patients with symptoms and without symptoms. CONCLUSION: Psychotic patients with Alzheimer's disease had a pattern of cerebral perfusion deficits, which is different from that of nonpsychotic patients. This finding suggests that specific patterns of cerebral dysfunction probably be related to the specific psychiatric symptoms in Alzheimer's disease.