Although acetyl-L-carnitine (ALC) treatment may have beneficial effects on Alzheimer's disease (AD), its underlying neural correlates remain unclear. The purpose of this study was to investigate cerebral perfusion changes after ALC treatment in AD patients using technetium-⁹⁹m hexamethylpropylene amine oxime single photon emission computed tomography (SPECT).

A total of 18 patients with early AD were prospectively recruited and treated with ALC at 1.5 g/day for 1.4±0.3 years. At baseline and follow-up, brain SPECT, Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), Global Deterioration Scale (GDS), and Neuropsychiatric Inventory (NPI) were used to assess participants. After ALC administration, changes in brain perfusion, severity of dementia, cognitive performance, and neuropsychiatric disturbances were examined.

After ALC administration, changes in scores of MMSE, CDR, GDS, and NPI were not statistically significant ( p >0.05). Voxel-wise whole-brain image analysis revealed that perfusion was significantly ( p <0.001) increased in the right precuneus whereas perfusion was reduced in the left inferior temporal gyrus ( p <0.001), the right middle frontal gyrus ( p <0.001), and the right insular cortex ( p =0.001) at follow-up.

Although previous studies have suggested that AD patients generally demonstrate progressive deterioration in brain perfusion and clinical symptoms, this study reveals that the perfusion of the precuneus is increased in AD patients after ALC administration and their cognitive and neuropsychiatric symptoms are not aggravated. Further studies are warranted to determine the potential association between perfusion increase in the precuneus and clinical symptoms after ALC treatment in AD patients.