Nicotinic I-123-5IA-85380 Single Photon Emission Computed Tomography as a Predictor of Cognitive Progression in Alzheimer's Disease and Dementia With Lewy Bodies

Objective: To investigate normalized I-123-5-Iodo-3[2(S)-2-azetidinylmethoxy] pyridine (5IA-85380) single photon emission computed tomography (SPECT) imaging, a marker for the alpha 4 beta 2 nicotinic receptor, as a predictor of cognitive progression in Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). Methods: Thirty-one patients with dementia (16 patients with AD and 15 patients with DLB) underwent I-123-5IA-85380 SPECT scanning. Image analysis was performed using statistical parametric mapping (SPM2), which involved spatial preprocessing of scans to standard Montreal Neurological Institute space and intensity normalization of each image to its mean global brain activity. Results: Regression analysis revealed that reduced normalized I-123-5IA-85380 uptake in left superior, middle, and inferior frontal gyri and prepost central and anterior cingulate regions significantly correlated with decline in executive function in a pooled group comprising AD and DLB. Conclusion: The findings, although preliminary, suggest that the cholinergic system may be more involved in neurodegenerative processes affecting some cognitive processes more than others, as such, this procedure may be useful for increased understanding of the pathophysiological mechanisms responsible for neurodegeneration.(Am J Geriatr Psychiatry 2010; 18: 86-90)