Cerebral perfusion deficits in age-associated memory impairment. The role of tobacco smoking

Background and aims: Several studies report a high prevalence of memory complaints in the elderly, non-demented population. Since the pathogenesis and diversity of memory impairment in healthy people is still an unresolved issue, we designed our study to ascertain the occurrence of brain abnormalities in Age-Associated Memory Impairment (AAMI) by measuring regional cerebral blood flow (rCBF). Methods: Fifty-three subjects were invited to the case-control study: 26 subjects who fulfilled the AAMI criteria, and 27 controls (age, mean±SD 65.8±7.3 vs 65.5±6.7). rCBF was determined using 99mTCECD SPECT by relative measurements made in the cortical and white matter regions and in the thalamus. Results: The AAMI group vs controls had restricted rCBF in the temporal lobe of the left hemisphere (median; 85.8 vs 87.8, p=0.04), in the thalamus (median; 87.3 vs 89.8, p=0.036) and the frontal white matter (median; right hemisphere 80.0 vs 84.1, p=0.01; left hemisphere 77.7 vs 81.6, p=0.04). AAMI subjects who previously smoked had lower rCBF values in the temporal, parietal, occipital and frontal lobes bilaterally, and poorer memory test results than ex-smoker controls. By contrast, rCBF did not differ between non-smoking AAMI subjects and controls. Conclusions: Compared to controls, AAMI subjects had restricted rCBF. A history of previous smoking could partly contribute to the rCBF differences between these groups. Further studies on failing memory and rCBF in representative cohorts of smoking and non-smoking populations are now needed.