Tc-99m HMPAO brain SPECT findings in mild and moderate Alzheimer's disease: Correlation with event related potentials

• Published in: Journal of the neurological sciences 2005-07, Vol.234 (1), p.47-53
• Main Authors: Gungor, Hulya Aydin, Yildiz, Akin, Aydin, Funda, Gungor, Firat, Boz, Adil, Ozkaynak, Sibel
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Alzheimer Disease - diagnostic imaging; Alzheimer Disease - metabolism; Alzheimer Disease - physiopathology; Alzheimer's disease; Biological and medical sciences; Brain Mapping; Case-Control Studies; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiopathology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dementia; Electrodiagnosis. Electric activity recording; Electroencephalography - methods; Event related potentials; Evoked Potentials - physiology; Female; Functional Laterality; History, Ancient; Humans; Image Interpretation, Computer-Assisted - methods; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Nervous system; Neurology; P300; Prospective Studies; Radiopharmaceuticals - pharmacokinetics; Reaction Time - physiology; SPECT; Statistics, Nonparametric; Tc-99m HMPAO; Technetium Tc 99m Exametazime - pharmacokinetics; Tomography, Emission-Computed, Single-Photon
• ISSN: 0022-510X; 1878-5883
• DOI: 10.1016/j.jns.2005.03.034

We investigated whether brain SPECT findings show any differences between patients with mild and moderate Alzheimer's disease (AD) and to compare results with event related potentials (ERPs). Twenty-two patients with mild to moderate AD diagnosed according to NINCDS-ADRDA criteria and 10 age-matched control subjects were included in this prospective study. All subjects underwent ERP recordings and Tc-99m HMPAO brain SPECT study. Cortical perfusion index (CPI) was calculated as the ratio of cortical activity to the cerebellum activity. CPI was found to be statistically lower in bilaterally posterolateral temporal cortex and precuneus in the moderate AD compared to the control group. There was no statistically significant difference between the mild AD and control groups for CPI in any cortical areas. The mean P300 latency was statistically prolonged in the mild and moderate AD compared to the control group. In addition, in moderate AD P300 latency was longer than in mild AD. While the mean P300 amplitude was statistically reduced in moderate AD compared to the control and mild AD, there was no statistically significant difference between the mild AD and control groups. There was a strong negative correlation between P300 latency and CPI in the right and left precuneus in the moderate AD group. The present study suggested that Tc-99m HMPAO SPECT study is the more appropriate technique for patients with moderate AD rather than mild AD. Our results indicated that alterations in ERPs, especially prolongation of P300 latency could be a finding that occurred earlier than the deterioration in cerebral blood flow. We thought that precuneus is closely related to cognitive function and may have an important role in the pathophysiology of AD.