Early Diagnosis of Alzheimer's Disease and Parkinson's Disease Associated with Dementia Using Cerebral Perfusion SPECT

Abstract

Background: Since patterns of cognitive dysfunction in mild Parkinson's disease associated with dementia (PDD) are similar to those in mild Alzheimer's disease (AD), it is difficult to accurately differentiate between these two types of dementia in their early phases using neuropsychological tests. The purpose of the current study was to investigate differences in cerebral perfusion patterns of patients with AD and PDD at the earliest stages using single photon emission computed tomography (SPECT). Methods: We consecutively recruited 31 patients with mild PDD, 32 patients with mild probable AD and 33 age-matched healthy subjects. All subjects underwent ^99mTc-hexamethylpropyleneamine oxime perfusion SPECT and completed general neuropsychological tests. Results: We found that both mild PDD and AD patients showed distinct hypoperfusion in frontal, parietal and temporal regions, compared with healthy subjects. More importantly, hypoperfusion in occipital and cerebellar regions was observed only in mild PDD. Conclusion: The observation of a significant decrease in cerebral perfusion in occipital and cerebellar regions in patients with mild PDD is likely useful to differentiate between PDD and AD at the earliest stages.

A Comparison of Substantia Nigra T1 Hyperintensity in Parkinson's Disease Dementia, Alzheimer's Disease and Age-Matched Controls: Volumetric Analysis of Neuromelanin Imaging

“…Obtaining a differential diagnosis of PDD and AD is sometimes difficult based on symptoms and clinical tests alone (11). Hence, more objective tests, such as the T1 hyperintensity volume measures, may be helpful in early diagnosis of PDD vs.…”

“…PD-related dementia (PDD) is characterized by executive dysfunction, disordered attention, and decreased visuospatial/constructional abilities (10). As 26% of patients with PDD present with cognitive symptoms that overlap those observed in patients with Alzheimer's disease (AD), a differential diagnosis between PDD and AD is sometimes difficult especially in the early stages and particularly when using neuropsychiatric tests alone (1011). Despite overlapping cognitive symptoms, the major pathology of PDD is loss of the neuromelanin-containing dopaminergic neurons of SN, while that of AD is not, although there is a debate on the role of dopamine in AD pathology (12).…”

Biomarkers for dementia and mild cognitive impairment in Parkinson's disease

“…2). In several studies, PDD and PD-MCI patients exhibit areas of reduced rCBF [234][235][236][237][238][239][240][241][242][243][244][245][246][247][248][249] and metabolism (more extensive in PDD), 212,[250][251][252][253][254][255][256][257][258] such as in the frontal, parietal, temporal, occipital and cingulate cortex, the basal ganglia, thalamus, and cerebellum. Interestingly, when compared with PD-MCI patients, hypometabolism is more widespread in PDD patients, especially in the posterior cortical areas, 251 and this heralds the progression to dementia in PD patients when considered in conjunction with the hypometabolism in the posterior cingulate and caudate nucleus.…”

Wavelet Energy and Wavelet Coherence as EEG Biomarkers for the Diagnosis of Parkinson’s Disease-Related Dementia and Alzheimer’s Disease

“…at resolution level j and sampled time k. As a consequence, the wavelet coherence could be obtained from each frequency bands F 1 (50- 6 bands, which are relevant to the θ and δ frequency bands, were also excluded because low frequency EEG components are highly influenced by volume conduction effects [31,32]. To investigate volume conduction effects, distance-dependent differences in coherence were examined using the WC values of the control groups.…”