Article abstract—Objective: To update the 1994 practice parameter for the diagnosis of dementia in the elderly. Background: The AAN previously published a practice parameter on dementia in 1994. New research and clinical developments warrant an update of some aspects of diagnosis. Methods: Studies published in English from 1985 through 1999 were identified that addressed four questions: 1) Are the current criteria for the diagnosis of dementia reliable? 2) Are the current diagnostic criteria able to establish a diagnosis for the prevalent dementias in the elderly? 3) Do laboratory tests improve the accuracy of the clinical diagnosis of dementing illness? 4) What comorbidities should be evaluated in elderly patients undergoing an initial assessment for dementia? Recommendations: Based on evidence in the literature, the following recommendations are made. 1) The DSM-III-R definition of dementia is reliable and should be used (Guideline). 2) The National Institute of Neurologic, Communicative Disorders and Stroke‐AD and Related Disorders Association (NINCDS-ADRDA) or the Diagnostic and Statistical Manual, 3rd edition, revised (DSM-IIIR) diagnostic criteria for AD and clinical criteria for Creutzfeldt‐Jakob disease (CJD) have sufficient reliability and validity and should be used (Guideline). Diagnostic criteria for vascular dementia, dementia with Lewy bodies, and frontotemporal dementia may be of use in clinical practice (Option) but have imperfect reliability and validity. 3) Structural neuroimaging with either a noncontrast CT or MR scan in the initial evaluation of patients with dementia is appropriate. Because of insufficient data on validity, no other imaging procedure is recommended (Guideline). There are currently no genetic markers recommended for routine diagnostic purposes (Guideline). The CSF 14-3-3 protein is useful for confirming or rejecting the diagnosis of CJD (Guideline). 4) Screening for depression, B12 deficiency, and hypothyroidism should be performed (Guideline). Screening for syphilis in patients with dementia is not justified unless clinical suspicion for neurosyphilis is present (Guideline). Conclusions: Diagnostic criteria for dementia have improved since the 1994 practice parameter. Further research is needed to improve clinical definitions of dementia and its subtypes, as well as to determine the utility of various instruments of neuroimaging, biomarkers, and genetic testing in increasing diagnostic accuracy.

https://n.neurology.org/content/neurology/56/9/1143.full.pdf

Practice parameter: Diagnosis of dementia (an evidence-based review) Report of the Quality Standards Subcommittee of the American Academy of Neurology

Brain activation in PTSD in response to trauma-related stimuli.

A high percentage of patients with mild cognitive impairment (MCI) develop clinical dementia of the Alzheimer type (AD) within 1 year. The aim of this longitudinal study was to identify characteristic patterns of cerebral metabolism at baseline in patients converting from MCI to AD, and to evaluate the changes in these patterns over time. Baseline and follow-up examinations after 1 year were performed in 22 MCI patients (12 males, 10 females, aged 69.8±5.8 years); these examinations included neuropsychological testing, structural cranial magnetic resonance imaging and fluorine-18 fluorodeoxyglucose positron emission tomography (PET) evaluation of relative cerebral glucose metabolic rate (rCMRglc). Individual PET scans were stereotactically normalised with NEUROSTAT software (Univ. of Michigan, Ann Arbor, USA). Subsequently, statistical comparison of PET data with an age-matched healthy control population and between patient subgroups was performed using SPM 99 (Wellcome Dept. of Neuroimaging Sciences, London, UK). After 1 year, eight patients (36%) had developed probable AD (referred to as MCIAD), whereas 12 (55%) were still classified as having stable MCI (referred to as MCIMCI). Compared with the healthy control group, a reduced rCMRglc in AD-typical regions, including the temporoparietal and posterior cingulate cortex, was detected at baseline in patients with MCIAD. Abnormalities in the posterior cingulate cortex reached significance even in comparison with the MCIMCI group. After 1 year, MCIAD patients demonstrated an additional bilateral reduction of rCMRglc in prefrontal areas, along with a further progression of the abnormalities in the parietal and posterior cingulate cortex. No such changes were observed in the MCIMCI group. In patients with MCI, characteristic cerebral metabolic differences can be delineated at the time of initial presentation, which helps to define prognostic subgroups. A newly emerging reduction of rCMRglc in prefrontal cortical areas is associated with the transition from MCI to AD.

Cerebral metabolic changes accompanying conversion of mild cognitive impairment into Alzheimer's disease: a PET follow-up study.

To evaluate the utility of arterial spin-labeled blood flow magnetic resonance imaging for the detection of cerebral blood flow abnormalities in Alzheimer's disease, arterial spin-labeled blood flow images in 16 contiguous 5-mm axial sections were acquired in 18 patients diagnosed with probable Alzheimer's disease and 11 age-matched controls. Blood flow images from all subjects were transformed to a standard anatomical space for voxel-by-voxel statistical analysis. High quality blood flow images were obtained from all but 1 subject. Statistical analysis demonstrated significant flow decreases relative to control subjects in temporal, parietal, frontal, and posterior cingulate cortices. Increased severity of disease, as measured by Mini-Mental State Examination, correlated with posterior parietal and posterior cingulate decreases but not temporal decreases. Arterial spin-labeled magnetic resonance imaging was found to be an effective tool for characterizing flow decreases accompanying Alzheimer's disease. The absence of ionizing radiation or injection and the ability to obtain high quality anatomical images within the same scanning session make arterial spin labeling an attractive technique for the study of Alzheimer's disease, for the evaluation of pharmacological therapies, and, possibly, for early diagnosis.

Assessment of cerebral blood flow in Alzheimer's disease by spin-labeled magnetic resonance imaging.

Astrocytes colocalize with fibrillar amyloid-beta (A beta) plaques in postmortem Alzheimer disease (AD) brain tissue. It is therefore of great interest to develop a PET tracer for visualizing astro ...

https://jnm.snmjournals.org/content/jnumed/53/1/37.full.pdf

Evidence for Astrocytosis in Prodromal Alzheimer Disease Provided by 11C-Deuterium-L-Deprenyl: A Multitracer PET Paradigm Combining 11C-Pittsburgh Compound B and 18F-FDG

This study evaluated an automated analysis of SPECT brain imaging in patients with Alzheimer9s disease (AD). Methods: Patients [n =81; mean age, 69.9 ± 10.6 yr (mean ± s.d.)] with a clinical diagnosis of probable AD (NINCDS-Alzheimer9s Disease and Related Disorders Association criteria) underwent 99mTc-ethyl cysteine dimer SPECT imaging. After imaging registration and data extraction using three-dimensional stereotactic surface projections, a pixel-wise comparison of ethyl cysteine dimer uptake was performed using a reference database of 10 cognitive intact controls of comparable age. Results: When individual cases were compared to the normal database, tempora-parietal regional cerebral blood flow (rCBF) abnormalities across different levels of dementia severity were clearly depicted on pixel-wise Z-score images. The rCBF reduction incortical association areas showed a significant correlation with an overall level of cognitive decline, as assessed by the Mini Mental State Examination and by the cognitive section of the Cambridge Mental Disorders of the Elderly Examination. In addition, there were significant region-specific correlations between left temporo perfusion deficit and language performance and between right parietal rCBF reduction and praxis. Conclusion: These results indicate that this observer-independent analysis of SPECT data enables objective and semiquantitative assessment of the magnitude and extentof cortical perfusion abnormalities in patients with AD.

https://jnm.snmjournals.org/content/jnumed/38/7/1095.full.pdf

Quantitative Assessment of Cerebral Blood Flow in Patients with Alzheimer's Disease by SPECT

The aim of the study was to evaluate an observer-independent semiquantitative analysis of brain imaging by single-photon emission computed tomography (SPECT) in patients with Alzheimer''s disease (AD)

Reduction of regional cerebral blood flow and cognitive impairment in patients with Alzheimer's disease: evaluation of an observer-independent analytic approach.

Dagmar Mösch

Papers

Quantitative Assessment of Cerebral Blood Flow in Patients with Alzheimer's Disease by SPECT

Reduction of regional cerebral blood flow and cognitive impairment in patients with Alzheimer's disease: evaluation of an observer-independent analytic approach.