Susan E. McPherson

Synchronous neural interactions assessed by magnetoencephalography: a functional biomarker for brain disorders

We report on a test to assess the dynamic brain function at high temporal resolution using magnetoencephalography (MEG). The essence of the test is the measurement of the dynamic synchronous neural interactions, an essential aspect of the brain function. MEG signals were recorded from 248 axial gradiometers while 142 human subjects fixated a spot of light for 45-60 s. After fitting an autoregressive integrative moving average (ARIMA) model and taking the stationary residuals, all pairwise, zero-lag, partial cross-correlations (PCC(ij)(0)) and their z-transforms (z(ij)(0)) between i and j sensors were calculated, providing estimates of the strength and sign (positive, negative) of direct synchronous coupling at 1 ms temporal resolution. We found that subsets of z(ij)(0) successfully classified individual subjects to their respective groups (multiple sclerosis, Alzheimers disease, schizophrenia, Sjögrens syndrome, chronic alcoholism, facial pain, healthy controls) and gave excellent external cross-validation results.

Screening for Cognitive Impairment in an Elderly Veteran Population: Acceptability and Results Using Different Versions of the Mini-Cog

OBJECTIVES: To assess the feasibility of cognitive screening in older veterans presenting for routine primary care.

Noninvasive quantification of ascorbate and glutathione concentration in the elderly human brain

In this study, ascorbate (Asc) and glutathione (GSH) concentrations were quantified noninvasively using double‐edited 1H MRS at 4 T in the occipital cortex of healthy young [age (mean ± standard deviation) = 20.4 ± 1.4 years] and elderly (age = 76.6 ± 6.1 years) human subjects. Elderly subjects had a lower GSH concentration than younger subjects (p < 0.05). The Asc concentration was not significantly associated with age. Furthermore, the lactate (Lac) concentration was higher in elderly than young subjects. Lower GSH and higher Lac concentrations are indications of defective protection against oxidative damage and impaired mitochondrial respiration. The extent to which the observed concentration differences could be associated with physiological differences and methodological artifacts is discussed. In conclusion, GSH and Asc concentrations were compared noninvasively for the first time in young vs elderly subjects. Copyright

Finding Dementia in Primary Care: The Results of a Clinical Demonstration Project

To assess the effect of screening on diagnosing cognitive impairment.

Fluorodeoxyglucose positron emission tomography of mild cognitive impairment with clinical follow-up at 3 years

Alzheimers disease (AD) is the most common dementing illness. Development of effective treatments directed at AD requires an early diagnosis. Mild cognitive impairment (MCI) often heralds AD. Thus, characterizing MCI is fundamental to the early diagnosis of AD.

Canonical correlation analysis of synchronous neural interactions and cognitive deficits in Alzheimer's dementia

In previous work (Georgopoulos et al 2007 J. Neural Eng. 4 349-55) we reported on the use of magnetoencephalographic (MEG) synchronous neural interactions (SNI) as a functional biomarker in Alzheimers dementia (AD) diagnosis. Here we report on the application of canonical correlation analysis to investigate the relations between SNI and cognitive neuropsychological (NP) domains in AD patients. First, we performed individual correlations between each SNI and each NP, which provided an initial link between SNI and specific cognitive tests. Next, we performed factor analysis on each set, followed by a canonical correlation analysis between the derived SNI and NP factors. This last analysis optimally associated the entire MEG signal with cognitive function. The results revealed that SNI as a whole were mostly associated with memory and language, and, slightly less, executive function, processing speed and visuospatial abilities, thus differentiating functions subserved by the frontoparietal and the temporal cortices. These findings provide a direct interpretation of the information carried by the SNI and set the basis for identifying specific neural disease phenotypes according to cognitive deficits.

Normative data for healthy older adults and an abbreviated version of the Stroop test

Normative data for the Kaplan version of the Stroop Test are presented for 153 healthy, cognitively intact older adults aged 50–89 years. Increasing age was associated with decreased performance on all three subtests (Stroop A, Stroop B, and Stroop C), while years of education was only associated with Stroop B performance. Hence the normative data were stratified by age into three groups (50–64, 65–74, 75–89). Completion times for the first half of each trial (half-time scores) were found to have good split-half reliability and correlated highly with the original full administration scores. Means and standard deviations for the half-time administration are also presented for this sample. The current study provides more comprehensive normative data for older adults than previously available, as well as normative information for half-time scores that may have future clinical utility as an alternative, abbreviated version of the Kaplan Stroop Test.

Screening for Cognitive Impairment in an Elderly Veteran Population: Acceptability and Results Using Different Versions of the Mini-Cog: SCREENING ELDERLY VETERANS USING THE MINI-COG

OBJECTIVES: To assess the feasibility of cognitive screening in older veterans presenting for routine primary care.

Screening for cognitive impairment in an elderly veteran population

OBJECTIVES: To assess the feasibility of cognitive screening in older veterans presenting for routine primary care.

P2-222: Classification of normal elderly, MCI, and mild AD using neuropsychological tests and self-reported memory function

total tau, and p-tau 181 levels in CSF. Objective: To investigate predictors of a 1-year outcome. Subjects: Inclusion criteria were age 55 years and a new referral to a memory clinic. Exclusion criteria were dementia and disorders causing cognitive impairment. For the present analysis we selected all subjects with data on the 1-year follow-up (n 298). Subjects were at baseline on average 71 years old, scored 27.5 on the MMSE, and had 9.5 years of education. 59% of the subjects were female. Data on the APOE genotype, medial temporal lobe atrophy, and CSF values were collected in a subgroup only. Outcome measures were AD and cognitive decline at follow-up. Cognitive decline was defined as AD at follow-up, decline of at least 1 standard deviation on a memory test, or persisting memory impairment. Results: Predictors of AD were score on the delayed recall of a word list (t 2.6, p 0.01), verbal fluency (t 2.5, p 0.01), MMSE score (t 3.3, p 0.003), total tau (t 4.0, p 0.003), and p-tau 181 (t 2.5, p 0.02). Predictors of cognitive decline were age (t 4.0, p 0.001), score on the delayed recall of a word list (t 10, p 0.001), verbal fluency (t 7.9, p 0.001), score on the TMT B (t 3.1, p 0.002), MMSE score (t 5.2, p 0.001), functional impairment (chi-square 9.2, p 0.01), medial temporal lobe atrophy (chi-square 23, p 0.001), total tau (t 2.3, p 0.04), and the APOE-e4 allele (chi-square 4.4, p 0.04). Conclusions: Subjects who rapidly decline to AD are characterized by low cognitive scores and high CSF tau levels at baseline. Other predictors of AD such as age, functional impairment, medial temporal lobe atrophy, and the APOE-e4 allele may predict AD only at longer follow-up intervals. Acknowledgement: The study was funded by the European Commission (QLRT-2001-2455).