Total Mini-Mental State Examination score and regional cerebral blood flow using Z score imaging and automated ROI analysis software in subjects with memory impairment

Oscillatory characteristics of resting-state magnetoencephalography reflect pathological and symptomatic conditions of cognitive impairment

Background

Dementia and mild cognitive impairment are characterised by symptoms of cognitive decline, which are typically assessed using neuropsychological assessments (NPAs), such as the Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB). Magnetoencephalography (MEG) is a novel clinical assessment technique that measures brain activities (summarised as oscillatory parameters), which are associated with symptoms of cognitive impairment. However, the relevance of MEG and regional cerebral blood flow (rCBF) data obtained using single-photon emission computed tomography (SPECT) has not been examined using clinical datasets. Therefore, this study aimed to investigate the relationships among MEG oscillatory parameters, clinically validated biomarkers computed from rCBF, and NPAs using outpatient data retrieved from hospital records.

Methods

Clinical data from 64 individuals with mixed pathological backgrounds were retrieved and analysed. MEG oscillatory parameters, including relative power (RP) from delta to high gamma bands, mean frequency, individual alpha frequency, and Shannon's spectral entropy, were computed for each cortical region. For SPECT data, three pathological parameters-'severity', 'extent', and 'ratio'-were computed using an easy z-score imaging system (eZIS). As for NPAs, the MMSE and FAB scores were retrieved.

Results

MEG oscillatory parameters were correlated with eZIS parameters. The eZIS parameters associated with Alzheimer's disease pathology were reflected in theta power augmentation and slower shift of the alpha peak. Moreover, MEG oscillatory parameters were found to reflect NPAs. Global slowing and loss of diversity in neural oscillatory components correlated with MMSE and FAB scores, whereas the associations between eZIS parameters and NPAs were sparse.

Conclusion

MEG oscillatory parameters correlated with both SPECT (i.e. eZIS) parameters and NPAs, supporting the clinical validity of MEG oscillatory parameters as pathological and symptomatic indicators. The findings indicate that various components of MEG oscillatory characteristics can provide valuable pathological and symptomatic information, making MEG data a rich resource for clinical examinations of patients with cognitive impairments. SPECT (i.e. eZIS) parameters showed no correlations with NPAs. The results contributed to a better understanding of the characteristics of electrophysiological and pathological examinations for patients with cognitive impairments, which will help to facilitate their co-use in clinical application, thereby improving patient care.

Cerebral perfusion and the risk of cognitive decline and dementia in community dwelling older people

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Cerebral blood flow (CBF) and spatial coefficient of variation of the arterial transit time (ATT) are less sensitive markers of cognitive impairment and clinical dementia.

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Greater white matter hyperintensity volume (WMHV) was consistently associated with cognitive impairment and dementia, rendering it as a more sensitive longitudinal marker.

Background

The arterial spin labeling-spatial coefficient of variation (sCoV) is a new vascular magnetic resonance imaging (MRI) parameter that could be a more sensitive marker for dementia-associated cerebral microvascular disease than the commonly used MRI markers cerebral blood flow (CBF) and white matter hyperintensity volume (WMHV).

Methods

195 community-dwelling older people with hypertension were invited to undergo MRI twice, with a three-year interval. Cognition was evaluated every two years for 6-8 years using the mini-mental state examination (MMSE). We assessed relations of sCoV, CBF and WMHV with cognitive decline during follow-up. We also registered dementia diagnoses, up to 9 years after the first scan. In an additional analysis, we compared these MRI parameters between participants that did and did not develop dementia.

Results

136/195 completed the second scan. sCoV and CBF were not associated with MMSE changes during 6-8 years of follow-up. Higher WMHV was associated with declining MMSE scores (-0.02 points/year/ml, 95%CI=-0.03 to -0.00). ScOv and CBF did not differ between participants who did (n=15) and did not (n=180) develop dementia, whereas higher WMHV was reported in participants who developed dementia after the first MRI (13.3 vs 6.1mL, p<0.001). There were no associations between longitudinal change in any of the MRI parameters and cognitive decline or subsequent dementia.

Conclusion

Global sCoV and CBF were less sensitive longitudinal markers of cognitive decline and dementia compared to WMHV in community-dwelling older people with hypertension. Larger longitudinal MRI perfusion studies are needed to identify possible (regional) patterns of cerebral perfusion preceding cognitive decline and dementia diagnosis.

Carotid Revascularization Improves Cognition in Patients With Asymptomatic Carotid Artery Stenosis and Cognitive Decline. Greater Improvement in Younger Patients With More Disordered Neuropsychological Performance

OBJECTIVES

There has been a growing interest in whether carotid revascularization may reverse cognitive decline. In this study the aim was to assess cognitive changes after carotid artery endarterectomy and stenting, using neuropsychological assessment with MoCA and CANTAB test.

MATERIALS AND METHODS

Seventy patients with asymptomatic carotid artery stenosis, qualified for CEA (study group A) and CAS (study group B) have been prospectively assessed. 20 patients with lower extremity artery disease (control group C) and 15 patients qualified for inguinal hernia surgery (control group D) have served as a control group. Patients have been evaluated 1 day before surgery and 6 months after, using MoCA and CANTAB test. Logistic regression models were built to determine variables affecting cognitive performance.

RESULTS

After the procedure in the study group A the cognitive evaluation showed improvement in 5 cognitive domains tested in MoCA: visuospatial/executive (p=.0496), naming (p=.0831), language (p=.0009), abstraction (p=.0126) and delayed recall (p=.0016). In CANTAB there were improvement in PAL (p=.0290) and SWM (p=.0105). In study group B positive cognitive changes were seen in visuospatial/executive (p=.0827) and delayed recall (p=.0041) tested with MoCA and in PAL (PALFAMS28 p=.0315, PALNPR28 p=.0090, PALTEA28 p=.0058) and SWM (p=.0882) tested with CANTAB. Using a regression model, the only strong predictors of cognitive improvement on the follow-up visit were younger age and lower MoCA score on the first visit.

CONCLUSIONS

Carotid revascularization, both open and endovascular, lead to cognitive improvement in patients with severe carotid stenosis and cognitive decline. This effect seems to be stronger in younger patients with worst cognitive performance before surgery.

Association between Regional Cerebral Blood Flow and Mini-Mental State Examination Score in Patients with Alzheimer's Disease

BACKGROUND

In patients with Alzheimer's disease (AD), cerebral blood flow (CBF) is decreased from the early stages. CBF in AD is currently estimated from Z-scores using statistical analysis. However, the Z-score is not considered the impaired area ratio.

METHODS

In the present study, a novel indicator, ΣzS, associated with brain surface area and Zscores, is defined and the association with regional CBF has been estimated using Mini-Mental State Examination (MMSE) scores, which indicate the severity of cognitive impairment in patients with AD.

RESULTS

A negative correlation was detected between ΣzS in the posterior cingulate gyrus and the subset numbers 1, 2, and 5 of the total MMSE scores. Furthermore, a negative correlation was detected between the total MMSE score and ΣzS in Brodmann area 30, which is a subdivided area of the brain.

CONCLUSION

These results suggest that ΣzS may be a useful indicator of CBF metabolism, and thus may improve the current understanding of cognitive function in patients with AD.

Cerebral blood flow in young and middle-aged people living with HIV

Purpose: Neurocognitive disorder has been noted as a long-term complication in individuals with HIV. In people living with HIV, regardless of treatment, age-related changes like arteriosclerosis are well-known to be accelerated. Such accelerated aging changes may decrease cerebral blood flow in younger generations with HIV, increasing the rate of occurrence of neurocognitive disorders. We investigated regional cerebral blood flows in well-controlled Japanese people living with HIV under 65 years old to clarify whether age-related changes in regional cerebral blood flows are accelerated in people living with HIV.Method: Japanese male HIV patients >20 years old but <65 years old who visited Teikyo University Hospital between August 2013 and September 2015 were recruited to and enrolled in this study. Healthy coeval male volunteers during the same period were recruited as controls. Magnetic resonance imaging was performed. Twelve regional cerebral blood flows were calculated from pseudocontinuous arterial spine labelling data.Results: Participants in this study comprised 40 individuals with HIV (HIV-positive group) and 33 non-HIV individuals (Control group). Median age was 40.15 years [interquartile range (IQR), 32.80-50.55 years] for the HIV-positive group and 48.00 years [IQR, 37.75-59.25 years; p = 0.3585] for the Control group. No significant differences in regional cerebral blood flows were seen between groups. In the HIV-positive group, cerebral blood flows decreased with age in the neocortex, although no significant decrease was observed in any of the regions in the control group.Conclusions: Significant age-related declines in cerebral blood flows in the neocortex may occur earlier in HIV patients.

Correlation of cognition and SPECT perfusion: easy Z score and SPM analysis of a pilot sample with cerebral small vessel disease

BACKGROUND/AIMS

To associate neuropsychology test performance with perfusion on single-photon emission computed tomography (SPECT) among 12 patients with cerebral small vessel disease.

METHODS

The easy Z score imaging system (eZIS) was used to compare patient images to those of normal controls. Scores from neuropsychological tests commonly used to screen for dementia were associated with SPECT resting perfusion image values using the statistical parametric mapping (SPM) program.

RESULTS

Immediate Memory and Delayed Memory index scores, as well as memory subtests of the Repeatable Battery for Assessment of Neuropsychological Status showed cluster- and voxelwise positive correlations with hypoperfusion in frontal, temporal and cerebellar regions. Negative correlations, primarily in frontal regions, were interpreted as compensatory hyperperfusion.

CONCLUSION

eZIS and SPM analyses of SPECT images showed perfusion correlations with neuropsychological tests with small vessel disease.

Trail making test part a and brain perfusion imaging in mild Alzheimer's disease

BACKGROUND/AIMS

The Trail Making Test (TMT) has long been used to investigate deficits in cognitive processing speed and executive function in humans. However, there are few studies that elucidate the neural substrates of the TMT. The aim of the present study was to identify the regional perfusion patterns of the brain associated with performance on the TMT part A (TMT-A) in patients with Alzheimer's disease (AD).

METHODS

Eighteen AD patients with poor performance on the TMT-A and 36 age- and sex-matched AD patients with good performance were selected. All subjects underwent brain single photon emission computed tomography.

RESULTS

No significant differences between the good and poor performance groups were found with respect to years of education and revised Addenbrooke's Cognitive Examination scores. However, higher z-scores for hypoperfusion in the bilateral superior parietal lobule were observed in the group that scored poorly on the TMT-A compared with the good performance group.

CONCLUSION

Our results suggest that functional activity of the bilateral superior parietal lobules is closely related to performance time on the TMT-A. Thus, the performance time on the TMT-A might be a promising index of dysfunction of the superior parietal area among mild AD patients.

Cerebral small vessel disease: cognition, mood, daily functioning, and imaging findings from a small pilot sample

Cerebral small vessel disease, a leading cause of cognitive decline, is considered a relatively homogeneous disease process, and it can co-occur with Alzheimer's disease. Clinical reports of magnetic resonance imaging (MRI)/computed tomography and single photon emission computed tomography (SPECT) imaging and neuropsychology testing for a small pilot sample of 14 patients are presented to illustrate disease characteristics through findings from structural and functional imaging and cognitive assessment. Participants showed some decreases in executive functioning, attention, processing speed, and memory retrieval, consistent with previous literature. An older subgroup showed lower age-corrected scores at a single time point compared to younger participants. Performance on a computer-administered cognitive measure showed a slight overall decline over a period of 8–28 months. For a case study with mild neuropsychology findings, the MRI report was normal while the SPECT report identified perfusion abnormalities. Future research can test whether advances in imaging analysis allow for identification of cerebral small vessel disease before changes are detected in cognition.

Association of apolipoproteins e4 and c1 with onset age and memory: a study of sporadic Alzheimer disease in Taiwan

OBJECTIVE

To identify clinical manifestations and neuropsychological effects of Alzheimer disease (AD) in apolipoprotein (ApoE) e4 carriers and to investigate the relationships between ApoE HhaI polymorphism and apolipoprotein C1 (APOC1) HpaI polymorphism in Taiwanese patients with AD.

PARTICIPANTS AND METHODS

A total of 127 patients with AD and 191 elderly individuals were screened for ApoE and APOC1 polymorphism. All patients underwent neuropsychological testing, including a Mini-Mental Status Examination (MMSE), Clinical Dementia Rating (CDR), and/or the Visual Association Memory Test (VAMT) with Cognitive Abilities Screening Instrument.

RESULTS

The frequencies of the e4 and A alleles were significantly higher in the AD group. In the patients with AD, the e4 and A allele effects on those with an age-of-onset of 60 to 79 years were stronger than those with an age-of-onset of 80 years or higher. Visual Association Memory Test performance was significantly worse in e4-allele carriers but not in A-allele carriers, in the early AD, particularly in those affected with AD for less than 2 years. Although there was no statistically significant difference in genotypic frequency between patients and controls, the 2 genes were linked. In addition, the presence of the AA genotype concomitant with the e4 allele may be better associated with AD diagnosis than either factor alone.

CONCLUSION

We conclude that the e4 allele affects neuropsychological performance and illness morbidity. Concomitantly, ApoE e4 and APOC1 A alleles have a better association with AD than ApoE e4 alone. In addition, APOC1 may partially contribute to the pathogenesis of AD, but the nature of its relationship with e4 requires further investigation.