Clinical‐neuroimaging characteristics of dysexecutive mild cognitive impairment

Pa, Judy; Boxer, Adam L.; Chao, Li-Lian; Gazzaley, Adam; Freeman, Katie M.; Kramer, Joel H.; Miller, Bruce L.; Weiner, Michael W.; Neuhaus, John; Johnson, Julene K.

doi:10.1002/ana.21591

Cited by 89 publications

(103 citation statements)

References 44 publications

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“…Thus, the literature suggests that individuals with MCI have WM deficits that are evident irrespective of the sensory modality of the information and the MCI subtype. The underlying mechanisms for these deficits remain uncertain, but pathological changes in the brain regions that subserve WM, such as frontal lobe atrophy [20,21] and dysfunction [22,23], likely contribute to these deficits.…”

Section: Introductionmentioning

confidence: 99%

Reduced Frontal Activations at High Working Memory Load in Mild Cognitive Impairment: Near-Infrared Spectroscopy

Yeung¹,

Sze²,

Woo

et al. 2016

Dement Geriatr Cogn Disord

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Background: Some functional magnetic resonance imaging studies have reported altered activations in the frontal cortex during working memory (WM) performance in individuals with mild cognitive impairment (MCI), but the findings have been mixed. The objective of the present study was to utilize near-infrared spectroscopy (NIRS), an alternative imaging technique, to examine neural processing during WM performance in individuals with MCI. Methods: Twenty-six older adults with MCI (7 males; mean age 69.15 years) were compared with 26 age-, gender-, handedness-, and education-matched older adults with normal cognition (NC; 7 males; mean age 68.87 years). All of the participants undertook an n-back task with a low (i.e., 0-back) and a high (i.e., 2-back) WM load condition while their prefrontal dynamics were recorded by a 16-channel NIRS system. Results: Although behavioral results showed that the two groups had comparable task performance, neuroimaging results showed that the MCI group, unlike the NC group, did not exhibit significantly increased frontal activations bilaterally when WM load increased. Compared to the NC group, the MCI group had similar frontal activations at low load (p > 0.05 on all channels) but reduced activations at high load (p < 0.05 on 4 channels), thus failing to demonstrate WM-related frontal activations (p < 0.05 on 9 channels). In addition, we found a positive correlation between the left WM-related frontal activations and WM ability primarily in the NC group (r_s = 0.42, p = 0.035), suggesting a relationship between frontal hypoactivation and WM difficulties. Conclusion: The present findings suggest the presence of frontal dysfunction that is dependent on WM load in individuals with MCI.

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Section: Introductionmentioning

confidence: 99%

Reduced Frontal Activations at High Working Memory Load in Mild Cognitive Impairment: Near-Infrared Spectroscopy

Yeung¹,

Sze²,

Woo

et al. 2016

Dement Geriatr Cogn Disord

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“…A recent amyloid imaging study with Pittsburgh compound B revealed no differences between aMCI and naMCI [12]. In MRI studies, mesial, inferior temporal, right inferior parietal and posterior cingulate cortex atrophy were more pronounced in aMCI than naMCI [13,14,15,16]. White matter loss in periventricular areas as well as in the frontal, parietal, temporal and posterior cingulate cortex and the splenium of corpus callosum were also more common in aMCI [17,18,19,20].…”

Section: Introductionmentioning

confidence: 99%

“…Nonamnestic MCI cases displayed less severe gray matter and white matter loss in the mesial temporal lobe [14,16,21], diffuse white matter changes in other cortical areas [18] and a greater proportion of cortical infarcts compared to aMCI [13]. In contrast to aMCI cases that display mesial temporal lobe, inferior parietal and posterior cingulate cortex atrophy, dysexecutive MCI cases have more pronounced left frontal lobe damage [22]. …”

Section: Introductionmentioning

confidence: 99%

Attention-Related Potentials Allow for a Highly Accurate Discrimination of Mild Cognitive Impairment Subtypes

Missonnier

Herrmann²,

Richiardi³

et al. 2012

Neurodegener Dis

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The three most frequent forms of mild cognitive impairment (MCI) are single-domain amnestic MCI (sd-aMCI), single-domain dysexecutive MCI (sd-dMCI) and multiple-domain amnestic MCI (md-aMCI). Brain imaging differences among single domain subgroups of MCI were recently reported supporting the idea that electroencephalography (EEG) functional hallmarks can be used to differentiate these subgroups. We performed event-related potential (ERP) measures and independent component analysis in 18 sd-aMCI, 13 sd-dMCI and 35 md-aMCI cases during the successful performance of the Attentional Network Test. Sensitivity and specificity analyses of ERP for the discrimination of MCI subgroups were also made. In center-cue and spatial-cue warning stimuli, contingent negative variation (CNV) was elicited in all MCI subgroups. Two independent components (ICA1 and 2) were superimposed in the time range on the CNV. The ICA2 was strongly reduced in sd-dMCI compared to sd-aMCI and md-aMCI (4.3 vs. 7.5% and 10.9% of the CNV component). The parietal P300 ERP latency increased significantly in sd-dMCI compared to md-aMCI and sd-aMCI for both congruent and incongruent conditions. This latency for incongruent targets allowed for a highly accurate separation of sd-dMCI from both sd-aMCI and md-aMCI with correct classification rates of 90 and 81%, respectively. This EEG parameter alone performed much better than neuropsychological testing in distinguishing sd-dMCI from md-aMCI. Our data reveal qualitative changes in the composition of the neural generators of CNV in sd-dMCI. In addition, they document an increased latency of the executive P300 component that may represent a highly accurate hallmark for the discrimination of this MCI subgroup in routine clinical settings.

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“…It is likely that the different non-amnestic single-domain MCI subgroups (e.g. dysexecutive, language, visuospatial) will have distinct clinical features and different risks for converting to dementia [7,8] . It is, therefore, important to subdivide single-domain non-amnestic MCI groups to improve clinical differentiation.…”

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confidence: 99%

Baseline Predictors of Clinical Progression among Patients with Dysexecutive Mild Cognitive Impairment

Johnson¹,

Boxer

et al. 2010

Dement Geriatr Cogn Disord

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Background/Aims: There are few studies that evaluate the clinical outcomes of individuals with non-amnestic mild cognitive impairment (MCI). The purpose of this study was to evaluate baseline predictors of clinical progression after 2 years for patients with dysexecutive MCI (dMCI), a single-domain non-amnestic MCI subgroup. Methods:We evaluated clinical progression in a sample of 31 older adults with dMCI. Clinical progression was defined as a worsening on the Clinical Dementia Rating sum of boxes at the 2-year visit, whereas patients were classified as stable if the score did not worsen over 2 years. We compared baseline brain MRI, neuropsychological tests, and health risk factors. Results: Twelve individuals with dMCI progressed clinically, and 19 individuals remained stable over 2 years. Compared to the stable dMCI patients, the dMCI patients who progressed showed brain atrophy in the bilateral insula and left lateral temporal lobe on MRI. dMCI patients who progressed were also older, had lower baseline performance on category fluency and a spatial location task, and reported fewer dysexecutive symptoms. Health risk factors, except hypertension, did not differ between groups. Conclusion: The results suggest that dMCI patients who progress relatively quickly over 2 years may have unique clinical and brain MRI features.

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Clinical‐neuroimaging characteristics of dysexecutive mild cognitive impairment

Cited by 89 publications

References 44 publications

Reduced Frontal Activations at High Working Memory Load in Mild Cognitive Impairment: Near-Infrared Spectroscopy

Reduced Frontal Activations at High Working Memory Load in Mild Cognitive Impairment: Near-Infrared Spectroscopy

Attention-Related Potentials Allow for a Highly Accurate Discrimination of Mild Cognitive Impairment Subtypes

Baseline Predictors of Clinical Progression among Patients with Dysexecutive Mild Cognitive Impairment

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