The Profile of Executive Functioning in Amnestic Mild Cognitive Impairment: Disproportionate Deficits in Inhibitory Control

Abstract

Amnestic mild cognitive impairment (aMCI) represents a group of individuals who are highly likely to develop Alzheimer's disease (AD). Although aMCI is typically conceptualized as involving predominantly deficits in episodic memory, recent studies have demonstrated that deficits in executive functioning may also be present, and thorough categorization of cognitive functioning in MCI may improve early diagnosis and treatment of AD. We first provide an extensive review of neuropsychology studies that examined executive functioning in MCI. We then present data on executive functioning across multiple sub-domains (divided attention, working memory, inhibitory control, verbal fluency, and planning) in 40 aMCI patients (single or multiple domain) and 32 normal elderly controls (NECs). MCI patients performed significantly worse than NECs in all 5 sub-domains, and there was impairment (>1.0 SD below the mean of NECs) in all sub-domains. Impairment on each test was frequent, with 100% of MCI patients exhibiting a deficit in at least one sub-domain of executive functioning. Inhibitory control was the most frequently and severely impaired. These results indicate that executive dysfunction in multiple sub-domains is common in aMCI and highlights the importance of a comprehensive neuropsychological evaluation for fully characterizing the nature and extent of cognitive deficits in MCI.

Alpha-Band Hypersynchronization in Progressive Mild Cognitive Impairment: A Magnetoencephalography Study

“…Peters et al (2014) found that one of the best predictors of the conversion from MCI to AD after 2 years was the cortical thinning in the right anterior cingulate. Johnson et al (2007) reported an more increased perfusion in pMCI patients than in sMCI patients within a 5 year follow-up period in the rostral anterior cingulate. Recently, Okello et al (2009) found that faster converters (average of 1 year, as our patients) showed a higher amyloid deposition in the anterior cingulate than slow converters.…”

“…Jelic et al (2000) reported that the best predictor of future conversion from MCI to AD was an increased theta power and a decrease in alpha activity, whereas Huang et al (2000) evidenced that the best predictor was the shift of alpha activity toward anterior brain. found that pMCI patients exhibit higher power values in the delta, theta, and alpha 1 bands, mainly over temporal and parietal areas, and also changes in frontoparietal midline coherence values.…”

“…Hippocampal, parahippocampal, and entorhinal volumes were measured as anatomical evidences of brain atrophy characteristic for MCI and AD (Albert et al, 2011;McKhann et al, 2011). In addition, these measures have shown previously its predictive power in AD progression (Jack et al, 1999;deToledo-Morrell et al, 2004;Devanand et al, 2007). For most of the subjects included in this paper (23 sMCI and 14 pMCI), a T1-weighted MRI was available, acquired in a GE Healthcare 1.5 Tesla magnetic resonance scanner, using a high-resolution antenna and a homogenization pure filter (fast spoiled gradient echo sequence; repetition time, 11.2 ms; echo time, 4.2 ms; inversion time, 450 ms; flip angle, 12°; 1 mm slice thickness; 256 ϫ 256 matrix; and field of view, 25 cm).…”

“…Magnetic resonance imaging (MRI) studies have observed a hippocampal and entorhinal cortex atrophy in MCI patients progressing to AD [progressive MCI (pMCI); (deToledo-Morrell et al, 2004;Devanand et al, 2007]. Meanwhile, fluoro-deoxyglucose positron emission tomography (PET) studies have shown that pMCI patients present regional hypometabolism in the temporal, parietal, and/or precuneus cortices compared with MCI patients that remain stable [stable MCI (sMCI;Hatashita and Yamasaki, 2013]. Most of the Pittsburgh compound B (PIB)-PET studies show that PIB-positive MCI patients are significantly more likely to convert to AD than PIBnegative patients (Grimmer et al, 2013).…”

O2‐07‐03: Patterns of Cognitive Decline Prior to Dementia in Persons With Mild Cognitive Impairment

“…So perhaps, not all of these domains are equally sensitive to AD [42]. Among them, inhibition and working memory appeared to be particularly sensitive and were reported to be severely impaired in MCI [43][44][45][46]. One other crucial difference between the two studies is that we differentiated nonprogressor from progressor MCI.…”