Amnesic Mild Cognitive Impairment Research Articles

Evaluation of Mild Cognitive Impairment through Perientorhinal/Hippocampal Imaging and Comprehensive Neuropsychological and Psychophysical Assessment.

Mild cognitive impairment (MCI) is a significant concern as it is a risk factor for AD progression, and early detection is vital in order to delay dementia onset and enable potential therapeutic interventions. Olfactory impairment is recognized as a predictive biomarker in neurodegenerative processes. The aims of this study were to explore the degree of entorhinal cortical atrophy (ERICA) and the severity of MCI symptoms; to analyze magnetic resonance imaging (MRI) results for the entorhinal cortex, parahippocampal gyrus, peri entorhinal cortex, and the cerebellar tentorium; and to perform a comprehensive neuropsychological and psychophysical assessment. The main results highlighted that in our sample-multidomain amnesic MCI patients with hyposmic symptomatology-we found that ERICA scores were associated with the severity of anxiety symptomatology. One possible hypothesis to explain this observation is that anxiety may contribute to neurodegenerative processes by inducing chronic stress and inflammation. Future research should consider the longitudinal development of neuropsychological scores, anxiety disorders, and brain atrophy to determine their potential predictive value for MCI progression. These findings suggest the importance of psychological factors in MCI progression and the utility of neuropsychological assessment alongside neuroimaging techniques for early detection and follow-up in MCI patients.

Effects of Type 2 Diabetes on the Neuropsychological Profile in Mild Cognitive Impairment.

Diabetes is one of the main risk factors for developing mild cognitive impairment (MCI) and Alzheimer's disease. Most studies have demonstrated a worse performance in executive function, verbal fluency, and information processing speed in patients with diabetes. To assess the cognitive functioning of persons with type 2 diabetes and amnesic mild cognitive impairment (aMCI-T2DM) compared to persons with aMCI without diabetes and persons without diabetes or aMCI as controls, to understand the role of diabetes in the neuropsychological profile. Cross-sectional study involving a sample of 83 patients, ranging in age from 61 to 85 years and divided into three groups: aMCI-T2DM (27 patients), aMCI (29 patients), Controls (27 individuals). All the participants undertook an exhaustive neuropsychological assessment (auditory-verbal and visual memory, attention, information processing speed, language, executive function, and depression). Both groups of aMCI patients performed significantly worse than the controls in all the neuropsychological tests. A significant linear tendency (p trend < 0.05) was found between groups, with the aMCI-T2DM group presenting worse results in global cognition assessed by the Mini-Mental State Examination and Montreal Cognitive Assessment; Rey-Osterrieth Complex Figure Test; Auditory Verbal Learning Test; Trail Making Test A and B, Verbal Fluency Test, and Hamilton Depression Rating Scale. aMCI patients with or without diabetes showed worse cognitive function compared to persons without diabetes or aMCI. Additionally, aMCI patients without T2DM presented a different cognitive profile than aMCI patients with T2DM, which tended towards presenting worse cognitive functions such as global cognition, memory, attention, executive function, and language.

The Therapeutic Effects of Noninvasive Brain Stimulation Combined with Cognitive Training in Elders with Alzheimer's Disease or Amnesic Mild Cognitive Impairment.

Recent studies have indicated that noninvasive brain stimulation combined with cognitive interval (NIBS-CI) improved cognitive function in people with Alzheimer's disease (AD) or Amnesic mild cognitive impairment (a-MCI). While previous interventions have demonstrated that a single targeted cognitive intervention can improve cognitive function, the outcomes of using both interventions simultaneously are less well-established. Therefore, this study aims to perform a meta-analysis to determine the effectiveness of NIBS-CI in treating cognitive impairment associated with AD and a-MCI, with the goal of obtaining novel insights into this combined intervention. PubMed, Web of Science, ProQuest and Central Cochrane library databases were searched up to December 2022. The primary cognitive outcomes were extracted from the included article. A mean difference (MD) and standardized mean difference (SMD) with a 95% confidence interval were calculated by using random-effect models. Twelve studies with a total of 587 AD patients were included. The findings demonstrated that NIBS-CI significantly improved cognitive function of AD patients in cognitive outcomes (SMD = -0.52, 95%CI (-0. 93, -0.11)) and ADAS-COG (MD = -1.16, 95%CI (-1.69, -0.63)). The pooled results showed that NIBS-CI did not improve cognitive function of AD patients in short-time memory (SMD = 0.057, 95%CI (-0.13, 0.25), P = 0.56) and long-time memory (SMD = 0.001, 95%CI (-0.20, 0.20), P = 0.99). There is evidence for a positive effect of NIBS-CI on overall cognitive function of AD and a-MCI. Considering the limited sample size, it is important to interpret the findings related to memory with caution. To obtain more robust results, future studies should be conducted with larger sample sizes and incorporate objective neurophysiological and neuroimaging tools. These methodological enhancements will allow for a better understanding of the therapeutic targets and provide a more comprehensive assessment of the effects of NIBS-CI treatment.

Efficacy and safety of choline alfoscerate in the preventive therapy of dementia in elderly patients with Mild Cognitive Impairment: a three-year prospective comparative study

To study the efficacy and safety of the use of annual course therapy of choline alfoscerate (CA) as a drug potentially capable of slowing or preventing the transition of amnesic type mild cognitive impairment (aMCI) into clinically pronounced dementia in a three-year open comparative study, as well as to explore the possibility of predicting the preventive effect of such therapy based on a number of clinical and biological parameters. The study included 100 patients with aMCI, randomly divided into 2 groups: the therapeutic group consisted of 50 patients who received CA course therapy once a year for 3 years (20 intravenous infusions of 1000 mg (4 ml) in 100 ml of saline solution for 4 weeks) and a comparison group of 50 patients who underwent an annual examination at the center and did not receive therapy. Clinical and psychopathological, psychometric, immunological, follow-up, and statistical methods were used. A comparative three-year prospective study conducted in a group of aMCI patients treated with annual course therapy of CA for 3 years and aMCI patients who did not receive therapy with similar initial demographic, diagnostic, psychometric and immunological characteristics showed a lower progression of cognitive deficits (12.2% and 39.1%, respectively) and a lower conversion rate (8.2% and 26.1%, respectively) to dementia in the therapeutic group compared with the comparison group. The differences between the initial and final (after 1, 2 and 3 years of follow-up) cognitive functioning indicators in the therapeutic group and the comparison group were significant (p<0.05) on all scales and tests in favor of the therapeutic group throughout the entire follow-up period. The results allow us to consider CA as a possible model of preventive dementia therapy aimed at preventing the progression of cognitive deficits and the development of dementia in people at high risk of developing AD - patients with aMCI.

Regional amyloid‐β is linked to disruptions in connected speech in amnestic mild cognitive impairment

AbstractBackgroundSpeech changes in amnesic mild cognitive impairment (aMCI) are potential markers for the early detection of Alzheimer disease (AD). However, few studies investigate the relationship between speech and amyloid‐β burden. The focus of this study was to examine the relationship between the linguistic features and the distribution of amyloid‐β load in aMCI.MethodThis study recruited 25 aMCI patients (52% female, aged 70‐85 years) and 25 healthy elders (44% female, aged 68‐80 years) from the memory clinic of Cardinal Tian Hospital in Taiwan. All participants received [18F] florbetaben PET and standardized cognitive tests. Amyloid‐β load using a standardized uptake value ratio (SUVr) was estimated from 5 cortical regions (parietal, frontal, cingulate, temporal, and occipital). Spontaneous speech was recorded using the picture description task (three Taiwanese culture‐related pictures) and transcribed verbatim. Linguistic features were extracted, including lexical richness (total words, unique words, type‐token‐ratio, lexical density, and frequency), syntactic complexity (mean length of utterance/sentence, ratio of verbs/pronouns/passive sentence), and speech fluency (ratio of long pauses/ fillers).ResultEighteen subjects with high amyloid burden (SUVr &gt; 1.21) progressed (defined as CDR‐SB change≧1) within 1 year. We performed linear regression analyses between linguistic features (dependent variables, separate models) and amyloid‐β load in brain regions. Analyses were adjusted for age and education. The data revealed that a high amyloid‐β burden in the frontal region was associated with fewer unique words, less lexical density, and an increased proportion of long pauses and fillers. Reduced passive sentence, short mean length of utterance and lower scores on episodic memory tests related to increased amyloid‐β burden in the parietal region.ConclusionLexical richness and speech fluency was associated with amyloid‐β burden in the frontal region, indicating that voluntary lexical retrieval may require the additional recruitment of frontal lobe. Less syntactic complexity related to increased amyloid‐β burden in the parietal region. In conclusion, regional amyloid‐β is linked to subtle spontaneous speech deficits in aMCI.

The difference in apathy estimates between the patient and caregiver predicts dementia in individuals with amnestic MCI

AbstractBackgroundIn Alzheimer’s disease, apathy is a common behavioral sign (AD). The Apathy Evaluation Scale (AES) is a measure that investigates caregivers' (CG‐AES) and patients' (PT‐AES) perceptions of apathy, and the discrepancy in their evaluations is a proxy for patients' illness unawareness. We aimed to determine whether apathy and awareness of apathy predict dementia development and timing in a cohort study of individuals with amnesic mild cognitive impairment (aMCI).MethodWe acquired two main indices for analysis from the global AES scores of 110 patients with aMCI and their caregivers: i) ‘Apathy,’ the mean of PT‐AES and CG‐AES, and ii) ‘Discrepancy,’ obtained by subtracting CG‐AES from PT‐AES. Patients were seen every six months for three years, or until they developed dementia. The AES indices and the major demographical/neuropsychological variables were filtered for multicollinearity, and the most robust variables were entered into a logistic regression model and survival analyses (Cox regression, log‐rank test of Kaplan‐Meier curves) to estimate which variables predicted the risk and timing of progression, respectively.Result60 patients (54.5%) showed signs of dementia (57 AD) after 6.0‐36.0 months, whereas 28 patients (25.5%) dropped out and 22 patients (20%) were still in an MCI stage. The “Discrepancy” index was a reliable and accurate predictor of the probability of progression (AUC = 0.73) and, after binarization in accordance with a calculated cutoff, of the time to dementia.ConclusionA structured assessment of apathy, both by the patient and by the caregiver, can reveal important details about the likelihood and timing of the transition from aMCI to dementia. The difference between the two estimations serves as a reliable predictor of illness unawareness by patients.

The impact of amyloid‐PET and FDG‐PET on the progression from amnestic MCI to AD dementia in clinical practice

AbstractBackgroundAlzheimer disease (AD) is the most common cause of dementia worldwide. It is known that cerebral amyloid aggregation and neurodegeneration are first steps in the physiopathology of AD. In the prodromal phase, a clinical diagnosis of amnesic mild cognitive impairment (aMCI) can be stablished, but not all subjects with MCI have a prodromal AD. The objective of this study was to determinate the impact of amyloid and FDG PET on the progression from aMCI to AD dementia.MethodsFrom October 2013 to March 2021, we prospectively selected 145 patients with a diagnosis aMCI. We excluded subjects older than 85 and those with structural brain lesion on brain MRI. Participants went through an amyloid and an FDG‐PET scans and were classified as positive or negative for amyloid and neurodegeneration. Patients were followed to stablish progression to AD dementia, 118 patients were followed up more than 36 months. Statistical analyses were done with STATA with significance set at p&lt;0.05. All analyses were adjusted by age, gender, and education.ResultsDemographics are shown on table 1. Sensibility, specificity, negative predictive value, and positive predictive value during the 4 years are shown on table 2. 88 patients were A+ and 74 patients were A‐. We divided the patients in 4 groups: A+/FDG+ (n:54), A+/FDG‐ (n:34), A‐/FDG‐ (40), A‐/FDG+(4). The mean of conversion were 39.95 months, this time depends on the result of the biomarkers. A‐ patients converted less and latter with a mean of 75.07 (IC 56.54→81) month, than A+ patients, that converted earlier (chi2 = 20.37 Pr&gt;chi2 = 0.0000). A+/FDG+ converted with a mean of 27.79 (20.40‐33.21) months while A+/FDG‐ converted earlier with a mean of 37.38 (20.73‐48.26) month. (chi2 = 4.16 Pr&gt;chi2 = 0.0415).ConclusionsAmyloid and FDG PET can help us to stablish prognosis in aMCI patients. We have observed that a positive amyloid PET is associated with an increased risk of progression to AD dementia. Even more, aMCI patients with both, amyloid PET and FDG, positive PETs progressed more often and earlier to AD dementia than those who have a positive amyloid PET but a negative FDG‐PET.

Relationship between cognitive function and phase angle measured with a bioelectrical impedance system.

The purpose of this study was to investigate the relationship between cognitive function and phase angle (PhA), an indicator of muscle quality. This cross-sectional study enrolled outpatients who visited a memory clinic at the Nagoya University hospital from January 2016 to June 2022. We enrolled 153 participants with body composition measurements. Inclusion criteria were a Mini-Mental State Examination score of 20-30 and a clinical diagnosis of Alzheimer's dementia (AD) or amnesic mild cognitive impairment (aMCI). The background characteristics of the participants were compared according to AD and aMCI. Next, linear regression analysis was performed with PhA as the objective variable. In addition, logistic regression analysis was performed for AD diagnosis. PhA was lower in the AD group (P = 0.009). In linear regression analysis, PhA consistently decreased with worsening ADAS score. In logistic regression analysis, high PhA was associated with absence of AD. Gender-specific analyses showed these associations existed only in men. Our study of patients with AD and aMCI found that PhA decreased with worsening of cognitive function. Compared with aMCI, AD was associated with significantly lower PhA. Our results strengthen the limited evidence in the literature showing that low muscle quality is associated with poor cognitive function.

State-switching and high-order spatiotemporal organization of dynamic functional connectivity are disrupted by Alzheimer's disease.

Spontaneous activity during the resting state, tracked by BOLD fMRI imaging, or shortly rsfMRI, gives rise to brain-wide dynamic patterns of interregional correlations, whose structured flexibility relates to cognitive performance. Here, we analyze resting-state dynamic functional connectivity (dFC) in a cohort of older adults, including amnesic mild cognitive impairment (aMCI, N = 34) and Alzheimer's disease (AD, N = 13) patients, as well as normal control (NC, N = 16) and cognitively "supernormal" controls (SNC, N = 10) subjects. Using complementary state-based and state-free approaches, we find that resting-state fluctuations of different functional links are not independent but are constrained by high-order correlations between triplets or quadruplets of functionally connected regions. When contrasting patients with healthy subjects, we find that dFC between cingulate and other limbic regions is increasingly bursty and intermittent when ranking the four groups from SNC to NC, aMCI and AD. Furthermore, regions affected at early stages of AD pathology are less involved in higher order interactions in patient than in control groups, while pairwise interactions are not significantly reduced. Our analyses thus suggest that the spatiotemporal complexity of dFC organization is precociously degraded in AD and provides a richer window into the underlying neurobiology than time-averaged FC connections.

Association between vitamin E intake and mild cognitive impairment in people aged 55 years and older in Hebei Province

To investigate the relationship between dietary vitamin E(VE) intake and mild cognitive impairment(MCI). Based on the data of Hebei Province in the 2018 National Key Research and Development Program Nervous system disease CCSNSD, 612 subjects were included in this study. All study participants were surveyed for dietary VE intake by the Dietary Frequency Questionnaire and assessed for cognitive function by the Montreal Cognitive Assessment Scale. The relationship between dietary VE intake and MCI and its subtypes was analyzed using logistic regression and restricted cubic splines. The study subjects included 260(42.5%) males and 352(57.5%) females, with an average age of(66.8±7.4) years and an average dietary VE intake of(12.17±4.91) mg/d. The prevalence of cognitive impairment in the study population was 41.3%. After adjusting the covariates of age, gender, energy intake, residence, education level, employment status, BMI, smoking, drinking, physical activity, hypertension, diabetes, VE intake was not associated with the risk of non-amnesic(naMCI), single-domain amnesic(aMCI-SD), but relate to the risk of multi-domain amnesic(aMCI-MD). What&apos;s more, compared to dietary vitamin E intake Q1 group, the OR(95%CI) for multi-domain amnesic mild cognitive impairment in Q2, Q3 and Q4 groups were 1.628(0.836-3.170), 0.313(0.124-0.791) and 0.727(0.330-1.602), respectively. Using vitamin E intake as a continuous-type variable, a non-linear dose-response relationship was found between VE intake and mild cognitive dysfunction of the multi-domain amnesic type(P=0.02). When VE intake was about 17 mg/d, the risk of aMCI-MD was the lowest. There is an approximate &quot;U&quot; shaped dose-response relationship between dietary VE intake and the risk of mild cognitive impairment with multi-domain amnesia type. Research suggests that moderate VE intake has a preventive effect on the development of mild cognitive impairment.

The role of the sleep K-complex on the conversion from mild cognitive impairment to Alzheimer's disease.

The present literature points to an alteration of the human K-complex during non-rapid eye movement sleep in Alzheimer's disease. Nevertheless, the few findings on the K-complex changes in mild cognitive impairment and their possible predictive role on the Alzheimer's disease conversion show mixed findings, lack of replication, and a main interest for the frontal region. The aim of the present study was to assess K-complex measures in amnesic mild cognitive impairment subsequently converted in Alzheimer's disease over different cortical regions, comparing them with healthy controls and stable amnesic mild cognitive impairment. We assessed baseline K-complex density, amplitude, area under the curve and overnight changes in frontal, central and parietal midline derivations of 12 amnesic mild cognitive impairment subsequently converted in Alzheimer's disease, 12 stable amnesic mild cognitive impairment and 12 healthy controls. We also assessed delta electroencephalogram power, to determine if K-complex alterations in amnesic mild cognitive impairment occur with modification of the electroencephalogram power in the frequency range of the slow-wave activity. We found a reduced parietal K-complex density in amnesic mild cognitive impairment subsequently converted in Alzheimer's disease compared with stable amnesic mild cognitive impairment and healthy controls, without changes in K-complex morphology and overnight modulation. Both amnesic mild cognitive impairment groups showed decreased slow-wave sleep percentage compared with healthy controls. No differences between groups were observed in slow-wave activity power. Our findings suggest that K-complex alterations in mild cognitive impairment may be observed earlier in parietal regions, likely mirroring the topographical progression of Alzheimer's disease-related brain pathology, and express a frontal predominance only in a full-blown phase of Alzheimer's disease. Consistently with previous results, such K-complex modification occurs in the absence of significant electroencephalogram power changes in the slow oscillations range.

Functional changes in the salience network of patients with amnesic mild cognitive impairment before and after repetitive transcranial magnetic stimulation.

Amnestic mild cognitive impairment (aMCI) is considered to be the prodromal stage of Alzheimer's disease (AD). The precuneus (PCUN) may be an imaging marker for monitoring the progression of AD. Meanwhile, cognitive impairment in AD patients is closely related to functional connectivity (FC) changes in the salience network (SN). We hypothesize that there are specific neuroimaging biomarkers in the SN and that FC changes in aMCI patients after repetitive transcranial magnetic stimulation (rTMS) intervention are associated with cognitive function. The purpose of this study was to first investigate the pattern of functional changes in aMCI patients and healthy controls (HCs) and then compare the functional changes in aMCI patients before and after rTMS targeting to PCUN and its correlation with cognitive function. Thirty-six HCs and 61 aMCIs were recruited for our study. Eleven people in the aMCI group received rTMS intervention 5 days a week for 4 weeks. Using the right anterior insula as the seed-of-interest, we first compared FC changes in HC and aMCI patients and then compared cognitive function in aMCI patients before and after rTMS. The above is the functional connection analysis of seed-to-voxel. Moreover, we investigated the FC changes in aMCI patients after rTMS intervention and its correlation with cognitive function. Compared with HC, the aMCI group showed altered FC in bilateral parahippocampal gyrus, bilateral inferior parietal lobule, left middle frontal gyrus, and left middle temporal gyrus. Moreover, rTMS at PCUN improved the cognitive function of aMCI patients, which was related to the altered FC in posterior cerebellar lobes (CPL). Our findings suggest that rTMS targeting PCUN is a promising, noninvasive approach to ameliorating cognitive dysfunction in aMCI patients, and that this cognitive improvement is accompanied by brain connectivity modulation.

Changes in Plasma Amyloid-β Level and Their Relationship With White Matter Microstructure in Patients With Mild Cognitive Impairment

Objective To investigate the changes in plasma amyloid-β (Aβ) level and their relationship with white matter microstructure in the patients with amnesic mild cognitive impairment(aMCI) and vascular mild cognitive impairment (vMCI).Methods A total of 36 aMCI patients,20 vMCI patients,and 34 sex and age matched healthy controls (HC) in the outpatient and inpatient departments of the First Affiliated Hospital of Anhui Medical University were enrolled in this study.Neuropsychological scales,including the Mini-Mental State Examination,the Montreal Cognitive Assessment,and the Activity of Daily Living Scale,were employed to assess the participants.Plasma samples of all the participants were collected for the measurement of Aβ42 and Aβ40 levels.All the participants underwent magnetic resonance scanning to obtain diffusion tensor imaging (DTI) data.The DTI indexes of 48 white matter regions of each individual were measured (based on the ICBM-DTI-81 white-matter labels atlas developed by Johns Hopkins University),including fractional anisotropy (FA) and mean diffusivity (MD).The cognitive function,plasma Aβ42,Aβ40,and Aβ42/40 levels,and DTI index were compared among the three groups.The correlations between the plasma Aβ42/40 levels and DTI index of aMCI and vMCI patients were analyzed.Results The Mini-Mental State Examination and the Montreal Cognitive Assessment scores of aMCI and vMCI groups were lower than those of the HC group (all P<0.001).There was no significant difference in the Activity of Daily Living Scale score among the three groups (P=0.654).The plasma Aβ42 level showed no significant difference among the three groups (P=0.227).The plasma Aβ40 level in the vMCI group was higher than that in the HC group (P=0.014),while it showed no significant difference between aMCI and HC groups (P=1.000).The plasma Aβ42/40 levels in aMCI and vMCI groups showed no significant differences from that in the HC group (P=1.000,P=0.105),while the plasma Aβ42/40 level was lower in the vMCI group than in the aMCI group (P=0.016).The FA value of the left anterior limb of internal capsule in the vMCI group was lower than those in HC and aMCI groups (all P=0.001).The MD values of the left superior corona radiata,left external capsule,left cingulum (cingulate gyrus),and left superior fronto-occipital fasciculus in the vMCI group were higher than those in HC (P=0.024,P=0.001,P=0.003,P<0.001) and aMCI (P=0.015,P=0.004,P=0.019,P=0.001) groups,while the MD values of the right posterior limb of internal capsule (P=0.005,P=0.001) and left cingulum (hippocampus) (P=0.017,P=0.031) in the aMCI and vMCI groups were higher than those in the HC group.In the aMCI group,plasma Aβ42/40 level was positively correlated with FA of left posterior limb of internal capsule (r=0.403,P=0.015) and negatively correlated with MD of the right fonix (r=-0.395,P=0.017).In the vMCI group,plasma Aβ42/40 level was positively correlated with FA of the right superior cerebellar peduncle and the right anterior limb of internal capsule (r=0.575,P=0.008;r=0.639,P=0.002),while it was negatively correlated with MD of the right superior cerebellar peduncle and the right anterior limb of internal capsule (r=-0.558,P=0.011;r=-0.626,P=0.003).Conclusions Plasma Aβ levels vary differently in the patients with aMCI and vMCI.The white matter regions of impaired microstructural integrity differ in the patients with different dementia types in the early stage.The plasma Aβ levels in the patients with aMCI and vMCI are associated with the structural integrity of white matter,and there is regional specificity between them.

Telemedicine for cognitive impairment: a telephone survey of patients’ experiences with neurological video consultation

ObjectiveThis study aimed to evaluate the experience with telemedicine in patients with cognitive impairments and their caregivers.MethodsWe conducted a survey-based study of patients who completed neurological consultation via video link between January and April 2022.ResultsA total of 62 eligible neurological video consultations were conducted for the following categories of patients: Alzheimer’s disease (33.87%), amnesic mild cognitive impairment (24.19%), frontotemporal dementia (17.74%), Lewy body dementia (4.84%), mixed dementia (3.23%), subjective memory disorders (12.90%), non-amnesic mild cognitive impairment (1.61%), and multiple system atrophy (1.61%).The survey was successfully completed by 87.10% of the caregivers and directly by the patients in 12.90% of cases. Our data showed positive feedback regarding the telemedicine experience; both caregivers and patients reported that they found neurological video consultation useful (caregivers: 87.04%, ‘very useful’; patients: 87.50%, ‘very useful’) and were satisfied overall (caregivers: 90.74%, ‘very satisfied’; patients: 100%, ‘very satisfied’). Finally, all caregivers (100%) agreed that neurological video consultation was a useful tool to reduce their burden (Visual Analogue Scale mean ± SD: 8.56 ± 0.69).ConclusionsTelemedicine is well received by patients and their caregivers. However, successful delivery incorporates support from staff and care partners to navigate technologies. The exclusion of older adults with cognitive impairment in developing telemedicine systems may further exacerbate access to care in this population. Adapting technologies to the needs of patients and their caregivers is critical for the advancement of accessible dementia care through telemedicine.

The predictability and plausibility effects on N400 reflect the language deficit in patients with mild cognitive impairment

AbstractBackgroundReliable markers of language decline in patients with amnesic mild cognitive impairment (aMCI) are critical for the early detection of Alzheimer’s disease. However, language impairments may be subtle and difficult to be detected from behavioral performance measures. N400 is an Event‐Related Potentials (ERP) component to index the semantic processing and has been used to reflect the deficit of language comprehension in aphasic patients (Chang et al., 2016). This study manipulated the predictability and plausibility of the Chinese classifier‐noun agreement to examine whether these two effects on N400 may serve as potential markers for the early detection of aMCI.MethodThis study recruited 16 MCI patients and 17 age‐matched healthy elders from the memory clinic of Cardinal Tian Hospital in Taiwan. All participants received [18F] florbetaben PET and a set of standardized cognitive tests, including Mini‐Mental State Examination (MMSE), verbal fluency, and Wechsler Memory Scale‐III (WMS‐III), for MCI diagnosis. The positivity rate of the aMCI group was 43.75%, and 31.25% for the healthy elder group. During the ERP recording, participants would read a series of classifier‐noun phrases, and each classifier was paired with a highly predictable, a low predictable, or an implausible noun.ResultWe performed the Linear mixed models to examine whether the predictability effect (high vs. low predictable nouns) and plausibility effect (high vs. implausible nouns) on N400 (300‐500ms) would be explained by the particpants’ cognitive performance. The data revealed that participants with higher scores of MMSE (b = ‐0.019, SE = 0.010, t = ‐1.969), verbal fluency (b = ‐0.023, SE = 0.008, t = ‐2.781), and WMS‐III (b = ‐0.002, SE = 0.001, t = ‐2.370) showed more pronounced predictability effects, which reflecting better semantic integration processing. Meanwhile, participants with poor memory engendered a reduced plausibility effect (b = ‐0.004, SE = 0.001, t = ‐3.972).ConclusionOur findings suggest that MCI patients would exhibit a deficit in semantic process. The predictability and plausibility effects on N400 may serve as ERPs markers to detect the language deficits in aMCI.

Discrepancy Between Patient and Caregiver Estimate of Apathy Predicts Dementia in Patients with Amnestic Mild Cognitive Impairment.

Apathy is a frequent behavioral symptom of Alzheimer's disease (AD). The Apathy Evaluation Scale (AES) is a tool exploring the perception of apathy by both caregivers (CG-AES) and patients (PT-AES), and the discrepancy in their ratings is a proxy of patients' disease unawareness. To assess in a cohort study of patients with amnesic mild cognitive impairment (aMCI) whether apathy and awareness of apathy predict progression to dementia and timing. From the global AES scores of 110 patients with aMCI and their caregivers, we obtained two principal indices for analysis: 1) 'Apathy', the mean of PT-AES and CG-AES, and 2) 'Discrepancy', obtained by subtracting CG-AES from PT-AES. Patients were followed with visits every six months for three years or until dementia. AES indices and the principal demographical/neuropsychological variables were filtered from multicollinearity. The most robust variables entered a logistic regression model and survival analyses (Cox regression, log-rank test of Kaplan-Meier curves) to estimate which predicted the risk and timing of progression, respectively. Sixty patients (54.5%) developed dementia (57 AD) after 6.0-36.0 months, 22 (20%) remained in an MCI stage, and 28 (25.5%) dropped out. 'Discrepancy' was a robust and accurate predictor of the risk of progression (AUC = 0.73) and, after binarization according to a computed cutoff, of timing to dementia. A structured evaluation of apathy, both self-assessed and estimated by caregivers, can provide useful information on the risk and timing of progression from aMCI to dementia. The discrepancy between the two estimates is a fairly reliable index for prediction purposes as a proxy of disease unawareness.

Visual-spatial processing impairment in the occipital-frontal connectivity network at early stages of Alzheimer's disease.

Alzheimer's disease (AD) is the leading cause of dementia worldwide, but its pathophysiological phenomena are not fully elucidated. Many neurophysiological markers have been suggested to identify early cognitive impairments of AD. However, the diagnosis of this disease remains a challenge for specialists. In the present cross-sectional study, our objective was to evaluate the manifestations and mechanisms underlying visual-spatial deficits at the early stages of AD. We combined behavioral, electroencephalography (EEG), and eye movement recordings during the performance of a spatial navigation task (a virtual version of the Morris Water Maze adapted to humans). Participants (69-88 years old) with amnesic mild cognitive impairment-Clinical Dementia Rating scale (aMCI-CDR 0.5) were selected as probable early AD (eAD) by a neurologist specialized in dementia. All patients included in this study were evaluated at the CDR 0.5 stage but progressed to probable AD during clinical follow-up. An equal number of matching healthy controls (HCs) were evaluated while performing the navigation task. Data were collected at the Department of Neurology of the Clinical Hospital of the Universidad de Chile and the Department of Neuroscience of the Faculty of Universidad de Chile. Participants with aMCI preceding AD (eAD) showed impaired spatial learning and their visual exploration differed from the control group. eAD group did not clearly prefer regions of interest that could guide solving the task, while controls did. The eAD group showed decreased visual occipital evoked potentials associated with eye fixations, recorded at occipital electrodes. They also showed an alteration of the spatial spread of activity to parietal and frontal regions at the end of the task. The control group presented marked occipital activity in the beta band (15-20 Hz) at early visual processing time. The eAD group showed a reduction in beta band functional connectivity in the prefrontal cortices reflecting poor planning of navigation strategies. We found that EEG signals combined with visual-spatial navigation analysis, yielded early and specific features that may underlie the basis for understanding the loss of functional connectivity in AD. Still, our results are clinically promising for early diagnosis required to improve quality of life and decrease healthcare costs.

Sex Difference in General Cognition Associated with Coupling of Whole-brain Functional Connectivity Strength to Cerebral Blood Flow Changes During Alzheimer’s Disease Progression

Alzheimer’s disease (AD) is a progressive age-related neurodegenerative disorder that results in irreversible cognitive impairments. Nonetheless, there are numerous sex-dependent differences in clinical course. We examined potential contributions of neurovascular coupling deficits to sex differences in AD progression. T1-weighted three-dimensional structural magnetic resonance images, functional blood oxygen level dependent and arterial spin labeling images were acquired from 50 AD patients (28 females), 52 amnesic mild cognitive impairment patients (31 females), and 59 healthy controls (36 females). Short- and long-range functional connectivity strength (FCS) and cerebral blood flow (CBF) values were calculated for all participants. Then, the CBF/FCS coupling ratio, which represented the amount of blood supply per unit of connectivity strength, was calculated for each voxel. Two-way ANOVA was performed to identify group × sex interactions and main effects of group. Correlation analysis was used to assess associations between CBF/FCS ratios and Mini-Mental State Examination (MMSE). There were significant group × sex interaction effects on short-range coupling ratios of right middle temporal gyrus, left angular gyrus, left inferior orbital frontal gyrus, and left superior frontal gyrus as well as on the long-range coupling ratios of right middle temporal gyrus, left precuneus, left posterior cingulate cortex, and left angular gyrus. There were significant negative correlations between MMSE scores and CBF/FCS ratios for all regions with significant group × sex interactions among female patients, while positive correlations were found among male patients. Our results demonstrate significant sex differences in neurovascular coupling mechanisms associated with cognitive function during the course of AD.

Relevance of plasma biomarkers to pathologies in Alzheimer’s disease, Parkinson’s disease and frontotemporal dementia

Amyloid plaques and tau tangles are pathological hallmarks of Alzheimer’s disease (AD). Parkinson’s disease (PD) results from the accumulation of α-synuclein. TAR DNA-binding protein (TDP-43) and total tau protein (T-Tau) play roles in FTD pathology. All of the pathological evidence was found in the biopsy. However, it is impossible to perform stein examinations in clinical practice. Assays of biomarkers in plasma would be convenient. It would be better to investigate the combinations of various biomarkers in AD, PD and FTD. Ninety-one subjects without neurodegenerative diseases, 76 patients with amnesic mild cognitive impairment (aMCI) or AD dementia, combined as AD family, were enrolled. One hundred and nine PD patients with normal cognition (PD-NC) or dementia (PDD), combined as PD family, were enrolled. Twenty-five FTD patients were enrolled for assays of plasma amyloid β 1–40 (Aβ1–40), Aβ1–42, T-Tau, α-synuclein and TDP-43 using immunomagnetic reduction (IMR). The results show that Aβs and T-Tau are major domains in AD family. α-synuclein is highly dominant in PD family. FTD is closely associated with TDP-43 and T-Tau. The dominant plasma biomarkers in AD family, PD family and FTD are consistent with pathology. This implies that plasma biomarkers are promising for precise and differential assessments of AD, PD and FTD in clinical practice.

Connectivity alterations underlying the breakdown of pseudoneglect: New insights from healthy and pathological aging.

A right-hemisphere dominance for visuospatial attention has been invoked as the most prominent neural feature of pseudoneglect (i.e., the leftward visuospatial bias exhibited in neurologically healthy individuals) but the neurophysiological underpinnings of such advantage are still controversial. Previous studies investigating visuospatial bias in multiple-objects visual enumeration reported that pseudoneglect is maintained in healthy elderly and amnesic mild cognitive impairment (aMCI), but not in Alzheimer’s disease (AD). In this study, we aimed at investigating the neurophysiological correlates sustaining the rearrangements of the visuospatial bias along the progression from normal to pathological aging. To this aim, we recorded EEG activity during an enumeration task and analyzed intra-hemispheric fronto-parietal and inter-hemispheric effective connectivity adopting indexes from graph theory in patients with mild AD, patients with aMCI, and healthy elderly controls (HC). Results revealed that HC showed the leftward bias and stronger fronto-parietal effective connectivity in the right as compared to the left hemisphere. A breakdown of pseudoneglect in patients with AD was associated with both the loss of the fronto-parietal asymmetry and the reduction of inter-hemispheric parietal interactions. In aMCI, initial alterations of the attentional bias were associated with a reduction of parietal inter-hemispheric communication, but not with modulations of the right fronto-parietal connectivity advantage, which remained intact. These data provide support to the involvement of fronto-parietal and inter-parietal pathways in the leftward spatial bias, extending these notions to the complex neurophysiological alterations characterizing pathological aging.