Verbal fluency performance in amnestic MCI and older adults with cognitive complaints

Verbal fluency tests are employed regularly during neuropsychological assessments of older adults, and deficits are a common finding in patients with Alzheimer's disease (AD). Little extant research, however, has investigated verbal fluency ability and subtypes in preclinical stages of neurodegenerative disease. We examined verbal fluency performance in 107 older adults with amnestic mild cognitive impairment (MCI, n = 37), cognitive complaints (CC, n = 37) despite intact neuropsychological functioning, and demographically matched healthy controls (HC, n = 33). Participants completed fluency tasks with letter, semantic category, and semantic switching constraints. Both phonemic and semantic fluency were statistically (but not clinically) reduced in amnestic MCI relative to cognitively intact older adults, indicating subtle changes in the quality of the semantic store and retrieval slowing. Investigation of the underlying constructs of verbal fluency yielded two factors: Switching (including switching and shifting tasks) and Production (including letter, category, and action naming tasks), and both factors discriminated MCI from HC albeit to different degrees. Correlational findings further suggested that all fluency tasks involved executive control to some degree, while those with an added executive component (i.e., switching and shifting) were less dependent on semantic knowledge. Overall, our findings highlight the importance of including multiple verbal fluency tests in assessment batteries targeting preclinical dementia populations and suggest that individual fluency tasks may tap specific cognitive processes.     

PET imaging of amyloid deposition in patients with mild cognitive impairment

It is of great clinical value to identify subjects at a high risk of developing AD. We previously found that the amyloid positron emission tomography (PET) tracer PIB showed a robust difference in retention in the brain between AD patients and healthy controls (HC). Twenty-one patients diagnosed with MCI (mean age 63.3 ± 7.8 (S.D.) years) underwent PET studies with ¹¹C-PIB, and ¹⁸F-fluoro-deoxy-glucose (FDG) to measure cerebral glucose metabolism, as well as assessment of cognitive function and CSF sampling. Reference group data from 27 AD patients and 6 healthy controls, respectively, were used for comparison. The mean cortical PIB retention for the MCI patients was intermediate compared to HC and AD. Seven MCI patients that later at clinical follow-up converted to AD (8.1 ± 6.0 (S.D.) months) showed significant higher PIB retention compared to non-converting MCI patients and HC, respectively (ps < 0.01). The PIB retention in MCI converters was comparable to AD patients (p > 0.01). Correlations were observed in the MCI patients between PIB retention and CSF Aβ_1-42, total Tau and episodic memory, respectively.     

Measurements of medial temporal lobe atrophy for prediction of Alzheimer's disease in subjects with mild cognitive impairment

Our aim was to compare the predictive accuracy of 4 different medial temporal lobe measurements for Alzheimer's disease (AD) in subjects with mild cognitive impairment (MCI). Manual hippocampal measurement, automated atlas-based hippocampal measurement, a visual rating scale (MTA-score), and lateral ventricle measurement were compared. Predictive accuracy for AD 2 years after baseline was assessed by receiver operating characteristics analyses with area under the curve as outcome. Annual cognitive decline was assessed by slope analyses up to 5 years after baseline. Correlations with biomarkers in cerebrospinal fluid (CSF) were investigated. Subjects with MCI were selected from the Development of Screening Guidelines and Clinical Criteria for Predementia AD (DESCRIPA) multicenter study (n = 156) and the single-center VU medical center (n = 172). At follow-up, area under the curve was highest for automated atlas-based hippocampal measurement (0.71) and manual hippocampal measurement (0.71), and lower for MTA-score (0.65) and lateral ventricle (0.60). Slope analysis yielded similar results. Hippocampal measurements correlated with CSF total tau and phosphorylated tau, not with beta-amyloid 1–42. MTA-score and lateral ventricle volume correlated with CSF beta-amyloid 1–42. We can conclude that volumetric hippocampal measurements are the best predictors of AD conversion in subjects with MCI.     

Associations between sleep duration and cognitive impairment in mild cognitive impairment

The prevalence of mild cognitive impairment (MCI) increases among elderly people and is associated with a high risk of dementia. Identifying factors that may contribute to the progress of MCI to dementia is critical. The objective of this study was to examine the association of objective sleep with cognitive performance in MCI patients. A subsample of 271 participants with a diagnosis of probable Alzheimer's disease (AD; N = 50) or mild cognitive impairment (MCI; N = 121) and 100 persons who were not cognitively impaired (NI) were recruited from a large population‐based cohort in the island of Crete, Greece (3140 older adults aged >60 years). All participants underwent extensive neuropsychiatric/neuropsychological evaluation and a 3‐day 24‐hr actigraphy. Objective sleep variables and their association with neuropsychological performance were examined across the three groups, controlling for demographics, body mass index, depression, sleep apnea symptoms and psychotropic medications. Patients with AD had significantly longer 24‐hr total sleep time (TST) compared to the MCI and NI groups. Long 24‐hr TST was associated with reduced performance on tasks that placed significant demands on attention and processing speed in the MCI group and the AD group. Elderly patients with MCI have similar objective sleep duration to normal controls, whereas AD patients sleep longer. Long sleep duration in patients with multidomain subtypes of MCI is associated with critical non‐memory cognitive domains. It appears that within the MCI group those that sleep longer have more severe cognitive impairment.     

40-Hz steady state response in Alzheimer's disease and mild cognitive impairment

The 40-Hz steady state response (SSR) reflects early sensory processing and can be measured with electroencephalography (EEG). The current study compared the 40-Hz SSR in groups consisting of mild Alzheimer's disease patients (AD) (n = 15), subjects with mild cognitive impairment (MCI) (n = 20) and healthy elderly control subjects (n = 20). All participants were naïve for psychoactive drugs. Auditory click trains at a frequency of 40-Hz evoked the 40-Hz SSR. To evaluate test-retest reliability (TRR), subjects underwent a similar assessment 1 week after the first. The results showed a high TRR and a significant increase of 40-Hz SSR power in the AD group compared to MCI and controls. Furthermore a moderate correlation between 40-Hz SSR power and cognitive performance as measured by ADAS-cog was shown.The results suggest that 40-Hz SSR might be an interesting candidate marker of disease progression.     

The impact of cognitive training and mental stimulation on cognitive and everyday functioning of healthy older adults: A systematic review and meta-analysis

This systematic review and meta-analysis investigates the impact of cognitive training and general mental stimulation on the cognitive and everyday functioning of older adults without known cognitive impairment. We examine transfer and maintenance of intervention effects, and the impact of training in group versus individual settings. Thirty-one randomised controlled trials were included, with 1806 participants in cognitive training groups and 386 in general mental stimulation groups. Meta-analysis results revealed that compared to active controls, cognitive training improved performance on measures of executive function (working memory, p = 0.04; processing speed, p < 0.0001) and composite measures of cognitive function (p = 0.001). Compared to no intervention, cognitive training improved performance on measures of memory (face-name recall, p = 0.02; immediate recall, p = 0.02; paired associates, p = 0.001) and subjective cognitive function (p = 0.01). The impact of cognitive training on everyday functioning is largely under investigated. More research is required to determine if general mental stimulation can benefit cognitive and everyday functioning. Transfer and maintenance of intervention effects are most commonly reported when training is adaptive, with at least ten intervention sessions and a long-term follow-up. Memory and subjective cognitive performance might be improved by training in group versus individual settings.     

Assessment of ZnT3 and PSD95 protein levels in Lewy body dementias and Alzheimer's disease: association with cognitive impairment

The loss of zinc transporter 3 (ZnT3) has been implicated in age-related cognitive decline in mice, and the protein has been associated with plaques. We investigated the levels of ZnT3 and postsynaptic density protein 95 (PSD95), a marker of the postsynaptic terminal, in people with Parkinson's disease dementia (PDD, n = 31), dementia with Lewy bodies (DLB, n = 44), Alzheimer's disease (AD, n = 16), and controls (n = 24), using semiquantitative western blotting and immunohistochemistry in 3 cortical regions. Standardized cognitive assessments during life and semiquantitative scoring of amyloid β (Aβ), tau, and α-synuclein at postmortem were used to investigate the relationship between ZnT3 and PSD95, cognition and pathology. Associations were observed between ZnT3 and PSD95 levels in prefrontal cortex and cognitive impairment (p = 0.001 and p = 0.002, respectively) and between ZnT3 levels in the parietal cortex and cognitive impairment (p = 0.036). Associations were also seen between ZnT3 levels in cingulate cortex and severity of Aβ (p = 0.003) and tau (p = 0.011) pathologies. DLB and PDD were characterized by significant reductions of PSD95 (p < 0.05) and ZnT3 (p < 0.001) in prefrontal cortex compared with controls and AD. PSD95 levels in the parietal cortex were found to be decreased in AD cases compared with controls (p = 0.02) and PDD (p = 0.005). This study has identified Zn²⁺ modulation as a possible novel target for the treatment of cognitive impairment in DLB and PDD and the potential for synaptic proteins to be used as a biomarker for the differentiation of DLB and PDD from AD.     

Sex differences in the prevalence and incidence of mild cognitive impairment: A meta-analysis

ObjectiveMore women have Alzheimer’s disease (AD) than men. Understanding sex differences in mild cognitive impairment (MCI) may further knowledge of AD etiology and prevention. We conducted a meta-analysis to examine sex differences in the prevalence and incidence of MCI, which included amnestic and non-amnestic subtypes.MethodSystematic searches were performed in July 2015 using MEDLINE/PubMed, Scopus, and PsycINFO for population-or community-based studies with MCI data for men and women. Random-effects model were used.ResultsFifty-six studies were included. There were no statistically significant sex differences in prevalence or incidence of amnestic MCI. There was a significantly higher prevalence (p = 0.038), but not incidence, of non-amnestic MCI among women. There were no sex differences in studies that combined both subtypes of MCI.ConclusionThe only statistically significant finding emerging from this study was that women have a higher prevalence of non-amnestic MCI. To better understand sex differences in the preclinical stages of dementia, studies must better characterize the etiology of the cognitive impairment.     

Reduced levels of IgM autoantibodies against N-truncated pyroglutamate Aβ in plasma of patients with Alzheimer's disease

In the present work, we investigated the level of IgM autoantibodies directed against different Aβ epitopes as potential diagnostic biomarker for Alzheimer's disease (AD). Anti-Aβ autoantibody levels were measured in 75 plasma samples from patients with AD, individuals with mild cognitive impairment (MCI), and healthy age- and sex-matched controls (HC). To validate the presence of anti-Aβ IgMs, pooled plasma samples were subjected to gel-filtration analysis. The mean level of pGluAβ-IgM (N-terminal truncated starting at position three with pyroglutamate) was significantly decreased in AD patients as compared to HC. In the group of MCI patients there was a significant positive correlation between pGluAβ-IgM and cognitive decline analyzed by MMSE (rho = 0.58, d.f. = 13, p = 0.022). These observations indicate that the level of IgM autoantibodies against pGluAβ is a promising plasma biomarker for AD and correlates with the cognitive status of individuals at risk to develop AD.     

MCI patients’ EEGs show group differences between those who progress and those who do not progress to AD

The theta/gamma and alpha3/alpha2 ratio were investigated as early markers for prognosticating of progression to dementia. 76 subjects with mild cognitive impairment (MCI) underwent EEG recording, MRI scans and neuropsychological (NPS) tests. After 3 years of follow-up, three subgroups were characterized as converters to Alzheimer's disease (AD, N = 18), converters to non-AD dementia (N = 14) and non-converters (N = 44). The theta/gamma and alpha3/alpha2 ratio, performance on cognitive tests and hippocampal volume, as evaluated at the time of initial MCI diagnosis, were studied in the three groups. As expected, MCI to AD converters had the smallest mean hippocampal volume and poorest performance on verbal learning tests, whereas MCI to non-AD converters had poorest cognitive performance in non-verbal learning tests, abstract thinking, and letter fluency. Increased theta/gamma ratio was associated with conversion to both AD and non-AD dementia; increased alpha3/alpha2 ratio was only associated with conversion to AD.Theta/gamma and alpha3/alpha2 ratio could be promising prognostic markers in MCI patients. In particular, the increase of high alpha frequency seems to be associated with conversion in AD. EEG markers allow a mean correct percentage of correct classification up to 88.3%. Future prospective studies are needed to evaluate the sensitivity and specificity of these measures for predicting an AD outcome.     

Neutrophil activation in Alzheimer’s disease and mild cognitive impairment: A systematic review and meta-analysis of protein markers in blood and cerebrospinal fluid

Inflammation is involved in the pathophysiology of Alzheimer’s disease (AD), with multiple inflammatory processes implicated in its risk and progression. This review included original peer-reviewed studies measuring the cerebrospinal fluid or peripheral blood concentrations of protein markers specifically related to neutrophil activity in healthy controls (HC) and in patients with AD or mild cognitive impairment (MCI). A total of 35 studies (N_HC = 3095, N_AD = 2596, N_MCI = 1203) were included. Random-effects meta-analyses were used to estimate between-groups standardized mean differences (SMD) and 95 % confidence intervals. In blood, concentrations of myeloperoxidase (MPO; N_AD/N_HC = 271/209, SMD = 0.41 [0.20, 0.62]; I² = 15.7 %) and neutrophil gelatinase associated lipocalin (NGAL; N_AD/N_HC = 273/185, SMD = 0.30 [0.11, 0.49]; I² < 0.005 %) were significantly higher in AD relative to HC. Peripheral blood concentrations of NGAL were also higher in MCI compared to HC (N_MCI/N_HC = 489/145, SMD = 0.39 [0.11, 0.67]; I² = 38.6 %). None of the protein markers exhibited a significant difference between HC, MCI, or AD groups in the cerebrospinal fluid. The evidence suggests that peripheral neutrophil activation, as indicated by blood concentrations of NGAL and MPO, may be a pathological feature of cognitive impairment due to AD, evident at stages of MCI and AD dementia.     

Self- and informant reports of executive function on the BRIEF-A in MCI and older adults with cognitive complaints.

Amnestic mild cognitive impairment (MCI) is characterized by impaired episodic memory, although subtle executive problems have been noted on neuropsychological tests. Recent research also has described a group of healthy, non-depressed older adults with significant cognitive complaints (CC) but normal performance on neuropsychological testing. These individuals show structural and functional brain changes intermediate between those seen in MCI and healthy older adults without such complaints (HC). We evaluated executive functions in MCI and CC using the Behavior Rating Inventory of Executive Function-Adult version (BRIEF-A), a newly developed self- and informant report questionnaire in 29 patients with amnestic MCI, 28 CCs, and 30 demographically matched HCs. MCI and CC participants reported significant difficulties with selective aspects of executive functioning relative to HCs despite clinically normal performance on neuropsychological tests of this cognitive domain. Scores were generally in the pattern of MCI>CC>HC, and findings were most pronounced for working memory. Additionally, MCI and CC participants were more likely than their informants to report clinically meaningful executive problems, though informants identified a similar pattern of difficulty overall. Results failed to reveal strong relations between the BRIEF-A and standardized neuropsychological tests of executive function. Overall findings indicate that the BRIEF-A is sensitive to subtle executive changes in MCI and CC and suggest the need for research to determine if executive complaints are predictive of clinical course.     

Cingulum fiber diffusivity and CSF T-tau in patients with subjective and mild cognitive impairment

Diffusion tensor imaging (DTI) and CSF biomarkers are useful diagnostic tools to differentiate patients with mild cognitive impairment (MCI) from normal controls, and may help predict conversion to dementia. Total Tau protein (T-tau) and DTI parameters are both markers for axonal damage, thus it is of interest to determine if DTI parameters are associated with elevated CSF T-tau levels in patients with cognitive impairment. For this purpose, patients with subjective cognitive impairment (SCI) and MCI were recruited from a university based memory clinic.Regions of interest were used to determine fractional anisotropy (FA), radial diffusivity (DR) and axial diffusivity (DA) in known white matter tracts in patients with MCI (n = 39) and SCI (n = 8) and 26 cognitively healthy controls. Significant lower FA and higher DR values were observed in patients with pathological vs. patients with normal CSF T-tau levels and vs. controls in left posterior cingulum fibers. T-tau values were negatively correlated with FA and positively correlated with DR values in the posterior cingulum fibers.Cingulum fiber diffusivity was related to T-tau pathology in SCI/MCI patients and altered DR may suggest that loss of myelin contributes to early white matter changes in patients at risk of developing Alzheimer's disease (AD).     

Regionally specific atrophy of the corpus callosum in AD, MCI and cognitive complaints

The goal of the present study was to determine if there are global or regionally specific decreases in callosal area in early Alzheimer's disease (AD) and mild cognitive impairment (MCI). In addition, this study examined the corpus callosum of healthy older adults who have subjective cognitive complaints (CC) but perform within normal limits on neuropsychological tests. We used a semi-automated procedure to examine the total and regional areas of the corpus callosum in 22 patients with early AD, 28 patients with amnestic MCI, 28 healthy older adults with cognitive complaints, and 50 demographically matched healthy controls (HC). The AD, MCI, and CC groups all showed a significant reduction of the posterior region (isthmus and splenium) relative to healthy controls. The AD group also had a significantly smaller overall callosum than the controls. The demonstration of callosal atrophy in older adults with cognitive complaints suggests that callosal changes occur very early in the dementing process, and that these earliest changes may be too subtle for detection by neuropsychological assessments, including memory tests.     

Reduced plasticity and mild cognitive impairment-like deficits after entorhinal lesions in hAPP/APOE4 mice

Mild cognitive impairment (MCI) is a clinical condition that often precedes Alzheimer disease (AD). Compared with apolipoprotein E-ε3 (APOE3), the apolipoprotein E-ε4 (APOE4) allele is associated with an increased risk of developing MCI and spatial navigation impairments. In MCI, the entorhinal cortex (EC), which is the main innervation source of the dentate gyrus, displays partial neuronal loss. We show that bilateral partial EC lesions lead to marked spatial memory deficits and reduced synaptic density in the dentate gyrus of APOE4 mice compared with APOE3 mice. Genotype and lesion status did not affect the performance in non-navigational tasks. Thus, partial EC lesions in APOE4 mice were sufficient to induce severe spatial memory impairments and synaptic loss in the dentate gyrus. In addition, lesioned APOE4 mice showed no evidence of reactional increase in cholinergic terminals density as opposed to APOE3 mice, suggesting that APOE4 interferes with the ability of the cholinergic system to respond to EC input loss. These findings provide a possible mechanism underlying the aggravating effect of APOE4 on the cognitive outcome of MCI patients.     

Efficacy of non-invasive brain stimulation on global cognition and neuropsychiatric symptoms in Alzheimer’s disease and mild cognitive impairment: A meta-analysis and systematic review

BackgroundNon-invasive brain stimulation (NIBS) techniques have shown some promise in improving cognitive and neuropsychiatric symptoms (NPS) in people with Alzheimer’s disease (AD) and its prodromal stage, mild cognitive impairment (MCI). However, data from clinical trials involving NIBS have shown inconsistent results. This meta-analysis investigated the efficacy of NIBS, specifically repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) compared to sham stimulation on global cognition and NPS in people with AD and MCI.MethodMulti-session randomized sham-controlled clinical trials were identified through MEDLINE, PsycINFO, and Embase until June 2021. Standardized mean difference (SMD) and 95% confidence interval (CI) between the active and sham treatments were calculated using random-effects meta-analyses. Included studies reported outcome measures for global cognition and/or NPS. Heterogeneity, from different NIBS techniques, disease populations, or tests used to assess global cognition or NPS, was measured using chi-square and I², and investigated using subgroup analyses. Possible effects of covariates were also investigated using meta-regressions.ResultThe pooled meta-analyses included 19 studies measuring global cognition (N_active=288, N_sham=264), and 9 studies investigating NPS (N_active=165, N_sham=140). NIBS significantly improved global cognition (SMD=1.14; 95% CI=0.49,1.78; p = 0.001; I² = 90.2%) and NPS (SMD=0.82; 95% CI=0.13, 1.50; p = 0.019; I² = 86.1%) relative to sham stimulation in patients with AD and MCI. Subgroup analyses found these effects were restricted to rTMS but not tDCS, and to patients with AD but not MCI. Meta-regression showed that age was significantly associated with global cognition response (N_studies=16, p = 0.020, I² = 89.51%, R² = 28.96%), with larger effects sizes in younger populations. All significant meta-analyses had large effect sizes (SMD ≥0.8), suggesting clinical utility of NIBS in the short term. There remained substantial heterogeneity across all subgroup analyses and meta-regressions (all I² > 50%). Egger’s tests showed no evidence of publication biases.ConclusionrTMS improved global cognition and NPS in those with AD. Further studies in MCI and using tDCS will help to fully evaluate the specific NIBS techniques and populations most likely to benefit on global cognition and NPS measures. Additional research should investigate the long term clinical utility of NIBS in these populations.     

Comparison of physiological response to cardiopulmonary exercise testing among cancer survivors and healthy controls

Selected physiological responses, including lactate kinetics, to cardiopulmonary exercise testing (CPET) were evaluated among a group of cancer survivors (CS, n = 55) and healthy controls (HC, n = 213). It was uncertain if lactate testing in a group of cancer survivors could provide useful information about training intensity. It was hypothesized that chemotherapy, radiation, surgery, physical inactivity or some combination thereof would alter the normal lactate kinetics (curvilinearity) in the relationship of lactate concentration versus power. Physiologic responses of CS (heart rate, blood pressure, O₂ saturation, RPE, lactate, VO_2peak, and peak power) during cycle ergometry were compared to HC. Comparisons (t tests and Chi-square) were made between the groups and shape of lactate plots were analyzed for determination of a breakpoint. Multiple logistical regressions were then utilized to identify factors related to the inability to determine lactate breakpoints. Lactate breakpoints were common to all but one HC whereas among the CS there was a small subset of subjects (n = 5) who did not show a lactate breakpoint. Group differences indicated that female CS were significantly older, had greater BMI’s, and lower work capacity than HC. Males CS had significantly lower work capacity than HC. Multiple logistical regression analyses, in all instances, yielded no statistically significant models predictive of the inability to determine a lactate breakpoint. In this sample of CS and HC, physiological responses and lactate kinetics during CPET were similar while work capacity among the CS was lower. Because lactate breakpoints were found, lactate threshold could be determined for all but a few individuals. For those working with CS, CPET with ECG monitoring and lactate threshold measures should be considered for those wishing for precise and safe training intensities.     

C9orf72 G4C2 repeat expansions in Alzheimer's disease and mild cognitive impairment

C9orf72 G₄C₂ repeat expansion is a major cause of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Its role in Alzheimer's disease (AD) is less clear. We assessed the prevalence of G₄C₂ pathogenic repeat expansions in Flanders-Belgian patients with clinical AD or mild cognitive impairment (MCI). In addition, we studied the effect of non-pathogenic G₄C₂ repeat length variability on susceptibility to AD, and on AD cerebrospinal fluid (CSF) biomarker levels. A pathogenic repeat expansion was identified in 5 of 1217 AD patients (frequency <1%). No pathogenic expansions were observed in patients with MCI (n = 200) or control individuals (n = 1119). Nonpathogenic repeat length variability was not associated with AD, risk of conversion to AD in MCI individuals, or CSF biomarker levels. We conclude that pathogenic C9orf72 G₄C₂ repeat expansions can be detected in clinical AD patients and could act as a contributor to AD pathogenesis. Non-pathogenic repeat length variability did not affect risk of AD or MCI, nor AD biomarker levels in CSF, indicating that C9orf72 is not a direct AD risk factor.     

Subjective cognitive decline predicts future deterioration in cognitively normal patients with Parkinson's disease

Increasing evidence suggests that subjective cognitive decline (SCD) is a potential predictor of future cognitive decline or dementia. We investigated whether SCD in patients with Parkinson's disease (PD) is a predictor of future cognitive decline. Forty-six cognitively normal patients with PD were selected using comprehensive neuropsychological tests, and classified depending on the presence (PD-SCD⁺, n = 25) or absence of SCD (PD-SCD⁻, n = 21). After a mean follow-up of 2.4 years, we repeated the cognitive assessments with the same subjects. The clinical characteristics and cognitive performance of the 2 groups did not differ at baseline. At the follow-up assessment, 11 patients in the PD-SCD⁺ group (44.0%) and 2 in the PD-SCD⁻ group (9.5%) were diagnosed with mild cognitive impairment (MCI), and the PD-SCD⁺ patients showed more rapid decline in semantic fluency and visuospatial memory tasks than those in the PD-SCD⁻ group. A multivariate logistic regression analysis showed that presence of SCD (odds ratio, 8.378; 95% confidential interval, 1.472–47.683, p = 0.017) and higher Unified PD Rating Scale motor score of 20 or more (odds ratio, 4.539; 95% confidential interval, 1.004–20.528; p = 0.049) were risk factors for incident MCI. Present results demonstrate that SCD in cognitively normal patients with PD is an independent risk factor for incident MCI and acts as a predictor for future cognitive decline.     

Utility of the RBANS in detecting cognitive impairment associated with Alzheimer's disease: Sensitivity, specificity, and positive and negative predictive powers

Although initially developed as a brief dementia battery, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has not yet demonstrated its sensitivity, specificity, and positive and negative predictive powers in detecting cognitive impairment in patients with Alzheimer's disease (AD). Therefore, the current study examined the clinical utility of the RBANS by comparing two age-, education-, and gender-matched groups: patients with AD (n = 69) and comparators (n = 69). Significant differences (p < 0.001) were observed on the RBANS Total score, all 5 Indexes, and all 12 subtests, with patients performing worse than the comparison participants. An optimal balance between sensitivity and specificity on RBANS scores was obtained when cutoffs of one and one and a half standard deviations below the mean of the comparison sample were implemented. Areas under the Receiver Operating Characteristic curves for all RBANS Indexes were impressive though Immediate and Delayed Memory Indexes were excellent (0.96 and 0.98, respectively). Results suggest that RBANS scores yield excellent estimates of diagnostic accuracy and that the RBANS is a useful screening tool in detection of cognitive deficits associated with AD.