Predicting alcohol relapse post-detoxification: The role of cognitive impairments in alcohol use disorder patients.

BACKGROUND: Studies on early abstinence suggest that cognitive function is significantly reduced in the first year of abstinence, which raises the question of whether it is relevant to early relapse in patients with substance use disorders. This study investigates the extent to which impairments in executive function and memory predict alcohol relapse in patients with alcohol use disorder (AUD). Understanding these relationships is crucial for improving therapeutic approaches to prevent relapse in patients with AUD. METHODS: We selected 116 adult patients (79 male and 37 female) diagnosed with AUD based on DSM-5 criteria, all of whom were undergoing alcohol detoxification treatment. A comprehensive array of neuropsychological tests was administered to assess global cognition, memory, and executive functions. Patients' alcohol use was monitored monthly during a 6-month follow-up period. Logistic regression and Cox regression were used to explore the relationship between cognitive function and the likelihood of alcohol relapse. RESULTS: Impairments in global cognition, semantic and phonemic fluency, cognitive flexibility, and learning ability during detoxification were significant predictors of relapse in AUD patients, showing similar predictive values at both 3 and 6 months post-treatment. An abnormal Montreal Cognitive Assessment (MoCA) score increased the risk of relapse by 123% (HR: 2.227), and impairments in both semantic and phonemic fluency each increased the risk by 142% (HR: 2.423). Additionally, abnormal performance on the MoCA, Trail Making Test Part B (TMT-B), and California Verbal Learning Test (CVLT) was associated with a higher number of drinking days at 3 months (IRR: 3.764; IRR: 2.237; IRR: 2.738, respectively) and abnormal MoCA and TMT-B scores at 6 months (IRR: 2.451; IRR: 1.859, respectively). CONCLUSIONS: The MoCA test is a valuable tool for predicting relapse risk in AUD patients undergoing detoxification treatment, with similar predictive value for relapse at 3 or 6 months. Learning ability needs to be assessed and their impairments considered in the treatment of AUD patients. Future research should explore strategies for managing patients with impairments in memory and learning ability to enhance treatment effectiveness and prevent relapse.

Integrating Cognitive Factors and Eye Movement Data in Reading Predictive Models for Children with Dyslexia and ADHD-I.

This study reports on several specific neurocognitive processes and eye-tracking predictors of reading outcomes for a sample of children with Developmental Dyslexia (DD) and At-tention-Deficit/Hyperactivity Disorder - inattentive subtype (ADHD-I) compared to typical readers. Participants included 19 typical readers, 21 children diagnosed with ADHD-I and 19 children with DD. All participants were attending 4th grade and had a mean age of 9.08 years. The psycholinguistic profile of each group was assessed using a battery of neuropsy-chological and linguistic tests. Participants were submitted to a silent reading task with lex-ical manipulation of the text. Multinomial logistic regression was conducted to evaluate the predictive capability of developing dyslexia or ADHD-I based on the following measures: (a) a linguistic model that included measures of phonological awareness, rapid naming, and reading fluency and accuracy; (b) a cognitive neuropsychological model that included measures of memory, attention, visual processes, and cognitive or intellectual functioning, and (c) an additive model of lexical word properties with manipulation of word-frequency and word-length effects through eye-tracking. The additive model in conjunction with the neuropsychological model classification improved the prediction of who develops dyslexia or ADHD-I having as baseline normal readers. Several of the neuropsychological and eye-tracking variables have power to predict the degree of reading outcomes in children with learning disabilities.

Different MMSE domains are associated to cognitive decline and education.

The Mini-Mental State Examination (MMSE) is a long-established test to screen for dementia, estimate the severity and monitor the progression of cognitive impairment. The MMSE total score is dependent upon demographic factors, particularly education, but little is known about how education influences the 6 distinct MMSE cognitive domains. The present study aims to understand how the performances in the MMSE cognitive domains reflect clinical diagnosis and educational level. The study recruited 1043 participants, comprising 388 healthy controls, 360 patients with Mild Cognitive Impairment (MCI) and 295 patients with dementia. The association of the MMSE cognitive domains scores with clinical diagnosis (healthy, MCI, dementia) and educational level (primary education, middle school, high school and university/college) was analyzed with a multivariate ordinal regression model. The scores in all MMSE domains were generally higher in healthy controls as compared to patients with MCI, and higher in these as compared to patients with dementia. The MMSE domain Constructional ability was associated to the education level, the domains Orientation, Recall and Language were associated to diagnosis, Attention and calculation was associated to both education level and diagnosis, and Registration was not associated to either education or diagnosis. In conclusion, impairment in specific MMSE domains pinpoints cognitive decline, probably indicating brain areas affected by neurodegeneration, and impairment in others reflects lower education levels and the lack of acquisition of relevant schooling abilities.

Time perspective and amnestic mild cognitive impairment.

OBJECTIVE: We examined time perspective in patients with amnesic mild cognitive impairment (aMCI). Prior research has shown that aMCI is associated with difficulties in experiencing time duration and succession. However, this line of inquiry has not been extended to time perspective. We examined associations between aMCI and multiple dimensions of time perspective including perceived orientations and relationships among the past, present, and future. METHOD: Thirty aMCI patients and thirty-three healthy controls participated. Measures were the Time Orientation Scale (TOS), the Time Relation Scale (TRS), and the Zimbardo Time Perspective Inventory (ZTPI), as well as a comprehensive neuropsychological evaluation. RESULTS: The TRS was associated with aMCI. Patients with aMCI were more likely to perceive that time was unrelated than the healthy older adults. Among patients with aMCI, an unrelated time perspective was associated with poorer performance in executive function measures. However, aMCI was not associated with the TOS or the ZTPI. CONCLUSIONS: Patients with aMCI have difficulty in perceiving relationships among the past, present, and future. This could be the consequence of deficits in executive functions. This research suggests that patients with aMCI may have limited understanding for how their current behaviours are related to both their past and future.

The Outcome of Patients with Amyloid-Negative Amnestic Mild Cognitive Impairment.

BACKGROUND: Patients with amnestic mild cognitive impairment (aMCI) are usually at an initial stage of Alzheimer's disease (AD). However, some patients with aMCI do not present biomarkers of amyloid pathology characteristic of AD. The significance of amyloid-negative aMCI is not presently clear. OBJECTIVE: To know the etiology and prognosis of amyloid-negative aMCI. METHODS: Patients who fulfilled criteria for aMCI and were amyloid negative were selected from a large cohort of non-demented patients with cognitive complaints and were followed with clinical and neuropsychological assessments. RESULTS: Few amyloid-negative aMCI had evidence of neurodegeneration at the baseline, as reflected in cerebrospinal fluid elevated tau protein levels. About half of the patients remained essentially stable for long periods of time. Others manifested a psychiatric disorder that was not apparent at baseline, namely major depression or bipolar disorder. Remarkably, about a quarter of patients developed neurodegenerative disorders other than AD, mostly frontotemporal dementia or Lewy body disease. CONCLUSION: Amyloid-negative aMCI is a heterogeneous condition. Many patients remain clinically stable, but others may later manifest psychiatric conditions or evolve to neurodegenerative disorders. Prudence is needed when communicating to the patient and family the results of biomarkers, and clinical follow-up should be advised.

Effects of word length and word frequency among dyslexic, ADHD-I and typical readers.

This study aimed to investigate the neuropsycholinguistic functioning of children with Developmental Dyslexia (DD) and Attention-Deficit/Hyperactivity Disorder - inattentive subtype (ADHD-I) in a reading task. The psycholinguistic profile of both groups was assessed using a battery of neuropsychological and linguistic tests and compared to typical readers. Participants were submitted to a silent reading task with lexical manipulation of the text. Eye movements were recorded and compared aiming to find cognitive processes involved in reading that could help differentiate groups. The study examined whether word-frequency and word-length effects distinguish between groups. Participants included 19 typical readers, 21 children diagnosed with ADHD-I and 19 children with DD. All participants were attending 4th grade and had a mean age of 9.08 years. Children with DD and ADHDI exhibited significant different cognitive and linguistic profiles on almost all measures evaluated when compared to typical readers. The effects of word length and word frequency interaction also differed significantly in the 3 experimental groups. The results support the multiple cognitive deficits theory. While the shared deficits support the evidence of a phonological disorder present in both conditions, the specific ones corroborate the hypothesis of an oculomotor dysfunction in DD and a visuo-spatial attention dysfunction in ADHD.

Memory awareness in patients with Major Depressive Disorder.

BACKGROUND: Subjective Memory Complaints (SMC) along with cognitive deficits are frequently observed in patients with Major Depressive Disorder (MDD). The relationship between SMC and objective memory performance in patients with MDD was evaluated, in comparison with patients with Mild Cognitive Impairment due to Alzheimer's Disease (MCI-AD) and healthy controls (HC). METHODS: Patients with MDD (n = 47), MCI-AD (n = 43) and HC (n = 45) were assessed with a self-report memory complaints scale (SMCS) and underwent a comprehensive clinical and neuropsychological assessment. A discrepancy score between the Logical Memory delayed recall and the SMCS total score was calculated as a measure of memory awareness. RESULTS: Patients with MDD (12.5 ± 4.4) and patients with MCI-AD (10.9 ± 4.1) had not significantly different SMCS total scores, whereas HC showed significantly lower scores (4.0 ± 3.0). As much as 74.5% of patients with MDD patients and 65.1% of patients with MCI-AD reported prominent memory complaints, whereas only 4.4% of HC did. Patients with MDD had relatively preserved memory tests, resulting in a higher discrepancy score than both patients with MCI-AD and HC. The SMCS total score correlated positively with depressive symptoms in the 3 groups of participants. CONCLUSIONS: Patients with MDD showed inaccurate memory self-awareness as they under-estimated their memory functioning, a pattern distinct from both patients with MCI-AD and HC.

The update of semantic memories in amnestic mild cognitive impairment.

It is still controversial to what extent neocortical consolidated memories are susceptible of change by processes of reconsolidation and transformation throughout experience, and whether the medial temporal lobes are necessary for this update of semantic consolidated memories, as they are for episodic remembering. We hypothesize that patients with amnestic mild cognitive impairment (aMCI) who have deficits in episodic memory may also have difficulties in updating information on added new features of objects. Sixteen participants with aMCI and 20 healthy control participants performed a semantic word-to-picture task, in which they were asked to identify as belonging to a given semantic category NEW objects, that have incorporated novel features, as well as OLD items, semantically and visually SIMILAR items and UNRELATED items. Patients with aMCI made a greater percentage of errors than healthy controls. Participants globally made greater percentages of errors in difficult types of items, namely NEW and SIMILAR, as compared to easier ones, OLD and UNRELATED. Importantly, an item by diagnostic group interaction effect was observed, and post hoc analysis showed that patients with aMCI made a higher percentage of errors than controls in NEW items only. In conclusion, patients with aMCI had a particular difficulty in identifying the NEW items of the word-to-picture task as compared to the control participants, supporting the concept of a flexible and dynamic conceptual knowledge system, involving the update of semantic memories and the integration of new attributes in a constant transformation process, which is impaired in these patients.

Neuropsychological profile of amyloid-positive versus amyloid-negative amnestic Mild Cognitive Impairment.

INTRODUCTION: Patients diagnosed with amnestic mild cognitive impairment (aMCI) are at high risk of progressing to dementia. It became possible, through the use of biomarkers, to diagnose those patients with aMCI who have Alzheimer's disease. However, it is presently unfeasible that all patients undergo biomarker testing. Since neuropsychological testing is required to make a formal diagnosis of aMCI, it would be interesting if it could be used to predict the amyloid status of patients with aMCI. METHODS: Participants with aMCI, known amyloid status (Aß+ or Aß-) and a comprehensive neuropsychological evaluation, were selected from the Cognitive Complaints Cohort database for this study. Neuropsychological tests were compared in Aß+ and Aß- aMCI patients. A binary logistic regression analysis was conducted to model the probability of being amyloid positive. RESULTS: Of the 216 aMCI patients studied, 117 were Aß+ and 99 were Aß-. Aß+ aMCI patients performed worse on several memory tests, namely Word Total Recall, Logical Memory Immediate and Delayed Free Recall, and Verbal Paired Associate Learning, as well as on Trail Making Test B, an executive function test. In a binary logistic regression model, only Logical Memory Delayed Free Recall retained significance, so that for each additional score point in this test, the probability of being amyloid positive decreased by 30.6%. The resulting model correctly classified 64.6% of the aMCI cases regarding their amyloid status. CONCLUSIONS: The neuropsychological assessment remains an essential step to diagnose and characterize patients with aMCI; however, neuropsychological tests have limited value to distinguish the aMCI patients who have amyloid pathology from those who might suffer from other clinical conditions.

Impact of dementia on informal care: a systematic review of family caregivers' perceptions.

INTRODUCTION: Caregivers play a major role in providing all the support and care in daily activities for their relatives with dementia. To fully describe the influence of dementia caregiving on family caregivers' life, we conducted a systematic review including caregivers' perceptions about the positive and negative aspects of caring and the expressed factors. MATERIALS AND METHODS: We conducted a systematic review including articles from January 1998 to July 2020. Qualitative studies reporting family caregivers' perceptions about their experiences and the effects/impact of dementia caregiving were eligible. Two authors extracted the data independently, and the analysis focused on the positive and negative aspects of dementia caregiving in caregivers' life. RESULTS: Eighty-one studies with 3347 participants were included in this review. The positive aspects of caregiving in caregivers' life encompass personal accomplishment and strengthening relationships, which were enhanced by good medical counselling/formal care support and family/friends support. The negative aspects included emotional and social aspects experienced by caregivers. Other factors such as inappropriate medical/formal care support, illness progression and the costs of dementia contributed to negative appraisal. DISCUSSION AND IMPLICATIONS: The findings provide insights into the holistic experience of caring for a person with dementia revelling the major positive and negative aspects underlying the caregiver role. The evidence emphasises the need 'to focus on positive aspects' and targeted interventions aimed at reducing the negative impact of caregiving, which has serious consequences on caregivers' quality of life. A multicomplex intervention for dementia informal caregiving should be developed, committing the society to promote mental health, address these community needs and improve the quality of life of the person with dementia and their family caregivers.

Neuropsychological Contribution to Predict Conversion to Dementia in Patients with Mild Cognitive Impairment Due to Alzheimer's Disease.

BACKGROUND: Diagnosis of Alzheimer's disease (AD) confirmed by biomarkers allows the patient to make important life decisions. However, doubt about the fleetness of symptoms progression and future cognitive decline remains. Neuropsychological measures were extensively studied in prediction of time to conversion to dementia for mild cognitive impairment (MCI) patients in the absence of biomarker information. Similar neuropsychological measures might also be useful to predict the progression to dementia in patients with MCI due to AD. OBJECTIVE: To study the contribution of neuropsychological measures to predict time to conversion to dementia in patients with MCI due to AD. METHODS: Patients with MCI due to AD were enrolled from a clinical cohort and the effect of neuropsychological performance on time to conversion to dementia was analyzed. RESULTS: At baseline, converters scored lower than non-converters at measures of verbal initiative, non-verbal reasoning, and episodic memory. The test of non-verbal reasoning was the only statistically significant predictor in a multivariate Cox regression model. A decrease of one standard deviation was associated with 29% of increase in the risk of conversion to dementia. Approximately 50% of patients with more than one standard deviation below the mean in the z score of that test had converted to dementia after 3 years of follow-up. CONCLUSION: In MCI due to AD, lower performance in a test of non-verbal reasoning was associated with time to conversion to dementia. This test, that reveals little decline in the earlier phases of AD, appears to convey important information concerning conversion to dementia.

Targeting the uncertainty of predictions at patient-level using an ensemble of classifiers coupled with calibration methods, Venn-ABERS, and Conformal Predictors: A case study in AD.

Despite being able to make accurate predictions, most existing prognostic models lack a proper indication about the uncertainty of each prediction, that is, the risk of prediction error for individual patients. This hampers their translation to primary care settings through decision support systems. To address this problem, we studied different methods for transforming classifiers into probabilistic/confidence-based predictors (here called uncertainty methods), where predictions are complemented with probability estimates/confidence regions reflecting their uncertainty (uncertainty estimates). We tested several uncertainty methods: two well-known calibration methods (Platt Scaling and Isotonic Regression), Conformal Predictors, and Venn-ABERS predictors. We evaluated whether these methods produce valid predictions, where uncertainty estimates reflect the ground truth probabilities. Furthermore, we assessed the proportion of valid predictions made at high-certainty thresholds (predictions with uncertainty measures above a given threshold) since this impacts their usefulness in clinical decisions. Finally, we proposed an ensemble-based approach where predictions from multiple pairs of (classifier, uncertainty method) are combined to predict whether a given MCI patient will convert to AD. This ensemble should putatively provide predictions for a larger number of patients while releasing users from deciding which pair of (classifier, uncertainty method) is more appropriate for data under study. The analysis was performed with a Portuguese cohort (CCC) of around 400 patients and validated in the publicly available ADNI cohort. Despite our focus on MCI to AD prognosis, the proposed approach can be applied to other diseases and prognostic problems.

Can Subjective Memory Complaints Identify Aß Positive and Aß Negative Amnestic Mild Cognitive Impairment Patients?

BACKGROUND: The use of biomarkers, in particular amyloid-ß (Aß) changes, has allowed the possibility to identify patients with subjective memory complaints (SMCs) and amnestic mild cognitive impairment (aMCI) who suffer from Alzheimer's disease (AD). Since it is unfeasible that all patients with aMCI could presently undergo biomarkers assessment, it would be important that SMCs might contribute to identify the aMCI patients who have AD amyloid pathology. OBJECTIVES: To know whether aMCI patients with amyloid biomarkers (Aß+) present greater SMCs as compared to those without amyloid biomarkers (Aß-). METHODS: Participants were selected from a cohort of nondemented patients with cognitive complaints and a comprehensive neuropsychological evaluation, on the basis of 1) diagnosis of aMCI; 2) detailed assessment of memory difficulties with the SMC Scale; and 3) known amyloid status. The amyloid status was determined on the basis of either CSF Aß1-42 concentration or amyloid PET imaging. RESULTS: Of the 176 patients with aMCI studied, 90 were Aß+ and 86 were Aß-. The two groups did not differ in terms of age, gender, and education. The SMC total score was not significantly different in the Aß+ aMCI patients (9.48±4.18) when compared to the Aß- aMCI patients (10.52±4.57). The Aß+ aMCI patients had lower scores on the MMSE and memory/learning tests, but not on the Geriatric Depression Scale, when comparing to the Aß- aMCI patients. CONCLUSIONS: Evaluating SMCs does not seem helpful to identify, among patients with aMCI, those who have AD.

Mental time travel in mild cognitive impairment.

Introduction: Mental Time Travel (MTT) is the people's ability to remember themselves in the past and to imagine themselves in the future, and influence important life domains such as making decisions and planning future actions. It is widely recognized that patients with aMCI have deficits in episodic memory, but they also show impairments in semantic memory. It has been controversial whether MTT tasks are disturbed in aMCI mainly in relation to internal details related to episodic information, or external details, representing semantic and other extraneous information. The present study assessed whether patients with aMCI are affected in MTT regarding generation of internal details and external details, in past and future dimensions. Furthermore, it analyzed production in individual detail categories (internal: event details, thought/emotion, place, time, perceptual; external: extraneous events, semantic, other, repetitions). Method: Twenty-nine patients with aMCI and 29 healthy controls underwent a MTT task based on an Autobiographical Interview, where they had to generate past and future events in response to cue words. Transcriptions were segmented and classified into internal detail categories and external detail categories, and composite scores were obtained. Results: Patients with aMCI could globally produce significantly less details than controls. Similar to controls, patients with aMCI produced more internal details than external details, had more difficulty in generating details regarding the future as compared to the past, and scored higher in the detail categories event details and thought/emotion which represent internal detail types. Conclusions: Patients with aMCI showed widespread deficits in MTT, presumably reflecting deficiencies in the complex and multiple cognitive abilities required for MTT tasks.

Neuropsychological predictors of conversion from mild cognitive impairment to Alzheimer's disease: a feature selection ensemble combining stability and predictability.

BACKGROUND: Predicting progression from Mild Cognitive Impairment (MCI) to Alzheimer's Disease (AD) is an utmost open issue in AD-related research. Neuropsychological assessment has proven to be useful in identifying MCI patients who are likely to convert to dementia. However, the large battery of neuropsychological tests (NPTs) performed in clinical practice and the limited number of training examples are challenge to machine learning when learning prognostic models. In this context, it is paramount to pursue approaches that effectively seek for reduced sets of relevant features. Subsets of NPTs from which prognostic models can be learnt should not only be good predictors, but also stable, promoting generalizable and explainable models. METHODS: We propose a feature selection (FS) ensemble combining stability and predictability to choose the most relevant NPTs for prognostic prediction in AD. First, we combine the outcome of multiple (filter and embedded) FS methods. Then, we use a wrapper-based approach optimizing both stability and predictability to compute the number of selected features. We use two large prospective studies (ADNI and the Portuguese Cognitive Complaints Cohort, CCC) to evaluate the approach and assess the predictive value of a large number of NPTs. RESULTS: The best subsets of features include approximately 30 and 20 (from the original 79 and 40) features, for ADNI and CCC data, respectively, yielding stability above 0.89 and 0.95, and AUC above 0.87 and 0.82. Most NPTs learnt using the proposed feature selection ensemble have been identified in the literature as strong predictors of conversion from MCI to AD. CONCLUSIONS: The FS ensemble approach was able to 1) identify subsets of stable and relevant predictors from a consensus of multiple FS methods using baseline NPTs and 2) learn reliable prognostic models of conversion from MCI to AD using these subsets of features. The machine learning models learnt from these features outperformed the models trained without FS and achieved competitive results when compared to commonly used FS algorithms. Furthermore, the selected features are derived from a consensus of methods thus being more robust, while releasing users from choosing the most appropriate FS method to be used in their classification task.

Memory complaints in amnestic Mild Cognitive Impairment: More prospective or retrospective?

OBJECTIVE: Patients with amnestic Mild Cognitive Impairment (aMCI), usually considered an early stage of Alzheimer's disease, have deficits not only in retrospective memory (RM), that is, recalling of past events, words or people, but also on prospective memory (PM), the cognitive ability of remembering to execute delayed intentions in the future. This study investigated whether patients with aMCI refer more PM complaints as compared with RM complaints, and whether this might depend upon short-term vs long-term items or time-based vs event-based tasks. METHODS: Patients with aMCI (n = 178) and healthy controls (n = 160) underwent the Prospective and Retrospective Memory Questionnaire (PRMQ), a 16-item instrument to appraise differences between PM and RM complaints, as well as a general mental state examination, a subjective memory complaints questionnaire, objective memory tests, and assessment of depressive symptoms and activities of daily living. RESULTS: Patients with aMCI reported more memory complaints evaluated with the PRMQ (total score = 44.3 ± 10.8) as compared with controls (36.7 ± 9.8, P < 0.001). Using a mixed effect repeated-measures analysis of covariance (ANCOVA) showed that participants generally referred more retrospective than prospective memory complaints. Patients with aMCI had significantly more complaints on short-term memory as compared with long-term memory, and more complaints in time-based (auto-initiated) as compared with event-based tasks, than healthy controls. CONCLUSION: Patients with aMCI reported significantly more difficulties on short-term memory, presumably reflecting internal temporal lobe pathology typical of Alzheimer's disease, and more complaints on time-based tasks, which are cognitively very demanding, but did not seem particularly troubled regarding prospective memory.

Neuropsychological Predictors of Long-Term (10 Years) Mild Cognitive Impairment Stability.

BACKGROUND: Although the diagnosis of mild cognitive impairment (MCI) corresponds to a condition likely to progress to dementia, essentially Alzheimer's disease, longitudinal studies have shown that some patients may not convert to dementia and maintain the diagnosis of MCI even after many years. OBJECTIVES: To determine whether patients that maintain the diagnosis of MCI in the long term (10 years) are really stable or just declining slowly, and to identify clinical and neuropsychological characteristics associated with long-term stability. METHODS: The Cognitive Complaints Cohort (CCC) was searched for MCI cases who maintained that diagnosis for at least 10 years. For each long-term-stable MCI patient, two MCI patients that converted to dementia during follow-up, matched for age and education, were selected from the same database. The baseline and last neuropsychological evaluations for long-term-stable MCI and converter MCI were compared. Baseline neuropsychological predictors of long-term stability were searched for. RESULTS: Long-term-stable MCI (n = 22) and converter MCI (n = 44) patients did not differ in terms of gender distribution, education, age at first assessment and time between symptom onset and first evaluation. Time of follow-up was on average 11 years for long-term-stable MCI and 3 years for converter MCI. The baseline and follow-up neuropsychological tests were not significantly different in long-term-stable MCI patients, whereas a general decline was observed in converter MCI patients. Higher scores on one memory test, the Word Delayed Total Recall, and on the non-verbal abstraction test, Raven's Progressive Matrices, at the baseline predicted long-term (10 years) clinical stability. CONCLUSIONS: Some patients with MCI remain clinically and neuropsychologically stable for a decade. Better performances at baseline in memory and non-verbal abstraction tests predict long-term stability.

Alzheimer's Disease Assessment Scale - Cognitive Subscale (ADAS-Cog): Normative Data for the Portuguese Population.

INTRODUCTION: The Alzheimer's Disease Assessment Scale - Cognitive Subscale is a brief battery developed to assess cognitive functioning in Alzheimer's disease that encompasses the core characteristics of cognitive decline (e.g. memory, language, praxis, constructive ability and orientation). The early detection, as well as the monitoring of cognitive decline along disease progression, is extremely important in clinical care and interventional research. The main goals of the present study were to analyze the psychometric properties of the Portuguese version of the Alzheimer's Disease Assessment Scale - Cognitive Subscale, and to establish normative values for the Portuguese population. MATERIAL AND METHODS: The Portuguese version of Alzheimer's Disease Assessment Scale - Cognitive Subscale was administered to 223 cognitively healthy participants according to a standard assessment protocol consisting of the Mini-Mental State Examination, the Montreal Cognitive Assessment and the Adults and Older Adults Functional Assessment Inventory. Normal performance on the assessment protocol was the inclusion criteria for the study. RESULTS: The Alzheimer's Disease Assessment Scale - Cognitive Subscale revealed good psychometric properties when used in the Portuguese population. Age was the main predictor of the Alzheimer's Disease Assessment Scale - Cognitive Subscale total score (R2 = 0.123), whereas the influence of education level was lower (R2 = 0.027). These two variables explained 14.4% of the variance on the Alzheimer's Disease Assessment Scale - Cognitive Subscale scores and were used to stratify the normative values for the Portuguese population presented here. CONCLUSION: On the total sample, the average total score in the Alzheimer's Disease Assessment Scale - Cognitive Subscale was 6 points. The normative data were determined according to age and educational level as these were the sociodemographic variables that significantly contributed to the prediction of the Alzheimer's Disease Assessment Scale - Cognitive Subscale total scores, explaining 14.4% of their variance. The normative data are of the utmost importance to ensure proper use of this battery in Portugal.

Introdução: A Escala de Avaliação da Doença de Alzheimer ­ subescala cognitiva (ADAS-Cog) é uma bateria neuropsicológica breve desenvolvida para caracterizar o desempenho cognitivo de doentes com doença de Alzheimer. Avalia as funções tipicamente mais comprometidas na doença de Alzheimer considerando os seguintes domínios cognitivos: memória, orientação, linguagem, praxia e capacidade construtiva. A deteção precoce das alterações cognitivas assim como a sua monitorização são fundamentais para a prática em ambos os contextos clínico e de investigação. O presente estudo tem como objetivos analisar as propriedades psicométricas da versão portuguesa da Escala de Avaliação da Doença de Alzheimer ­ subescala cognitiva e estabelecer dados normativos para a população portuguesa. Material e Métodos: A versão portuguesa da Escala de Avaliação da Doença de Alzheimer ­ subescala foi administrada a 223 participantes cognitivamente saudáveis. Todos os participantes foram avaliados com os seguintes instrumentos: Mini-Mental State Examination, Montreal Cognitive Assessment e Inventário de Avaliação Funcional de Adultos e Idosos. Considerou-se como critério para a inclusão no estudo obter um desempenho normal nestas três provas.Resultados: A Escala de Avaliação da Doença de Alzheimer ­ subescala revelou boas propriedades psicométricas quando utilizada na população portuguesa. A idade demonstrou ser o principal preditor do desempenho na Escala de Avaliação da Doença de Alzheimer ­ subescala (R2 = 0,123), tendo a escolaridade menor influência (R2 = 0,027). Em conjunto, estas variáveis sociodemográficas explicaram 14,4% da variância na pontuação total da Escala de Avaliação da Doença de Alzheimer ­ subescala, sendo ambas consideradas na estratificação dos dados normativos para a população portuguesa. Conclusão: A pontuação total média na Escala de Avaliação da Doença de Alzheimer ­ subescala foi de 6 pontos. Os dados normativos foram estabelecidos de acordo com a idade e escolaridade, sendo estas variáveis sociodemográficas as que mais contribuíram para a predição do desempenho na Escala de Avaliação da Doença de Alzheimer ­ subescala, explicando 14,4% da variância. Os dados normativos são de extrema importância para o uso adequado desta bateria em Portugal.

Predicting progression of mild cognitive impairment to dementia using neuropsychological data: a supervised learning approach using time windows.

BACKGROUND: Predicting progression from a stage of Mild Cognitive Impairment to dementia is a major pursuit in current research. It is broadly accepted that cognition declines with a continuum between MCI and dementia. As such, cohorts of MCI patients are usually heterogeneous, containing patients at different stages of the neurodegenerative process. This hampers the prognostic task. Nevertheless, when learning prognostic models, most studies use the entire cohort of MCI patients regardless of their disease stages. In this paper, we propose a Time Windows approach to predict conversion to dementia, learning with patients stratified using time windows, thus fine-tuning the prognosis regarding the time to conversion. METHODS: In the proposed Time Windows approach, we grouped patients based on the clinical information of whether they converted (converter MCI) or remained MCI (stable MCI) within a specific time window. We tested time windows of 2, 3, 4 and 5 years. We developed a prognostic model for each time window using clinical and neuropsychological data and compared this approach with the commonly used in the literature, where all patients are used to learn the models, named as First Last approach. This enables to move from the traditional question "Will a MCI patient convert to dementia somewhere in the future" to the question "Will a MCI patient convert to dementia in a specific time window". RESULTS: The proposed Time Windows approach outperformed the First Last approach. The results showed that we can predict conversion to dementia as early as 5 years before the event with an AUC of 0.88 in the cross-validation set and 0.76 in an independent validation set. CONCLUSIONS: Prognostic models using time windows have higher performance when predicting progression from MCI to dementia, when compared to the prognostic approach commonly used in the literature. Furthermore, the proposed Time Windows approach is more relevant from a clinical point of view, predicting conversion within a temporal interval rather than sometime in the future and allowing clinicians to timely adjust treatments and clinical appointments.