Specificity Of Cognitive Impairment Research Articles

Screening for Cognitive Impairment with the Quick Memory Check: Validation of a Caregiver Administered Cognitive Screen.

Self or home-administered cognitive screening instruments (CSIs) can reduce barriers to the early detection of mild cognitive impairment (MCI) and dementia. To examine the acceptability and diagnostic accuracy of a caregiver-administered CSI, the Quick Memory Check (QMC). Components of the Quick Mild Cognitive impairment (Qmci) screen (orientation, verbal fluency, and logical memory) were re-weighted to create the QMC, scored out of 100 points. Participants, attending a university hospital memory clinic, were provided administration instructions beforehand. Area under the curve (AUC) scores, adjusted for age and education, were compared with the Qmci screen and Montreal Cognitive Assessment (MoCA). Caregivers or family scored the QMC. In all, 366 participants were recruited; 53 with subjective memory complaints (SMC), 74 with MCI, 193 with dementia, and 46 normal controls. Median QMC scores for controls were 70±13 versus 60±20 for SMC, 52±18 for MCI, and 31±21 for dementia. The QMC had excellent accuracy (AUC 0.97) for cognitive impairment (MCI/dementia from controls), similar to the Qmci screen (AUC 0.98, p = 0.17) and MoCA (AUC 0.95, p = 0.13). At a cut-off of <52/100, the QMC had 83% sensitivity and 100% specificity for cognitive impairment. The QMC had lower accuracy differentiating MCI from SMC (AUC 0.73), albeit similar to the MoCA (AUC 0.70). The QMC, administered by caregivers in advance of clinic, compared favorably to established CSIs scored by trained raters. This caregiver, home-administered CSI is acceptable and can identify cognitive impairment, potentially improving efficiency by reducing testing time and patient stress in busy clinical settings.

Potent protein biomarker for Alzheimer’s disease based on translational research

AbstractBackgroundAlzheimer's disease (AD) is an accelerating neurodegenerative disorder. Dysfunction of mitochondria and oxidative stress contributes to the pathogenesis of AD. Sirtuins play a role in this pathway and can be a potential marker to study neurodegenerative changesMethodThis study evaluated serum levels of all seven sirtuins (SIRT1 – SIRT7) proteins in three study groups: AD, Mild Cognitive Impairment (MCI), and Geriatric Control (GC) by Surface Plasmon Resonance (SPR) technique. Further, it was validated by the Western blot experiment. ROC analysis was performed to differentiate the study group based on the concentration of serum SIRT proteinsResultOut of seven sirtuins, serum SIRT1, SIRT3, and SIRT6 levels (mean+SD) were significantly decreased in AD (1.65±0.56, 3.15±0.28, 3.36±0.32ng/µl); compared to MCI (2.17±0.39, 3.60±0.51, 3.73±0.48ng/µl) and GC (2.84±0.47, 4.55±0.48, 4.65±0.55ng/µl). ROC analysis showed the cut‐off value with high sensitivity and specificity for cognitive impairment (AD and MCI). The concentration declined significantly with the disease progression. No specific difference was observed in case of other SIRTS between the study groups.ConclusionThis study reveals an inverse relation of serum SIRT1, SIRT3, and SIRT6 concentration with AD. ROC analysis showed that these serum proteins have greater accuracy in diagnosing of AD. This is the first report of estimation of all seven serum sirtuins and the clinical relevance of SIRT3 and SIRT6 as serum protein markers for AD.

Association of Anxiety and Depression with Objective and Subjective Cognitive Decline in Outpatient Healthcare Consumers with COVID-19: А Cross-Sectional Study.

In addition to the neurological complications affecting people infected with COVID-19, cognitive impairment symptoms and symptoms of anxiety and depression remain a frequent cause of complaints. The specificity of cognitive impairment in patients with COVID-19 is still poorly understood. An exploratory study of factors that may be associated with cognitive decline during the COVID-19 pandemic. The cross-sectional multicentre observational study was conducted in a polyclinic unit in Saint Petersburg and in the regions of the North-Western Federal Region. During the study, socio-demographic parameters and information about the somatic condition of patients who applied for primary health care was collected. Emotional and cognitive state were investigated using the Hospital Anxiety and Depression Scale (HADS) and Montreal Cognitive Assessment (MoCA). Mathematical and statistical data processing was carried out using SPSS and RStudio statistical programs. The study included 515 participants, 60% (n=310) of which were women. The sample was divided into those who did (28.5%, n=147) and did not (71.4%, n=368) complain of cognitive decline. Patients with complaints of cognitive decline were significantly older, had lower levels of education and higher levels of depression and anxiety according to HADS (p <0.05). Patients with complaints of cognitive decline underwent the MoCA test (24.3%, n=125). The median MoCA test scores were within the normal range (Median=27, Q1=25, Q3=28), and cognitive decline (MoCA less than 26 points) was detected in 40% (n=50) of patients with complaints of cognitive decline. No significant correlations were found between the MoCA scores and the levels of anxiety and depression according to the HADS (p >0.05). Patients with mild severity of the COVID-19 course were more successful with MoCA subtests than patients with moderate and severe courses. We found no linear association between objective cognitive deficit and the affective state of respondents. Patients' subjective complaints about cognitive dysfunction were mostly caused by their emotional state than an objective decrease of their cognitive functions. Therefore, in case of subjective complaints on cognitive decline, it is necessary to assess not only the cognitive but also the affective state of the patient. The severity of the COVID-19 course affects the functions of the cognitive sphere, including attention, regulatory functions and speech fluency. Mild and moderate severity of the COVID-19 correlates with clinically determined depression. The absence of this relationship with the severe course of the disease is probably explained by the significant somatic decompensation of patients.

Blood Circulatory Level of Seven Sirtuins in Alzheimer's Disease: Potent Biomarker Based on Translational Research.

Alzheimer's disease (AD) is an accelerating neurodegenerative disorder. Dysfunction of mitochondria and oxidative stress contributes to the pathogenesis of AD. Sirtuins play a role in this pathway and can be a potential marker to study neurodegenerative changes. This study evaluated serum levels of all seven sirtuin (SIRT1-SIRT7) proteins in three study groups: AD, mild cognitive impairment (MCI) and geriatric control (GC) by surface plasmon resonance (SPR) technique. Further, it was validated by the Western blot experiment. ROC analysis was performed to differentiate the study group based on the concentration of serum SIRT proteins. Out of seven sirtuins, serum SIRT1, SIRT3 and SIRT6 levels (mean ± SD) were significantly decreased in AD (1.65 ± 0.56, 3.15 ± 0.28, 3.36 ± 0.32ng/µl), compared to MCI (2.17 ± 0.39, 3.60 ± 0.51, 3.73 ± 0.48ng/µl) and GC (2.84 ± 0.47, 4.55 ± 0.48, 4.65 ± 0.55ng/µl). ROC analysis showed the cut-off value with high sensitivity and specificity for cognitive impairment (AD and MCI). The concentration declined significantly with the disease progression. No specific difference was observed in the case of other SIRTs between the study groups. This study reveals an inverse relation of serum SIRT1, SIRT3 and SIRT6 concentration with AD. ROC analysis showed that these serum proteins have greater accuracy in diagnosing of AD. This is the first report of estimation of all seven serum sirtuins and the clinical relevance of SIRT3 and SIRT6 as serum protein markers for AD.

Cognitive impairments in patients with overweight and obesity

Background. In modern society, the growth of the overweight and obese population increase every year. This confirms the status assigned to the problem under consideration as a non-infectious epidemic of the 21st century. At the same time, the amount of scientific information about the influence of excess weight on various aspects of human life is actively increasing. This undoubtedly requires a systematic generalization of the available data.Aims. The presented literature review is devoted to the analysis of modern scientific research on the specificity of cognitive impairment in overweight and obese people.Materials and methods. Information search was carried out using Internet resources (PubMed, Web of Science, eLibrary.ru, frontiersin.org, sciencedirect. com, ncbi.nlm.nih.gov), literature sources were analyzed for the period from 2001 to 2020 for the following keywords: obesity, overweight, cognitive functions, cognitions, cognitive impairments.Results. As a result of the literature review, the main directions of research on the relationship between cognitive impairment and overweight, as well as the relationship between cognitive dysfunction and obesity, were identified. The specificity of diametrically opposed opinions within the framework of each consecrated trend is presented. According to the results of the analysis of the identified areas, in the scientific community the most common point of view is the presence of a connection between obesity and cognitive impairment. In this connection, the authors identified the main cognitive impairments associated with excess weight and their mediating mechanisms. And also the age specificity of the problem under study is indicated.Conclusions. Despite the fact that the problem of the relationship between obesity, overweight and cognitive functions is comprehensively studied, there is a shortage of data on the state of thinking, attention, praxis, gnosis, and speech in overweight people.

Comparative sensitivity of the MoCA and Mattis Dementia Rating Scale‐2 in Parkinson's disease

Clinicians and researchers commonly use global cognitive assessments to screen for impairment. Currently there are no published studies directly comparing the sensitivity and specificity of the Montreal Cognitive Assessment and Mattis Dementia Rating Scale-2 in PD. The objective of this study was to identify the relative sensitivity and specificity of the Montreal Cognitive Assessment and Mattis Dementia Rating Scale-2 in PD. The Montreal Cognitive Assessment and Mattis Dementia Rating Scale-2 were administered to training and validation cohorts. Cutoff scores were determined within the training cohort (n = 85) to optimize sensitivity and specificity for cognitive impairment and were applied to an independent validation cohort (n = 521). The Montreal Cognitive Assessment was consistently sensitive across training and validation cohorts (90.0% and 80.3%, respectively), whereas the Mattis Dementia Rating Scale-2 was not (87.5% and 60.3%, respectively). In individual domains, the Montreal Cognitive Assessment remained sensitive to memory and visuospatial impairments (91.9% and 87.8%, respectively), whereas the Mattis Dementia Rating Scale-2 was sensitive to executive impairments (86.2%). The Montreal Cognitive Assessment and Mattis Dementia Rating Scale-2 demonstrated individual strengths. Future work should focus on developing domain-specific cognitive screening tools for PD. © 2018 International Parkinson and Movement Disorder Society.

Impairment of the еmotion control and social functioning in psychoses with depressive-paranoid symptoms

Background. The problem of social functioning is one of the most relevant at the present stage. Over the past decades, first being in the sphere of interests of social psychiatry it has become one of the main focuses of research in clinical psychiatry. The number of works on this topic is increasing and motivating researchers to look for predictors of violations in social functioning. Recently, a lot of attention in these studies is devoted to the study of social cognition. Though, the studies are carried out within the framework of individual nosology types. At the same time, in our opinion, it would be interesting to expand the study using the syndromological approach in the "broad field" of psychotic disorders.&#x0D; Aim. Study of social cognition in patients with depressive-paranoid symptoms in psychotic disorders with the following nosology types: paranoid schizophrenia (F 20.0), schizoaffective disorder, depressive type (F25.1) and recurrent depressive disorder, current episode severe with psychotic symptoms of inpatient treatment at the stage of remission.&#x0D; Materials and methods. 61 patients have been examined. They are divided into three groups according to nosology types: 1 group - 21 patients with a diagnosis of paranoid schizophrenia (F 20.0 - Sch), group 2 - 23 patients diagnosed with depressive type of schizoaffective disorder (F 25.1 - SchAD) ) and group 3 - 17 patients suffering from recurrent depressive disorder (F 33.3 - RDD). The evaluation of social cognition, namely the level of emotion management, was conducted using the Russian-language version of the test of J. Meier, P. Selovey and D. Caruso "Emotional Intelligence" (MSCEIT V. 2.0) in the adapted version of E.A. Sergienko, I.I. Vetrova [1] *. One of the four branches of the test was used, namely, "Emotion Management", as well as PANSS and PSP scales.&#x0D; Results. The MSCEIT test emotion control scales are within the normal range, but the ratios are different in three groups: in the group of patients with Sch (and is the highest among the three groups), the indicators of the regulation scale of their own emotional states in relation to the indicators of emotional regulation of the states of other people prevail. The opposite picture is observed in the group of patients with SchAD. At the same time, the group of patients with RDD has low rates on both scales, but they are close to the lower boundary of the norm. Consequently, at each of the nosology types there is a specificity of cognitive impairment caused by the major disease. It is also indicative that the clinical picture of schizophrenia and schizoaffective disorder is similar but opposite in terms of MSCEIT indicators. The revealed link of indicators of the function of managing emotions and the level of social functioning allows us to determine the "targets" for rehabilitation programs in Sch (regulation of emotional states of other people) and RDD (regulation of their own emotional states). However, in this study, no such "targets" have been detected in the SchAD. There has been detected no clear link between the level of social functioning and the severity of the negative (deficient) symptoms, which for a long time has been considered the main factor of social maladaptation, but our data require additional research and more observations.&#x0D; Conclusion. The connection of certain psychopathological symptoms with the indicators of emotional management function allows to determine the "risk groups" among patients with each of the nosology types, which in advance can direct psychotherapeutic or psycho-rehabilitation measures focused on the correction of detected cognitive impairments.

Специфика когнитивных нарушений у неврологических больных. Реабилитационные программы

Специфика когнитивных нарушений у неврологических больных. Реабилитационные программы

Training systems for correction of cognitive impairments in children and adolescents after antineoplastic therapy for malignant neoplasms of the central nervous system

Introduction. Previous research has documented the development of patients treated for malignant neoplasms (MN). Neurotoxicity of antineoplastic therapy leads to motor and cognitive impairments which affect memory and concentration. The present study attempts to test and evaluate the effectiveness of innovative methods of the correction of cognitive impairments using the Cognisens NeuroTracker training system.&#x0D; Materials and Methods. The study reviews (a) the methods of psychological testing of impairments, (b) the operating principle of training systems, (c) the options of training modes, and (d) clinical characteristics of the examined groups of patients. The pilot study involved 40 patients with the central nervous system (CNS) tumors at the age of 6–18 years. All the patients were treated in the Russkoe Pole (Russian Field) Rehabilitation Research Center of Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology, and Immunology of the Ministry of Health of the Russian Federation in 2016.&#x0D; Results. The study summarized the data obtained in psychological testing, the specificity of cognitive impairments, and the test of cognitive training systems in neurorehabilitation. The results of the complex clinical psychological diagnostics assessing cognitive and motor spheres determined the original status of patients. The present study assessed the validity and effectiveness of Cognisens NeuroTracker neurocognitive training system among patients with MN. The parameters of mental manipulation of visual and spatial images, solving problems of spatial orientation of moving objects, prediction and extrapolation have improved by the end of the training period consisted of 6 sessions. The results of memory and concentration training by the Cognisens NeuroTracker confirmed their effectiveness. These trainings improved the respondents’ effectiveness and success in these types of activity.&#x0D; Conclusion. The Cognisens NeuroTracker new cognitive training system was successfully approved. This new direction is perspective in the rehabilitation of patients treated for MN.&#x0D; Keywords: malignant neoplasms, neurotoxicity, children, cognitive disorders, psychological status, psychological testing, cognitive training systems, Cognisens NeuroTracker, rehabilitation

Bridging cognitive screening tests in neurologic disorders: A crosswalk between the short Montreal Cognitive Assessment and Mini-Mental State Examination

IntroductionTo provide a crosswalk between the recently proposed short Montreal Cognitive Assessment (s-MoCA) and Mini-Mental State Examination (MMSE) within a clinical cohort. MethodsA total of 791 participants, with and without neurologic conditions, received both the MMSE and the MoCA at the same visit. s-MoCA scores were calculated and equipercentile equating was used to create a crosswalk between the s-MoCA and MMSE. ResultsAs expected, s-MoCA scores were highly correlated (Pearson r = 0.82, P < .001) with MMSE scores. s-MoCA scores correctly classified 85% of healthy older adults and 91% of individuals with neurologic conditions that impair cognition. In addition, we provide an easy to use table that enables the conversion of s-MoCA score to MMSE score. DiscussionThe s-MoCA is quick to administer, provides high sensitivity and specificity for cognitive impairment, and now can be compared directly with the MMSE.

Assessing the performance of the four question abbreviated mental test in the acute geriatric setting

Background: Cognitive impairment is common amongst acute geriatric hospital admissions but detection is often poor and this is associated with worse outcomes. The four-question abbreviated mental test (AMT4) has previously been promoted nationally in the acute setting as a succinct assessment tool. However, a recent national dementia Commissioning for Quality and Innovation (CQUIN) goal recommends a single screening question followed by the tenquestion abbreviated mental test (AMT10). We aimed to evaluate the negative predictive value of the AMT4 within the acute setting by comparing it to three other validated tools. Methods: We identified 100 acute medical admissions (&gt;60 years old) with a negative AMT4 and administered the AMT10, six-item cognitive impairment test (6CIT) and confusion assessment method (CAM) within 24 hours of admission. Results: Forty-six percent of the participants scored positively on at least one of the additional tests despite a negative AMT4. Forty-four patients had a positive 6CIT, 23 had a positive AMT10 and six had a positive CAM. Using the 6CIT as a diagnostic standard, tests of short-term memory had the greatest sensitivity and specificity for cognitive impairment. Conclusions: Nearly half of the participants had signs of cognitive impairment despite a negative AMT4. Consequently, there is a risk of under diagnosis with potentially serious consequences for morbidity and mortality. Tests of shortterm memory were strongly associated with cognitive impairment. We propose the addition of such a test in order to increase the sensitivity of the AMT4 without compromising its brevity and utility in the acute setting.

Neuropsychological impairment in deficit vs. non-deficit schizophrenia

This study aimed to assess the severity and specificity of cognitive impairments that affect individuals with deficit versus non-deficit schizophrenia. We compared 26 patients with the deficit subtype of schizophrenia (SZ-D) and 79 with non-deficit schizophrenia (SZ-ND) to 316 healthy adults (NC). All study participants completed a battery with 19 individual cognitive measures. After adjusting their test performance for age, sex, race, education and estimated premorbid IQ, we derived regression-based T-scores for each measure and the six derived cognitive domains including attention, psychomotor speed, executive function, verbal fluency, visual memory, and verbal memory. Multivariate analyses of variance revealed significant group effects for every individual measure and domain of cognitive functioning (all ps < 0.001). Post hoc comparisons revealed that patients with SZ-D performed significantly worse than NCs in every cognitive domain. They also produced lower scores than the SZ-ND group in every domain, but only the difference for verbal fluency reached statistical significance. The correlations of the effect sizes shown by the SZ-D and SZ-ND patients were of intermediate magnitude for the individual tests ( r = 0.56, p < 0.01) and higher, but not statistically significant for the cognitive domains ( r = 0.79, p = 0.06). Patients with SZ-D demonstrate cognitive deficits that are both common and distinct from those shown by patients with SZ-ND. Their impairment of verbal fluency is consistent with the observation that poverty of speech is a clinically significant feature of patients with SZ-D.

Specificity of cognitive impairment from Pfiesteria piscicida exposure in rats : Attention and visual function versus behavioral plasticity

Pfiesteria piscicida is a toxic dinoflagellate that has caused massive fish kills in estuaries along the East Coast of the United States, and exposure of humans to toxic Pfiesteria has been associated with cognitive impairment. A visual signal detection task was used to determine the possible importance of attentional and visual processes in Pfiesteria effects on cognitive function. Adult female rats were trained to perform the signal detection task. After training, the rats were injected subcutaneously with fish culture water containing toxic Pfiesteria (35,600 or 106,800 cells of Pfiesteria/kg of rat body weight) or with (control) fish culture water containing no Pfiesteria. Effects of toxic Pfiesteria on maintenance of signal detection behavior were assessed for 2 weeks after treatment. Then, the signal-response contingencies were reversed. After the discrimination was reestablished on the reversed levers, the rats received a second dose of toxic Pfiesteria. The rats were again tested for 2 weeks, after which a second reversal was imposed. Pfiesteria did not affect behavior in the signal detection task during 2 weeks of prereversal testing after either exposure. However, a significant Pfiesteria-induced deficit emerged when the signal-response contingencies were reversed. These findings suggest that Pfiesteria-induced deficits emerge during periods of behavioral transition and not during performance of previously learned tasks.

The Construct Validity and Clinical Utility of the Frank Jones Story as a Brief Screening Measure of Cognitive Dysfunction

The use of quick and easily administered screening measures of cognitive functioning has become increasingly important in clinical settings. A number of brief screening instruments are available, but few have been thoroughly examined for their validity and clinical utility. The Frank Jones Story is a 2-minute screening procedure proposed to measure problem solving by asking patients to explain an absurd proposition. The authors used this screen to help them classify 155 patients as cognitively impaired or unimpaired based on a full neuropsychological evaluation. Overall, the total score on the Frank Jones Story was a good predictor of intact functioning for patients that were unimpaired but was poor at predicting cognitive dysfunction. However, various subscores of the test reflected differing patterns of sensitivity and specificity for cognitive impairment. These data suggest that the Frank Jones Story might have some utility for initial screening for cognitive dysfunction.

Contrasts between patients with affective disorders and patients with schizophrenia on a neuropsychological test battery.

This study was designed to ascertain the degree and specificity of cognitive impairments in patients with schizophrenia and patients with affective disorders. Cognitive function was assessed with a neuropsychological test battery in consecutively admitted patients with schizophrenia (N = 57), unipolar depression (N = 29), and bipolar disorder (N = 16). The performance of the schizophrenic group was significantly below that of the groups with affective disorders on measures of attention and psychomotor speed, verbal and visual memory, and problem solving and abstraction. IQ was lower in the schizophrenic group and appeared to have deteriorated from a normal premorbid level that was not different from that of the affective disorder groups, as determined by the Wide Range Achievement Test--Revised reading test, a putative measure of premorbid intelligence. When IQ was controlled, differences between the groups in problem solving and visual memory remained. Psychiatric symptoms had a larger impact on test performance in the affective disorder groups than in the schizophrenic group. These results suggest that patients with schizophrenia perform systematically worse on cognitive measures than patients with affective disorders, which is consistent with their generally poorer outcome. The results also indicate that schizophrenia and affective disorders are qualitatively distinguishable in neuropsychological terms, given differences in apparent intellectual deterioration, profiles of cognitive impairment, and associations between cognitive performance and psychopathology.

Dementia in Long-term Care Facilities: A Survey of the Ottawa-Carleton Region

RÉSUMÉUn recensement auprès de 26 établissements de soins prolongés de la Région d'Ottawa-Carleton, pour un total de 3825 bénéficiaires, a été fait afin d'évaluer la prévalence de démence ou de diminution des capacités cognitives dans la population visée. Les personnes présentant de la démence ou des problèmes de mémoire (selon les critères du DSM III) ont été identifiées par leurs infirmières. Un échantillon «stratifié» et aléatoire a été utilisé pour la validation des données. Les établissements de soins prolongés ont été «stratifies» selon le niveau des soins dispensés et leur grandeur. Onze établissements de chacune des trois strates ont été choisis aléatoirement. Ensuite, un échantillon aléatoire de 10 pour cent avec remplacement (411 bénéficiaires) a été déterminé. L'étude de validation s'est faite par: entrevues avec bénéficiaires utilisant deux instruments de dépistage; entrevues avec infirmières utilisant deux outils de fonctionnement et une révision des dossiers. Le recensement démontre une prévalence de 67 pour cent de problèmes cognitifs pour l'échantillon retenu, comparativement à 52 pour cent dans la population totale des bénéficiaires. La sensibilité du recensement pour la démence est de 95 pour cent et sa spécificité, 83 pour cent. Les résultats indiquent qu'un recensement entrepris par du personnel bien informé et directement impliqué avec les bénéficiaires, selon des definitions standardisées, est une méthode raisonnablement efficace d'estimer la prévalence de démence dans les établissements de soins prolongés.

Severity and Specificity of Cognitive Impairment in Alzheimer's, Huntington's, and Parkinson's Diseases and Progressive Supranuclear Palsy

To investigate differences in severity and specificity of cognitive impairment among various neurodegenerative diseases, we tested groups of patients presenting with senile dementia of the Alzheimer's type (SDAT) (n = 44), progressive supranuclear palsy (PSP) (n = 45), Huntington's disease (HD) (n = 35), and Parkinson's disease (PD) (n = 164), with an extensive neuropsychologic battery. We found dementia, as defined by a global intellectual performance 2 SD lower than mean control values, in 93% of patients with SDAT, 66% of patients with HD, 58% of patients with PSP, and 18% of patients with PD. Specific features of cognitive impairment distinguished the four groups of patients once they were matched for level of intellectual deterioration. This study shows the frequency of dementia in predominantly subcortical degenerative diseases and indicates that "subcortical dementia," rather than being a homogeneous entity, should be divided into specific subtypes of cognitive impairment related to different underlying pathology.

Severity and specificity of cognitive impairment in Alzheimer's, Huntington's, and Parkinson's diseases and progressive supranuclear palsy

To investigate differences in severity and specificity of cognitive impairment among various neurodegenerative diseases, we tested groups of patients presenting with senile dementia of the Alzheimer type (SDAT; 44), progressive supranuclear palsy (PSP; 45), Huntington's disease (HD; 35) and Parkinson's disease (PD; 164), with an extensive neuropsychological battery. We found dementia, as defined by a global intellectual performance 2 standard deviations lower than mean control values, in 93% of SDAT, 66% of HD, 58% of PSP, and 18% of PD patients. Specific features of cognitive impairment distinguished the four groups of patients once they were matched for level of intellectual deterioration: remote memory and linguistic disorders in SDAT, frontal lobe-like abnormalities in PSP, concentration and acquisition disorders in HD. There was no specific alteration in demented PD patients. This study demonstrates the frequency of dementia in predominantly subcortical degenerative diseases and indicates that "subcortical dementia," rather than being a homogeneous entity, should be divided into specific subtypes of cognitive impairment related to different underlying specific lesions of each disease.

Specificity of cognitive impairment in neurological disease: a methodological critique of Parkinson's disease.

Multiple cognitive deficits have been recognized in many neurological disorders but the specificity of the findings and the relationship to the underlying neuropathology remain obscure. Definitions of dementia have been proposed based on symptom profiles of the cognitive disorder and qualitative differences have been claimed between dementias of different aetiology. Some conditions have been claimed to show patterns of cognitive deficit that are distinguished from dementia and related to specific neuropathology or psychological processes, e.g. frontal lobe deficits in Parkinson's disease. Sometimes, a relationship has been established between certain cognitive deficits and particular neurochemical deficits which has led to the notion of specific drug treatment, e.g. cholinergic deficits and memory failure in Alzheimer's disease. However, these conclusions are often potentially flawed by methodological inadequacies. This critique presents some methodological issues relevant to the study of brain-behaviour and drug-behaviour relationships in syndromes of multiple cognitive deficit, using Parkinson's disease as the model. The following recommendations are made: rigid diagnostic criteria; representative patient groups; avoidance of arbitrary quantitative criteria to limit definitions of dementia; matching of groups for overall level of cognitive impairment in the search for qualitative cognitive differences related to neuropathology or effects of particular drugs; the use of suitable controls in patient groups, neuropsychological tests and treatment regimes; the use of specific quantitative tests of cognition, affect and motor disability; and longitudinal, compared with cross-sectional, study design.

Specificity of Cognitive Impairment in Neurological Disease: A Methodological Critique of Parkinson’s Disease

Multiple cognitive deficits have been recognized in many neurological disorders but the specificity of the findings and the relationship to the underlying neuropathology remain obscure. Definitions of dementia have been proposed based on symptom profiles of the cognitive disorder and qualitative differences have been claimed between dementias of different aetiology. Some conditions have been claimed to show patterns of cognitive deficit that are distinguished from dementia and related to specific neuropathology or psychological processes, e.g. frontal lobe deficits in Parkinson's disease. Sometimes, a relationship has been established between certain cognitive deficits and particular neurochemical deficits which has led to the notion of specific drug treatment, e.g. cholinergic deficits and memory failure in Alzheimer's disease. However, these conclusions are often potentially flawed by methodological inadequacies. This critique presents some methodological issues relevant to the study of brain-behaviour and drug-behaviour relationships in syndromes of multiple cognitive deficit, using Parkinson's disease as the model. The following recommendations are made: rigid diagnostic criteria; representative patient groups; avoidance of arbitrary quantitative criteria to limit definitions of dementia; matching of groups for overall level of cognitive impairment in the search for qualitative cognitive differences related to neuropathology or effects of particular drugs; the use of suitable controls in patient groups, neuropsychological tests and treatment regimes; the use of specific quantitative tests of cognition, affect and motor disability; and longitudinal, compared with cross-sectional, study design.