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Since Alzheimer's disease may affect driving performance, patients with Alzheimer's disease are assessed on fitness to drive. On-road driving assessments are widely used, and attempts have also been made to develop strategies to assess fitness to drive in a clinical setting. Preferably, a first indication of fitness to drive is obtained quickly after diagnosis using a single test such as the Mini-Mental State Examination (MMSE). The aim of this study is to investigate whether the MMSE can be used to predict whether patients with Alzheimer's disease will pass or fail an on-road driving assessment. Patients with Alzheimer's disease (n = 81) participated in a comprehensive fitness-to-drive assessment which included the MMSE as well as an on-road driving assessment [PLoS One 11(2):e0149566, 2016]. MMSE cutoffs were applied as suggested by Versijpt and colleagues [Acta Neurol Belg 117(4):811-819, 2017]. All patients with Alzheimer's disease who scored below the lower cutoff (MMSE ≤ 19) failed the on-road driving assessment. However, a third of the patients with Alzheimer's disease who scored above the upper cutoff (MMSE ≥ 25) failed the on-road driving assessment as well. We conclude that the MMSE alone has insufficient predictive value to correctly identify fitness to drive in patients with very mild-to-mild Alzheimer's disease implicating the need for comprehensive assessments to determine fitness to drive in a clinical setting.
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Doença de Alzheimer/psicologia , Condução de Veículo/psicologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Feminino , Humanos , Masculino , Testes de Estado Mental e Demência , Pessoa de Meia-Idade , Índice de Gravidade de DoençaRESUMO
Neglect patients typically fail to explore the contralesional half-space. During visual scanning training, these patients learn to consciously pay attention to contralesional target stimuli. It has been suggested that combining scanning training with methods addressing non-spatial attention might enhance training results. In the present study, a dual task training component was added to a visual scanning training (i.e., Training di Scanning Visuospaziale - TSVS; Pizzamiglio et al., 1990). Twenty-nine subacute right hemisphere stroke patients were semi-randomly assigned to an experimental (N = 14) or a control group (N = 15). Patients received 30 training sessions during 6 weeks. TSVS consisted of four standardized tasks (digit detection, reading/copying, copying drawings, and figure description). Moreover, a driving simulator task was integrated in the training procedure. Control patients practiced a single lane tracking task for 2 days a week during 6 weeks. The experimental group was administered the same training schedule, but in weeks 4-6 of the training, the TSVS digit detection task was combined with lane tracking on the same projection screen, so as to create a dual task (computerized visual reaction time task designed for training). Various neglect tests and driving simulator tasks were administered before and after training. No significant group and interaction effects were found that might reflect additional positive effects of dual task training. Significant improvements after training were observed in both groups taken together on most assessment tasks. Ameliorations were generally not correlated to post-onset time, but spontaneous recovery, test-retest variability, and learning effects could not be ruled out completely, since these were not controlled for. Future research might focus on increasing the amount of dual task training, the implementation of progressive difficulty levels in driving simulator tasks, and further exploration of relationships between dual task training and daily functioning.
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It has been hypothesized that cerebral lateralization of function enhances cognitive performance. Evidence was found in birds and fish. However, recent research in humans did not support this hypothesis. We aimed to replicate and extend these findings for single- and dual-task performance in an ecologically relevant task. We combined a word generation task which is assumed to be primarily processed in the left hemisphere with a driving task which is assumed to be primarily processed in the right hemisphere. For each task the individual strength and direction of hemispheric lateralization was assessed by using functional transcranial Doppler sonography (fTCD). For each subject (36 right-handed, 35 nonright-handed) performance was measured in the two single-tasks and in the dual-task condition. On average, subjects showed a left hemisphere bias for the word generation task, a right hemisphere bias for the driving task and dual-task interference. Within subjects, lateralization of language and driving were statistically independent. In accordance with earlier studies, the results show no indication of a positive effect of strength of lateralization on performance in single-tasks or dual-task efficiency. We also found no advantage of a typical compared to an atypical or a contralateral compared to an ipsilateral lateralization pattern. In right-handers, but not in nonright-handers, we even found a negative relationship between strength of lateralization and dual-task efficiency for atypically lateralized subjects. This further supports the suggestion that lateralization does not enhance cognitive performance in humans.
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Atenção/fisiologia , Condução de Veículo/psicologia , Lateralidade Funcional/fisiologia , Desempenho Psicomotor/fisiologia , Comportamento Verbal/fisiologia , Mapeamento Encefálico , Feminino , Humanos , Masculino , Mascaramento Perceptivo , Resolução de Problemas/fisiologia , Valores de Referência , Ultrassonografia Doppler Transcraniana , Adulto JovemRESUMO
BACKGROUND AND AIMS: Many people with schizophrenia have severe cognitive impairments that hamper their activities. The effect of pharmacological and behavioural interventions on cognitive functioning has been demonstrated, but even after successful intervention considerable impairments can remain. Therefore, we sought for alternative ways to help patients cope with the effects of their cognitive impairments. In the present study, we have evaluated the efficacy of short message service (SMS) text messages to compensate for the effects of cognitive impairments in schizophrenia in daily life. DESIGN: A waiting list controlled trial was conducted: patients were quasi-randomly assigned to an A-B-A (baseline-intervention-follow-up) condition or an A-A-B-A condition that included an additional 7-week waiting list. The waiting list was included to control for the effect of time on relevant outcome. METHOD: Sixty-two people with schizophrenia or related psychotic disorders were included in the study. All patients showed impaired goal-directed behaviour in daily life-situations. Patients were prompted with SMS text messages to improve their everyday functioning. The primary outcome measure was the percentage of goals achieved. RESULTS: The overall percentage of goals achieved increased with prompting, while performance dropped to baseline level after withdrawing the prompts. Keeping appointments with mental health workers and carrying out leisure activities increased with prompting, while medication adherence and attendance at training sessions remained unchanged. A majority of the patients enjoyed receiving the SMS text messages. DISCUSSION: Prompting can significantly improve achievement of a number of relevant goals. For other goals, combining prompting with interventions that enhance motivation seems indicated.
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Transtornos Cognitivos/epidemiologia , Transtornos Cognitivos/terapia , Comunicação , Internet/instrumentação , Esquizofrenia/epidemiologia , Adulto , Antipsicóticos/uso terapêutico , Feminino , Humanos , Masculino , Motivação , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Esquizofrenia/tratamento farmacológico , Autoimagem , Comportamento Social , Inquéritos e Questionários , Listas de EsperaRESUMO
The objective of this study was to examine the unique contribution of social cognition to the prediction of community functioning and to explore the relevance of social cognition for clinical practice. Forty-six schizophrenia patients and 53 healthy controls were assessed with tests of social cognition [emotion perception and Theory of Mind (ToM)], general cognition, and, within the patient sample, psychiatric symptoms. Community functioning was rated by nurses or family members. Social cognition was a better predictor of community functioning than general cognition or psychiatric symptoms. When the contributions of emotion perception and ToM were examined separately, only ToM contributed significantly to the prediction of community functioning. Independent living skills were poor in patients with impaired social cognition. In controls, social cognition was not related to community functioning. ToM was the best predictor of community functioning in schizophrenia. However, to fully understand a patient's strengths and weaknesses, assessment of social cognition should always be combined with assessment of general cognition and psychiatric symptoms.
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Transtornos Cognitivos/etiologia , Características de Residência , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Comportamento Social , Percepção Social , Adulto , Feminino , Humanos , Relações Interpessoais , Masculino , Testes Neuropsicológicos , Valor Preditivo dos Testes , Escalas de Graduação Psiquiátrica , Reconhecimento Psicológico , Adulto JovemRESUMO
BACKGROUND: Prior research on the nature of the vulnerability of neuroticism to psychopathology suggests biases in information processing towards emotional rather than neutral information. It is unclear to what extent this relationship can be explained by genetic or environmental factors. METHOD: The genetic relationship between a neuroticism composite score and free recall of pleasant and unpleasant words and the reaction time on negative probes (dot-probe task) was investigated in 125 female twin pairs. Interaction effects were modelled to test whether the correlation between neuroticism and cognitive measures depended on the level of the neuroticism score. RESULTS: The only significant correlation was between neuroticism and the proportion of recalled unpleasant words (heritability is 30%), and was only detectable at the higher end of the neuroticism distribution. This interaction effect seems to be due to environmental effects that make people in the same family more similar (e.g. parental discipline style), rather than genetic factors. An interesting sub-finding was that faster reaction times for left versus right visual field probes in the dot-probe task suggest that cognitive processing in the right hemisphere is more sensitive to subliminal (biologically relevant) cues and that this characteristic is under substantial genetic control (49%). Individual differences in reaction times on right visual field probes were due to environmental effects only. CONCLUSIONS: There is no evidence that the predisposition of individuals to focus on negative (emotional) stimuli is a possible underlying genetic mechanism of neuroticism.
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Atenção , Rememoração Mental , Transtornos Neuróticos/genética , Transtornos Neuróticos/psicologia , Adolescente , Adulto , Cognição , Sinais (Psicologia) , Feminino , Predisposição Genética para Doença/genética , Predisposição Genética para Doença/psicologia , Humanos , Tempo de Reação , Estimulação Subliminar , Análise e Desempenho de Tarefas , Gêmeos/psicologia , Adulto JovemRESUMO
This paper aims to report on the perception of emotional prosody in schizophrenia and to discuss its relationship with performance on neurocognitive measures. It consists of a comparison of 20 clinically stable schizophrenia patients with 20 healthy controls. Schizophrenia patients were impaired in emotional prosody perception, in particular in the perception of negative emotions. This impairment could not be explained on the basis of task difficulty or a general impairment in the decoding of speech intonation. Emotional prosody perception correlated moderately strongly with neurocognitive measures. We did not find a negative bias in the perception of emotional prosody.
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Afeto , Transtornos da Percepção/etiologia , Esquizofrenia/complicações , Fala , Adulto , Atenção , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Humanos , Inteligência , Testes Neuropsicológicos , Transtornos da Percepção/diagnóstico , Índice de Gravidade de DoençaRESUMO
BACKGROUND: In ageing populations fear of falling is an important issue. International studies and collaborations require scales suitable to more cultures. Scales developed in one culture require adaptation and additional investigation of psychometric properties for use in other countries. OBJECTIVE: To investigate the psychometric properties of a Dutch version of the Activities-specific Balance Confidence scale (ABC-NL) and whether adding questions about complex/dual tasks improves the discriminatory power. METHOD: Subjects were 106 men and 140 women aged 65-92 years. Measures were the 16-item ABC-NL and seven additional more complex items, fall history, general and physical self-efficacy, a functional reach test and a balance platform test. RESULTS: The ABC-NL had a weak ceiling effect. Internal consistency (Cronbachs alpha) was high. The relationship between ABC-NL and physical self-efficacy was significantly stronger than between the ABC-NL and general self-efficacy. Relationships with performance-based measures of balance were moderate. Differences between fallers and non-fallers and between activity avoiders and non-avoiders were significant. Adding questions about complex tasks hardly improved discriminatory power, reliability and validity. CONCLUSION: Psychometric properties of the ABC-NL were satisfactory. Further research is needed for use in high-functioning older persons.
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Acidentes por Quedas , Medo/psicologia , Avaliação Geriátrica , Equilíbrio Postural/fisiologia , Autoeficácia , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , PsicometriaRESUMO
Is the Activities-specific Balance Confidence Scale suitable for Dutch older persons living in the community? Background: In ageing populations fear of falling is an important issue. International studies and collaborations require scales suitable to more cultures. Scales developed in one culture require adaptation and additional investigation of psychometric properties for use in other countries.Objective: To investigate the psychometric properties of a Dutch version of the Activities-specific Balance Confidence scale (ABC-NL) and whether adding questions about complex/dual tasks improves the discriminatory power.Method: Subjects were 106 men and 140 women aged 65-92 years. Measures were the 16-item ABC-NL and seven additional more complex items, fall history, general and physical self-efficacy, a functional reach test and a balance platform test.Results: The ABC-NL had a weak ceiling effect. Internal consistency (Cronbachs alpha) was high. The relationship between ABC-NL and physical self-efficacy was significantly stronger than between the ABC-NL and general self-efficacy. Relationships with performance-based measures of balance were moderate. Differences between fallers and non-fallers and between activity avoiders and non-avoiders were significant. Adding questions about complex tasks hardly improved discriminatory power, reliability and validity.Conclusion: Psychometric properties of the ABC-NL were satisfactory. Further research is needed for use in high-functioning older persons.
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Previous explanations for the variability in success of compensating for homonymous hemianopia (HH) has been in terms of extent of the brain injury. In using on-line eye movement registrations, we simulated HH in 16 healthy subjects and compared their scanning performance on a dot counting task to their own "normal" condition and to real HH patients' performance. We evidenced clear parallels between simulated and real HH, suggesting that hemianopic scanning behaviour is primarily visually elicited, namely by the visual field defect, and not by the additional brain damage. We further observed age-related processes in compensating for the HH.
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Transtornos da Visão/fisiopatologia , Adolescente , Adulto , Idoso , Envelhecimento , Lesões Encefálicas/complicações , Estudos de Casos e Controles , Movimentos Oculares , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Transtornos da Visão/etiologia , Campos VisuaisRESUMO
Multi-component models of visual hemi-neglect have postulated that visual hemi-neglect is characterised by various attentional deficits. A grey scales task has been developed to quantify the early, automatic, (perhaps obligatory) ipsilesional orienting of visual attention, frequently assumed as the first of these attentional deficits. Explanations for this attentional imbalance are up until now mainly formulated in terms of right hemisphere activation. This lateral attentional bias has also been demonstrated in controls, in whom it is expressed as a leftward perceptual asymmetry. We reproduced previous literature findings on a grey scales task, considering controls and neglect patients. Three patients with neglect showed an extreme ipsilesional lateral bias. This bias did not change during or after cognitive rehabilitation. Additionally, we presented this grey scale task to 32 patients with left- and right-sided homonymous hemianopia (HP). HP is the loss of sight in one visual hemi-field. The HH patients had no clinical signs of impaired lateralised attention. Results revealed that HH patients showed a similar ipsilesional bias, albeit to a lesser degree than in neglect. Left-sided HH patients presented a quantitatively similar, but qualitatively opposite bias than the right-sided HH patients. We suggest that sensory effects can be an alternative source of attentional imbalance, which can interact with the previously proposed (right) hemispheric effects. This suggests that the perceptual asymmetry in the grey scales task is not necessarily an indicator of impaired right hemisphere attention. It rather suggests a pattern of functional cerebral asymmetry, which can also be caused by asymmetric sensory input.
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Atenção/fisiologia , Dominância Cerebral/fisiologia , Hemianopsia/fisiopatologia , Testes Neuropsicológicos , Orientação/fisiologia , Transtornos da Percepção/fisiopatologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Dano Encefálico Crônico/diagnóstico , Dano Encefálico Crônico/fisiopatologia , Córtex Cerebral/fisiopatologia , Feminino , Hemianopsia/diagnóstico , Hemiplegia/diagnóstico , Hemiplegia/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos da Percepção/diagnósticoRESUMO
The aim of this study was to gain insight in the prevalence of cognitive impairments among active older drivers and in driving performance of cognitively impaired ones. The study was implemented in the existing Dutch relicensing procedure for older drivers and consisted of three evaluation moments: a medical screening (for all subjects), a neuropsychological assessment and a test-drive (for candidates with cognitive impairments). In total, 2992 drivers were medically evaluated. In 4% of cases indications for impaired cognitive functioning were observed that could be evaluated and confirmed with neuropsychological tests. Eighty subjects performed an on-road test. Of these subjects, 57% were allowed to renew their driver's license, while in the remaining 43% no new licenses or restricted licenses were issued. During the test-drive, slow reactions and attention deficits were the most important causes for impaired fitness to drive.
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Envelhecimento/psicologia , Atenção , Exame para Habilitação de Motoristas/estatística & dados numéricos , Condução de Veículo/psicologia , Transtornos Cognitivos/diagnóstico , Tempo de Reação , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Condução de Veículo/legislação & jurisprudência , Transtornos Cognitivos/epidemiologia , Feminino , Humanos , Masculino , Programas de Rastreamento/métodos , Países Baixos/epidemiologia , Testes Neuropsicológicos , Escalas de Graduação Psiquiátrica , Distribuição por SexoRESUMO
BACKGROUND: In today's aging society, preventing or reducing disability is important. Physical activity may serve this goal. Generally, physical activity aims to enhance physical fitness, which in turn may prevent disability. The relationship between physical fitness and disability has been much less explored than the relationship between physical activity and physical fitness. OBJECTIVE: To investigate the relationship between separate components of physical fitness and disability. METHODS: The subjects were a community-based sample of 176 men and 233 women aged 65 years or older. Physical fitness was assessed with performance-based tests. Disability and potential confounders were assessed during face-to-face interviews. RESULTS: Independently of other fitness components, walking endurance, grip strength, manual dexterity and balance contributed significantly to the prediction of disability for both men and women. Flexibility of the hip and spine, flexibility of the shoulder and reaction time were not independent predictors of disability for men or women. Physical fitness explained a greater percentage of variance in disability for women (31-48%) than for men (14-34%). Although depressive symptoms, cognitive functioning (men), number of chronic conditions (women) and age (women) explained additional variance in disability, these variables did not confound the relationship between physical fitness and disability. CONCLUSION: Walking endurance, grip strength and manual dexterity are important unique predictors of disability. Physical activity programs should be directed at these fitness components.
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Atividades Cotidianas , Pessoas com Deficiência/reabilitação , Resistência Física , Aptidão Física , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Avaliação da Deficiência , Feminino , Serviços de Saúde para Idosos , Humanos , Masculino , Valor Preditivo dos TestesRESUMO
This paper is a literature review on assessment of fitness to drive in older drivers with cognitive impairment. Early studies on dementia and driving generally failed to distinguish between safe and unsafe drivers on the basis of cognitive test performance. Predictive studies demonstrated that cognitively impaired persons as a group perform significantly worse than controls on both neuropsychological and driving measures. A high prevalence of cognitive impairment was found in groups of older drivers involved in traffic accidents and crashes. However, a large range in neuropsychological test scores has been found. Low to moderate correlations could be established between neuropsychological test results and on-road driving performance, making it difficult to discriminate between cognitively impaired subjects who are fit or unfit to drive. The review concludes with a discussion of methodological difficulties in the field of dementia and driving, including participant selection, the choice of neuropsychological tests, and the operationalization of driving performance.
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Condução de Veículo/psicologia , Transtornos Cognitivos/psicologia , Acidentes de Trânsito , Idoso , HumanosRESUMO
Neuropsychological tests known to reveal abnormalities in patients with frontal lobe damage were used to explore cognitive function in 20 chronic schizophrenic patients. Eleven control subjects, matched on age and NLV-IQ (NLV is the Dutch version of the NART) were also tested. No impairments of planning ability were found on either the Action Program test or the Zoomap test, both subtests from the BADS (Behavioural Assessment of the Dysexecutive Syndrome). No abnormalities were apparent on tests of reactive flexibility, measured by task-switching and by the Rule Shift Cards test, also a subtest of the BADS. Patients with schizophrenia, however, had significantly greater difficulty in inhibiting irrelevant information and in generating words in a verbal fluency task, a measure of spontaneous flexibility.
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Transtornos Cognitivos/etiologia , Lobo Frontal/fisiopatologia , Inibição Psicológica , Esquizofrenia/fisiopatologia , Adulto , Doença Crônica , Transtornos Cognitivos/diagnóstico , Feminino , Humanos , Masculino , Transtornos Psicomotores/diagnóstico , Transtornos Psicomotores/etiologia , Índice de Gravidade de DoençaRESUMO
As an explanation of the pattern of slow information processing after closed head injury (CHI), hypotheses of impaired access to declarative memory and intact application and acquisition of procedural memory after CHI are presented. These two hypotheses were tested by means of four cognitive reaction-time tasks, a semantic memory task, a memory comparison task, a mental rotation task and a mirror reading task. These tasks were administered on two different days to 12 survivors of a CHI tested more than 5 years after injury and a healthy control group of comparable age and education. In three tasks the difficulty of access to declarative knowledge was varied and it was expected that this would slow the CHI group more than the controls. In two tasks opportunities for procedural learning were provided by repeatedly presenting the same cognitive tasks and in one task, the difficulty of access to procedural memory was varied. It was expected that the CHI group would profit as much from this as would the control group. Both hypotheses were supported.
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Lesões Encefálicas/etiologia , Traumatismos Cranianos Fechados/complicações , Transtornos da Memória/diagnóstico , Adolescente , Adulto , Amnésia Retrógrada/diagnóstico , Amnésia Retrógrada/etiologia , Feminino , Escala de Coma de Glasgow , Humanos , Masculino , Transtornos da Memória/etiologia , Processos Mentais , Pessoa de Meia-Idade , Testes Neuropsicológicos , Desempenho Psicomotor , Tempo de ReaçãoRESUMO
Self-evaluations by adults (varying in age from 45-92 years) of their memory and learning abilities were investigated and related to performance on laboratory and ecological memory tasks. Hardly any association was found between subjective and objective measures. Self-evaluations were strongly influenced by (systematically varied) frames of reference: optimistic in comparisons with other people, pessimistic in comparisons with their own previous level of functioning. The most frequent problems were 'learning something new' and 'remembering names'. In contrast to external memory aids, cognitive strategies were rarely used spontaneously. Strategy training led to significant improvement of performance, that remained stable at follow-up. A further opportunity for improving performance was realized by ergonomic adaptations of computerized systems (teleshopping). Problems in learning to use such systems were strongly reduced by decreasing the load on working memory and by adapting the system to existing knowledge and skills of the users. A general observation in the different projects was that age-differences could explain only a small percentage of the variance in subjective and objective memory measures.
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Envelhecimento/fisiologia , Aprendizagem/fisiologia , Memória/fisiologia , Adaptação Psicológica , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/psicologia , Alfabetização Digital , Estudos Transversais , Ergonomia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Países Baixos , Autoavaliação (Psicologia)RESUMO
The number of older drivers in Sweden will be rapidly increasing during the next decades. A possible relationship exists between the increased relative crash risk of older drivers and the prevalence of age-related diseases such as dementia. However, a clear-cut policy for evaluating driving competence in demented persons is still lacking. In recognition of this fact, the Swedish National Road Administration invited a group of researchers to formulate a consensus on the issue of driving and dementia. This consensus document is aimed at providing primary care physicians with practical advice concerning the assessment of cognitive status in relation to driving. Suggestions are based on a review of existing research and discuss the use of general and driving-specific sources of information available to the physician. Consensus was reached on the statement that a diagnosis of moderate to severe dementia precludes driving and that certain individuals with mild dementia should be considered for a specialized assessment of their driving competence.
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Demência , Análise e Desempenho de Tarefas , Idoso , Tomada de Decisões , Feminino , Humanos , Masculino , Fatores de Risco , SuéciaRESUMO
The assessment of fitness to drive in patients with closed head injury (CHI) does not usually include executive functioning. Executive functions may be particularly important for the tactical (e.g. anticipatory adaptation of speed) and strategical (e.g. choice of route and time) aspects of driving. The literature lacks evidence on the tactical aspects, which are critical in the assessment of actual driving. Executive functioning was therefore assessed in a task context relevant to tactical decision making in driving. Twenty very severe chronic CHI patients and 20 healthy control subjects were tested with a driving simulator test and an extended neuropsychological test battery. In the driving simulator test, executive function was operationally defined as the flexible adaptation to changing task demands. A specific feature of the test was the experimental control for slow information processing, a persistent sequel of severe CHI. Given this control for slow information processing, it was found that patients were unimpaired in their flexible adaptations. Similar findings were obtained with a neuropsychological test battery. Patients were consistently slower, but planning and flexibility were found to be unimpaired.
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This study describes the long-term deficits of a patient who, after a toxic encephalopathy, sustained extensive bilateral damage to both segments of the globus pallidus (GP) and the right substantia nigra (SN). There were no signs of lesions of the pyramidal tracts or of other motor structures. The most obvious deficits were an abnormal gait with an exaggerated knee extension and a tendency to fall slowly, especially when pushed backward. In contrast, Romberg's test on an unstable platform was normal, as were long-latency leg reflexes induced by perturbations. Inadequate anticipatory and compensatory postural responses, in particular across the hip and knee joints, and slow movements seemed responsible for the falls. Muscle tone was normal but reflex studies showed signs of abnormal facilitation and inhibition at various levels of the neuraxis. We conclude that the GP and SN lesions caused defective input to premotor cortical and brain stem target zones. Dysfunctioning of these zones leads to improper control of the descending ventromedial motor system responsible for locomotion, postural control, and reflex status. The deficits in upper extremity motor performance included delayed and slow movements, inaccurate amplitudes of ballistic responses, a lack of predictive control, and deficits in bimanual coordination. Sensory feedback, proprioceptive more than visual, played a powerful compensating role in rapid aiming movements. Regional blood flow (studied using 15(O)2) was reduced in multiple frontal cortical regions, among which are the hand areas of the supplementary and premotor cortex. We hypothesize that this reflected impaired functioning of these areas, caused by defective bilateral output from GP and SN, and resulting in the motor deficits of the arm and hand.