Tradução, adaptação e validação de construto do Teste do Relógio aplicado entre idosos no Brasil

OBJETIVO: Poucos estudos no Brasil investigaram a validação de testes cognitivos em amostras populacionais de idosos e nenhum deles analisou as propriedades psicométricas do Teste do Relógio de Tuokko. O objetivo do estudo foi traduzir e adaptar o modelo desse teste ao contexto brasileiro e avaliar sua validade de construto. MÉTODOS: Estudo transversal com uma amostra populacional constituída por 353 sujeitos de Juiz de Fora (MG), 2004-2005. Para avaliar as validades convergente e discriminante, utilizou-se a correlação de Pearson. Os subtestes do Teste do Relógio foram correlacionados com os instrumentos de referência: cubos e dígitos, e mini-exame do estado mental para avaliar a validade convergente. A validade discriminante foi investigada por meio da correlação dos subtestes com a Center for Epidemiologic Studies Depression Scale. RESULTADOS: Da amostra, 74,1% eram do sexo feminino, com idade entre 63 e 107 anos (73,8+8,5) e média de escolaridade foi 7,4 anos (DP=4,7). Obteve-se validade convergente, com correlações estatisticamente significativas entre todos os subtestes (p<0,01). Quanto à validade discriminante, o único subteste que teve correlação significativa com a escala de referência foi o "indicação das horas" (p<0,05). CONCLUSÕES: O Teste de Relógio traduzido e adaptado em uma amostra comunitária de idosos mostrou ser um instrumento de rastreio cognitivo breve, com boa validade de construto quando analisado com outros dados da literatura. Futuros trabalhos devem investigar outras propriedades psicométricas, como as validades de critério e de conteúdo.

Correlation between the CAMCOG, the MMSE, and three clock drawing tests in a specialized outpatient psychogeriatric service

Our objective was to assess the correlation between (1) the Cambridge Cognitive Examination (CAMCOG) (including the Mini-Mental State Examination [MMSE]) score and three clock drawing tests (CDT) and (2) the three CDTs independently, in a specialized outpatient psychogeriatric service. One hundred and fourteen subjects completed a comprehensive evaluation and were allocated to one of the following groups: dementia of the Alzheimer's type (DAT) in 52; vascular dementia (VD) in 36; non-dementia (ND; Mood or Anxiety Disorders) in 26. When the entire sample of patients is considered, all three CDTs used were highly and significantly correlated to the MMSE score, the CAMCOG score, and to each other. In this patient population, these cognitive tests may be interchangeable for providing an initial objective measure of cognitive function. However, when the same correlations were studied in the separate diagnostic groups, in the dementia group (DAT and VD) even though the high correlations between the various CDTs themselves did not change, the correlations between the MMSE score, the CAMCOG score and the CDTs decreased, more evidently in the VD group. This trend became even more conspicuous in the ND group, where some of the above mentioned correlations became non-significant. We hypothesize that in a real clinical situation the clinician initially assumes the role of cognitive "evaluator" (in terms of the total sample) followed by the role of cognitive "monitor" (in relation to specific diagnostic groups). In the first instance, CDTs, the MMSE, and the CAMCOG might be considered interchangeable as an initial objective measure of cognitive dysfunction, while in the second role, different CDTs might be diversely used, presumably supplemented by other cognitive tests and clinical methods.

Qualitative analyses of clock drawings in Alzheimer's disease and vascular dementia

Although quantitative analyses of clock drawings (CD) have achieved widespread clinical use as a cognitive screening, little is known about the qualitative profiles of CD in Alzheimer's disease (AD) and vascular dementia (VD). To address this issue, the present study examined the significance of qualitative analyses of CD in AD and VD. Sixty-seven AD patients, 44 VD patients and eight controls underwent a clock drawing test and took the Mini-Mental State Examinations (MMSE). In the dementia groups, quantitative scores significantly decreased compared with controls and were significantly correlated with MMSE scores. Qualitative analysis demonstrated that in AD patients qualitative error patterns were stable and independent of severity. In contrast, in VD patients the frequency of graphic difficulties and conceptual deficit increased, while the frequency of spatial and/or planning deficit decreased, as severity worsened. In mild dementia groups the frequency of spatial and/or planning deficit was significantly higher in VD. In moderate dementia groups, the frequency of graphic difficulties was significantly higher in VD and the difference in the frequency of spatial and/or planning deficit seen in mild dementia disappeared. The present study suggests that qualitative analyses of clock drawings could demonstrate the neuropsychological profiles of AD and VD and their differences between these dementias.

Clock-drawing: is it the ideal cognitive screening test?

OBJECTIVE

The clock-drawing test has achieved widespread clinical use in recent years as a cognitive screening instrument and a significant amount of literature relates to its psychometric properties and clinical utility. This review aims to synthesize the available evidence and assess the value of this screening test according to well-defined criteria.

DESIGN

A Medline and Psycho-info literature search of all languages was done from 1983 to 1998 including manual cross-referencing of bibliographies. A brief summary of all original scoring systems is provided as well as a review of replication studies. Psychometric data including correlations with other cognitive tests were recorded. Qualitative aspects of the test are also described.

RESULTS

Among published studies, the mean sensitivity (85%) and specificity (85%) of the clock-drawing test are impressive. Correlations with the Mini-Mental State Examination and other cognitive tests was high, generally greater than r = 0.5. High levels of inter-rater and test-re-test reliability and positive predictive value are recorded and despite significant variability in the scoring systems, all report similar psychometric properties. The clock test also shows a sensitivity to cognitive change with good predictive validity.

CONCLUSIONS

The clock-drawing test meets defined criteria for a cognitive screening instrument. It taps into a wide range of cognitive abilities including executive functions, is quick and easy to administer and score with excellent acceptability by subjects. Together with informant reports, the clock-drawing test is complementary to the widely used and validated Mini-Mental State Examination and should provide a significant advance in the early detection of dementia and in monitoring cognitive change. A simple scoring system with emphasis on the qualitative aspects of clock-drawing should maximize its utility.