| Abstract |
Aim: Under conditions of high demand for primary care services in an environment of low financial resources, there is need for brief, easily administered cognitive screening tools for use in the Primary Health Care setting, especially in rural areas. In Greece, the application of cognitive detection scales and the assessment of dementia caregivers’ burden in the community is inadequate. The aim of the current PhD dissertation was the literature search, identification, selection, translation into greek, standardization and adaptation of screening tools for use in routine practice by the general practitioner in order to detect cognitive disorders and dementia and to assess dementia caregivers’ burden in the community. Among the secondary objectives of the study was the assessment of the basic psychometric properties of the selected tools (reliability, validity, sensitivity, specificity, positive and negative predictive values) the Greek culturally adapted screening tools in everyday clinical practice of general practitioners in Primary Health Care.
Study Population and Methods: A cross-sectional epidemiological study was conducted. In principle, the translation, cultural adaptation and standardization of the TYM Test in a Greek population was carried out and its psychometric properties, concurrent and clinical validity were assessed in a community adult sample and a group of patients in General Hospital Neurology Clinics reported memory complaints. The final Greek version of the TYM was applied to 239 community dwelling individuals aged 21-92 years between July 2010 and September 2012. The elderly were recruited from four regions (Athens-Attica, Crete, Thrace and Macedonia) and all reported a negative history of neurological or psychiatric disease. In order to assess the clinical value of the TYM, data were also obtained from a group of 134 consecutive patients aged 46-88 years assessed for subjective memory complaints and were also recruited at the Neurology Clinic of PAGNH (Heraklion) as well as at three other regional general hospitals (Rethymnon, Chania and Tripolis) between March 2011 and October 2012. All community participants and all patients were administered the TYM. Moreover, a random community subsample and the majority of the clinical sample was also administered the MMSE, a depression and an independent living capacity scale. Identification and assessment of patients served one chief purpose, namely obtaining TYM and MMSE data on well-characterized and diagnosed cases of probable AD, MCI and other non-dementing neurological conditions in order to assess the sensitivity of the TYM against clinical diagnosis and to evaluate its potential utility for future use in the primary care setting. Concurrent validity data were examined on (1) the MMSE administered to 294 persons aged 21–89 years (mean 64.54 ± 16.28, with 8.35 ± 3.95 years of self-reported formal education, including 123 patients) and (2) the Greek Everyday Function Scale (GEFS) assessing independent living capacity (Publication 1).
In order to establish basic psychometric properties of TYM and GPCog (Patient Scale), these tools were applied in a random community-dwelling sample of Greek elders in rural primary care facilities in Greece, including evaluation of their sensitivity to health-related variables and the clinical validity of TYM and GPCog was determined as screening tools for assessing risk for cognitive impairment through comparison with scores in MMSE (as a reference standard). The sample included 319 community dwelling elders aged 60 to 89 years who were randomly selected from a larger epidemiological cohort (N = 3140) of visitors in 14 PHC units (11 located in rural and semi-urban areas) in the Prefecture of Heraklion-Crete over a 12-month period (March 2013-May 2014). The sample comprised 64.6% (n = 206) females and 35.4% (n = 113) males. The MMSE, TYM, and GPCog instruments were applied in random order across participants.
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The data analysis focused on a) the contribution of demographic factors on each tool and in comparison to the MMSE scale and b) the optimal cut-offs in scoring (23/24 points as a reference value), against which sensitivity, specificity as regards Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of each test estimated through ROC analyses (Publication 2).
Results: Data from the random rural sample of community dwelling elders in rural areas indicate that both TYM and GPCog display comparable internal consistency properties (0.77 and 0.79 respectively) to the MMSE scale (0.80) (Publication 2). These estimates were identical to those in the original TYM standardization study (Cronbach's a = 0.799 to 0.80 versus a = 0.80) and those obtained in a clinical sample of elderly in Greece (a = 0.77) (Publication 1). Internal consistency estimations for GPCog were also very alike the original standardization study. The correlation between education and TYM total score controlling for age remained statistically significant (r = 0.45, p = 0.0001), as was the correlation between age and TYM controlling for years of education (r = –0.36, p = 0.0001). Furthermore, women tended to score higher than men on the TYM and the gender gap became larger with advanced age. For the estimation of concurrent validity in the community sample, the zero-order correlation between total TYM and MMSE scores was found 0.73 (r = 0.59 when controlling for age and educational level). In the clinical sample, the strength of the association between TYM and MMSE scores was slightly higher (r = 0.82) among patients and remained virtually unchanged after controlling for age and education (partial r = 0.78). The relationship between TYM and MMSE was slightly higher (r = 0.82) among patients and remained essentially unchanged after age and education control (partial r = 0.78). Scores on both instruments were moderately associated with everyday functional capacity. Using age and education cut-offs ranging from 26/50 to 45/50 points, the sensitivity of the TYM for Alzheimer's disease detection was found to be higher than that of the MMSE (0.82 vs. 0.70 ) although its specificity was lower (0.71 vs. 0.90) (Publication 1).
The effect of age on scores of the three screening tools (MMSE, TYM and GPCog) was mainly linear. The effect of education level was stronger for individuals with fewer years of formal schooling. Moderated regression analyses established that the magnitude of associations between TYM-MMSE and GPCog-MMSE did not vary with education level. Interestingly, the effect of gender (higher age and education adjusted scores for men training) reached significance only for the MMSE scale. Given that one of the study objectives was on the clinical validity of TYM / GPCog as a function of education level of education, ROC analyzes were conducted separately for persons with low education (i.e., ≤ 5 years) and persons with higher education (≥ 6 years). A sensitivity of 80% and a specificity of 77% for TYM (35/36 or 38/39 cut-off, depending on education level) were found. The corresponding values were 89% and 61% for GPCog (7/8 cut-off), respectively (Publication 2).
Conclusion: In the context of Primary Health Care, the development of suitable and effective screening tools to identify individuals with cognitive disorders and deficits - with a view to further assessment - contributes to early dementia diagnosis. The Greek translated, culturally adapted and standardized version of the TYM and GPCog instruments proves to be accurate, reliable and well accepted for use by the general practitioner in routine clinical practice. The application of these tools to the elderly population can bring about outstanding benefits in rural areas (limited resources, low expertise in state supported primary health care systems and difficulty in accessibility), such as in the case of Greece where lately official recommendations for a screening tool use by primary care practitioners are established.
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