Diagnostic Accuracy, Effectiveness and Cost for Cognitive Impairment and Dementia Screening of Three Short Cognitive Tests Applicable to Illiterates

Abstract

BackgroundIlliteracy, a universal problem, limits the utilization of the most widely used short cognitive tests. Our objective was to assess and compare the effectiveness and cost for cognitive impairment (CI) and dementia (DEM) screening of three short cognitive tests applicable to illiterates.MethodsPhase III diagnostic test evaluation study was performed during one year in four Primary Care centers, prospectively including individuals with suspicion of CI or DEM. All underwent the Eurotest, Memory Alteration Test (M@T), and Phototest, applied in a balanced manner. Clinical, functional, and cognitive studies were independently performed in a blinded fashion in a Cognitive Behavioral Neurology Unit, and the gold standard diagnosis was established by consensus of expert neurologists on the basis of these results. Effectiveness of tests was assessed as the proportion of correct diagnoses (diagnostic accuracy [DA]) and the kappa index of concordance (k) with respect to gold standard diagnoses. Costs were based on public prices at the time and hospital accounts.ResultsThe study included 139 individuals: 47 with DEM, 36 with CI, and 56 without CI. No significant differences in effectiveness were found among the tests. For DEM screening: Eurotest (k = 0.71 [0.59–0.83], DA = 0.87 [0.80–0.92]), M@T (k = 0.72 [0.60–0.84], DA = 0.87 [0.80–0.92]), Phototest (k = 0.70 [0.57–0.82], DA = 0.86 [0.79–0.91]). For CI screening: Eurotest (k = 0.67 [0.55–0.79]; DA = 0.83 [0.76–0.89]), M@T (k = 0.52 [0.37–0.67]; DA = 0.80 [0.72–0.86]), Phototest (k = 0.59 [0.46–0.72]; DA = 0.79 [0.71–0.86]). There were no differences in the cost of DEM screening, but the cost of CI screening was significantly higher with M@T (330.7±177.1€, mean±sd) than with Eurotest (294.1±195.0€) or Phototest (296.0±196.5€). Application time was shorter with Phototest (2.8±0.8 min) than with Eurotest (7.1±1.8 min) or M@T (6.8±2.2 min).ConclusionsEurotest, M@T, and Phototest are equally effective. Eurotest and Phototest are both less expensive options but Phototest is the most efficient, requiring the shortest application time.

Phototest: Normative data for the Portuguese population

“…The Phototest does not require any reading abilities and does not include pencil and paper tasks, thus making it a good choice for use with this population. 10 Therefore, further studies with illiterates are required. The concurrent validity of the test was determined with the MoCA, and this may have biased this indicator because the neuropsychological test was also used to includeeexclude participants from the sample.…”

“…The Phototest was developed in Spain and has proven high diagnostic accuracy and effectiveness for cognitive impairment and dementia, even when compared with more traditional screening tests such as the Mini-Mental State Examination 7e9 or the Memory Alteration Test. 10 It has been demonstrated that cutoff points of 26 and 28 offer satisfactory discriminant validity for Alzheimer's disease and cognitive impairment, respectively. 11 In addition, the test also has good testeretest and interobserver reliability.…”

“…12 Considering costs based on public prices and hospital accounts, the costs involved with the use of the Phototest are considerably lesser in comparison with other screening tests. 10,11 Because reading is not required and there are no pencil and paper tasks, this test is suitable for use with illiterates or individuals with a low level of education. 8 In the normative study 12 for the Spanish population, the Phototest results are normally distributed and are not influenced by sex or education but they are age dependent.…”

Utility of the Mini-Cog for Detection of Cognitive Impairment in Primary Care: Data from Two Spanish Studies

“…However, the Mini-Cog was not a valid choice in the studied sample, and this result, which was consistent with previous research, advise against the use of the Mini-Cog, particularly in settings where the proportion of unrecognized dementia is low. In these settings, the use of tests that offer a wider range of tasks and score, yet maintaining acceptability and feasibility, seems more adequate [38]. In light of the relevance of the detection of CI, more human and technical resources should be implemented in PC.…”

Evaluación de la utilidad diagnóstica de la versión española del cuestionario al informador «AD8»

“…El rendimiento diagnóstico global del AD8 es similar al mostrado en esta misma muestra por el Fototest (aROC 0,93, IC del 95%, 0,89–0,96; CC del 87,7%), un test cogni-tivo breve (< 3 min) aplicable a analfabetos y no influido por el nivel educativo 20 , que en nuestro medio ha mostrado una efectividad diagnóstica superior a la del MMSE 33 y mayor efi-ciencia que otros instrumentos aplicables a analfabetos 34 . Aunque la UD global es similar, para el mejor punto de corte (3/4) el AD8 es más sensible (S 0,93, IC del 95%, 0,88–0,96; E 0,81, IC del 95%, 0,72–0,88) en tanto que el Fototest (28/29) es más específico (S 0,83, IC del 95%, 0,77–0,88; E 0,96, IC del 95%, 0,89–0,99).…”