The use of CANTAB and language tests in healthy and pathological aging
Posted on 12 March 2015 in Clinical Trials / Research
'CANTAB and language tests to search for the limits between normal and pathological aging' was recently inducted into the Cantab Bibliography, corresponding author Cristovam W Picanço Diniz explains more about the research study.
Background and Methods
The recognition of the limits between normal and pathological aging is essential to start preventive actions (Daffner, 2010). Although there is an extensive literature on the use of cognitive tests to assess these limits, it is of interest to detect with safety and precision the subtle cognitive deficits of healthy aging. Healthy aging cognitive deficits includes memory, executive functions, information processing speed (Harada et al., 2013) and cortical functions of higher hierarchy such as attention (Glisky, 2007) and language (Burke and Mackay, 1997), see also (Wagster) (Wagster, 2009) for review.
We recently published an exploratory comparative study (Soares et al., 2015) regarding the power of detection of subtle differences in cognitive performances in young adults and cognitively healthy elderly by using CANTAB and language tests. We performed a cross-sectional neuropsychological evaluation of 60 individuals grouped as older aged (74.1±1.15 years, n=31) and young adults (29.9±1.06 years, n=29). Cognitively healthy individuals, with normal MMSE performances, were assessed using language and CANTAB tests and their scores on these tests were submitted to cluster and discriminant analysis.
Summary of our findings and their implications
As expected, significant differences in the performances of aged and young adults were detected in both language (Reduced Boston Naming, Narrative Performance on the Boston “cookies theft picture” description, Metaphors; Emotional and Linguistic Prosody) and visuospatial memory tests (PAL, SWM, DMS, RTI, RVP). However, intragroup cluster and discriminant analysis revealed that CANTAB tests, as compared to language tests, were able to detect subtle but significant differences between clusters of individuals in both young adults and aged voluntaries with higher resolution. These results indicates that rapid visual processing - RVP (sensitive to sustained attention) and reaction time - RTI (sensitive to motor and mental response speeds, as well as movement time, reaction time, response accuracy and impulsivity) are accurate and sensitive tools for assessing the cognitive function and the neuropsychological screening of the aging population.
In summary, the effects of aging on neuropsychological tests results revealed that the visual memory selected tests from CANTAB are more sensitive than language tests and better discriminates clusters of distinct performances in both young adults and aged voluntaries. We concluded that the large-scale application of CANTAB tests, both in longitudinal and in cross-sectional studies, will increase our ability to distinguish the limits between normal and pathological aging.
Why we chose CANTAB?
To be reliable, neuropsychological tests must replicate results in a systematic way when subjects are tested repeatedly. To be valid, the tests must be able to identify individuals with the same type of neuroanatomical change, which exhibit similar and consistent test performances for the same cognitive domain and with the same sensitivity. To be specific, the tests must be sensitive to the functional changes of interest, but not to others (Rabbitt and Lowe, 2000). Because these conditions were met and consistent CANTAB was considered reliable to assess the type and degree of functional loss and the specificity of aging-associated changes in the temporal and prefrontal lobes (Chase et al., 2008; De Rover et al., 2011). Because a large number of individuals were assessed by CANTAB it was possible to establish the degree of correlation between the functional demand imposed by the selected tests and the neural areas involved in those functions (Robbins et al., 1994; Robbins et al., 1998a; Rabbitt and Lowe, 2000).
CANTAB evaluates cognitive status using nonverbal stimuli with touchscreen technology and is therefore suitable for studies in experimental animals and humans. This battery was originally designed to adapt paradigms applied to animal models for use in humans using computational platforms (Robbins et al., 1994; Robbins et al., 1998b; Santos-Filho et al., 2014). By using visually attractive stimuli and nonverbal responses, CANTAB allows, where appropriate, to reduce or enlarge the level of difficulty of a given task adapting the test to a wide variety of cognitive performances, keeping the interest during the tests (Sahakian and Owen, 1992).
Automated test batteries allow the experimenter to apply the required tests without interference from the experimenter in data collection, reducing the chances of potentially present bias, when the interaction between the tested volunteer and the experimenter. Additionally CANTAB allows prompt interspecific comparison, within and between groups, in cross-sectional and longitudinal studies using the same equipment and the same technique to collect the information of interest (Sahakian and Owen, 1992).
Although we do not yet have a large sample to define norms and cutoff points for the Brazilian population using CANTAB, the battery of tests used is largely independent of cultural differences (De Luca et al., 2003; Simpson et al., 2005; Zürcher et al., 2010; Weissberger et al., 2013). Indeed, our findings are in agreement with a number of previous studies with CANTAB (Robbins et al., 1994; Robbins et al., 1998b; De Luca et al., 2003; Smith et al., 2013) that confirm age-related cognitive decline in selected tests for both temporal and prefrontal lobe functions. Because the neuropsychological test results from CANTAB have been validated in many countries with different cultures (Robbins et al., 1994; De Luca et al., 2003; Lee et al., 2013; Mcphee et al., 2013) we believe CANTAB to be a suitable tool for transnational comparative studies of both normal and pathological aging.
Future investigation perspectives
This study is part of a systematic effort that the research group of the Laboratory of Investigations in Chronic Neurodegeneration and Infection at the Federal University of Para (Brazil) has been doing to provide translational information on the normal and altered neurobiology of aging.
The long-term main goal is to enable evidence based public policies for health aging in the Amazon Region. Our team is dedicated to investigate the underline neurobiology basis of the beneficial effects of non-pharmacological intervention programs on cognition in healthy adults and elderly. We are analyzing peripheral blood biomarkers and cognitive status using CANTAB and language tests to discriminate subtle but significant changes associated with sedentary and active lifestyles and cardiovascular risk factors.
Author: Cristovam W Picanço Diniz, MD, PhD
Hospital Universitário João de Barros Barreto, Brazil
Study authors: Fernanda Cabral Soares, Thaís Cristina Galdino De Oliveira, Liliane Dias E Dias De Macedo, Alessandra Mendonça Tomás, Carmelina De Nazaré Monteiro Da Costa, Paola Geannine Reis Corrêa, Victor Oliveira Da Costa, Naina Yuki Jardim, João Bento-Torres, Cristovam Wanderley Picanço-Diniz, Natáli Valim Oliver Bento-Torres