Limits on using the clock drawing test as a measure to evaluate patients with neurological disorders.

BACKGROUND: The Clock Drawing Test (CDT) is used as a quick-to-conduct test for the diagnosis of dementia and a screening tool for cognitive impairments in neurological disorders. However, the association between the pattern of CDT impairments and the location of brain lesions has been controversial. We examined whether there is an association between the CDT scores and the location of brain lesions using the two available scoring systems. METHOD: One hundred five patients with brain lesions identified by CT scanning were recruited for this study. The Montreal Cognitive Assessment (MoCA) battery including the CDT were administered to all partcipants. To score the CDT, we used a qualitative scoring system devised by Rouleau et al. (1992). For the quantitative scoring system, we adapted the algorithm method used by Mendes-Santos et al. (2015) based on an earlier study by Sunderland et al. (1989). For analyses, a machine learning algorithm was used. RESULTS: Remarkably, 30% of the patients were not detected by the CDT. Quantitative and qualitative errors were categorized into different clusters. The classification algorithm did not differentiate the patients with traumatic brain injury 'TBI' from non-TBI, or the laterality of the lesion. In addition, the classification accuracy for identifying patients with specific lobe lesions was low, except for the parietal lobe with an accuracy of 63%. CONCLUSION: The CDT is not an accurate tool for detecting focal brain lesions. While the CDT still is beneficial for use with patients suspected of having a neurodegenerative disorder, it should be cautiously used with patients with focal neurological disorders.

Attention bias modification through transcranial direct current stimulation (tDCS): A review.

Attention bias is a tendency to preferably detect, orient and select emotionally valued stimuli, as compared to neutral stimuli, and plays a crucial role in the psychopathology of various psychiatric disorders. Transcranial direct current stimulation (tDCS) has been applied for the alteration of attention bias in health and disease with different parameters and conditions, but the contribution of these factors to the magnitude and directionality of effects has not previously been comprehensively reviewed. In this review, we aimed to systematically explore the effects of tDCS on attention bias in different tasks, tDCS conditions, and health states. Data were collected in accordance with the PRISMA approach. A literature search identified 22 original experiments that explored the effects of tDCS on attention bias. Determinants of tDCS effects on attention bias were cortical target areas, the specific task under study, stimulation parameters, and the presence of psychopathology. Relevant cortical areas for modification of attention bias via tDCS were the dorsolateral prefrontal cortex (dlPFC) and ventromedial prefrontal cortex (vmPFC). The observed heterogeneity of the impact of tDCS on the modulation of attention bias can be explained by the area of stimulation, valence of stimuli, task characteristics, and the intensity of stimulation.

Laterality in Emotional Language Processing in First and Second Language.

Language is a cognitive function that is asymmetrically distributed across both hemispheres, with left dominance for most linguistic operations. One key question of interest in cognitive neuroscience studies is related to the contribution of both hemispheres in bilingualism. Previous work shows a difference of both hemispheres for auditory processing of emotional and non-emotional words in bilinguals and monolinguals. In this study, we examined the differences between both hemispheres in the processing of emotional and non-emotional words of mother tongue language and foreign language. Sixty university students with Persian mother tongue and English as their second language were included. Differences between hemispheres were compared using the dichotic listening test. We tested the effect of hemisphere, language and emotion and their interaction. The right ear (associated with the left hemisphere) showed an advantage for the processing of all words in the first language, and positive words in the second language. Overall, our findings support previous studies reporting left-hemispheric dominance in late bilinguals for processing auditory stimuli.