Clock Drawing Test in acute stroke and its relationship with long-term functional and cognitive outcomes.

Objective: The Clock Drawing Test (CDT) is commonly used as a screening tool for the assessment of dementia. The association between the CDT in acute stroke and long-term functional and cognitive outcomes in this population is unknown. The present prospective study is the first to examine if CDT scores in the acute stage after stroke are related to long-term outcomes and to compare the predictive ability of two scoring systems in a large sample of stroke patients. Method: A total of 340 patients admitted to an acute stroke unit were included in the present study. Separate stepwise multiple linear regression analyses were performed with eight independent variables (demographic/pre-stroke variables - age, sex, premorbid functioning; stroke-related variables - stroke severity, localization; cognitive variables - Orientation Test, CDT [2 scoring systems]), and four dependent variables administered one year post-stroke (Barthel Index, modified Rankin Scale, Reintegration to Normal Living index, Global Deterioration Scale). Results: Although both CDT scoring methods were related to all long-term outcome measures, the more comprehensive scoring system was the only baseline variable that significantly explained the variance in outcome measures in all four multiple regression models. Conclusion: Performance on the CDT in acute stroke is related to long-term outcomes including patients' degree of independence in performing activities of daily living, the degree to which they achieved reintegration into daily occupations, and the degree of cognitive decline observed one-year post-stroke. Future studies are needed to clarify the nature of the relationship between different CDT scoring systems and post-stroke outcomes.

Measuring the Performance of Attention Networks with the Dalhousie Computerized Attention Battery (DalCAB): Methodology and Reliability in Healthy Adults.

Attention is an important, multifaceted cognitive domain that has been linked to three distinct, yet interacting, networks: alerting, orienting, and executive control. The measurement of attention and deficits of attention within these networks is critical to the assessment of many neurological and psychiatric conditions in both research and clinical settings. The Dalhousie Computerized Attention Battery (DalCAB) was created to assess attentional functions related to the three attention networks using a range of tasks including: simple reaction time, go/no-go, choice reaction time, dual task, flanker, item and location working memory, and visual search. The current study provides preliminary normative data, test-retest reliability (intraclass correlations) and practice effects in DalCAB performance 24-h after baseline for healthy young adults (n = 96, 18-31 years). Performance on the DalCAB tasks demonstrated Good to Very Good test-retest reliability for mean reaction time, while accuracy and difference measures (e.g., switch costs, interference effects, and working memory load effects) were most reliable for tasks that require more extensive cognitive processing (e.g., choice reaction time, flanker, dual task, and conjunction search). Practice effects were common and pronounced at the 24-h interval. In addition, performance related to specific within-task parameters of the DalCAB sub-tests provides preliminary support for future formal assessment of the convergent validity of our interpretation of the DalCAB as a potential clinical and research assessment tool for measuring aspects of attention related to the alerting, orienting, and executive control networks.

Measuring the components of attention using the Dalhousie Computerized Attention Battery (DalCAB).

Using experimentally validated tests to measure the vigilance/alerting, orienting and executive control attention networks, we have developed a novel, theoretically driven battery for measuring attentional abilities, called the Dalhousie Computerized Attention Battery (DalCAB). The current study sought to examine the factor structure of the DalCAB as preliminary evidence for its validation as an assessment tool for the above-named attention networks. One hundred young, healthy adult participants (18 to 31 years) completed the DalCAB (simple reaction time, choice reaction time, dual task, go/no-go, visual search, vertical flanker, and item memory tasks). Exploratory factor analysis of task performance with promax rotation highlighted a 9-factor model, accounting for 54.66% of the shared variance. Factors 1, 2, and 5 are associated with measures reflecting the vigilance/alerting network (response speed, maintenance/preparation and consistency, respectively), Factor 3 is associated with the orienting network (searching measures). Factors 4, 6, 7, and 8 are associated with different aspects of the executive control network including: inhibition, working memory, filtering, and switching. The final factor is associated with vigilance/alerting (fatigue) and executive control (proactive interference). Our model provides preliminary evidence for the validation of our interpretation of the DalCAB as a measure of vigilance/alerting, orienting, and executive control attentional abilities, and contributes to the previously reported evidence for the validation of these tasks for measuring different aspects of attention. We also demonstrate the importance of each of the specific measures derived from the DalCAB tasks, and our results provide further behavioral evidence of the existence of multiple attention-related networks.

Ready, set, point: the effects of alertness on prism adaptation in healthy adults.

Prism adaptation (PA) is a promising rehabilitation technique for visuo-spatial neglect, an attention disorder that is characterized by spatial attention deficits (i.e., deficits in orienting). PA involves visuo-motor adaptation to rightward shifting prism goggles. Following goggle removal, this adaptation results in leftward shifts in visuo-motor aiming and amelioration of spatial neglect. Even though some studies clearly support the beneficial effects of PA for spatial neglect, not all studies find benefits, thus it remains unclear how PA effects could be improved. Taking advantage of the known interactions between orienting and alerting reported in the attention literature (i.e., alerting enhances orienting function; e.g., Ishigami and Klein in J Individ Differ 30:220-237. doi: 10.1027/1614-0001.30.4.220 , 2009, in J Neurosci Methods 190:117-28. doi: 10.1016/j.jneumeth.2010.04.019 , 2010; Robertson et al. in Nature 395:169-72. doi: 10.1038/25993 , 1998), we examined the effects of alerting tones on PA with healthy young and older adults. We found that the effects of alerting on PA with young adults were negative, while there was a positive effect with older adults, specifically on a visuo-motor outcome task. Thus, enhancement of PA effects by alerting may be age specific and task specific. Therefore, we can conclude that while the impact of alerting tones is not always positive, further research in patients with neglect may be warranted.