Browsing by Author "Martin, Ronald R."

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Open Access
Development of Scales that Measure Disorder Specific Intolerance of Uncertainty
(Faculty of Graduate Studies and Research, University of Regina, 2013-11) Thibodeau, Michel Albert; Asmundson, Gordon J.G.; Carleton, R. Nicholas; Wright, Kristi; Martin, Ronald R.; Radomsky, Adam
Evidence supports intolerance of uncertainty as an important feature of anxiety-based disorders and the construct may also play a role in major depressive disorder. Measures of intolerance of uncertainty have furthered understanding of the construct; however, existing questionnaires measure intolerance of uncertainty in a generalist fashion, not assessing the actual focus of uncertainty (e.g., what someone with panic disorder is uncertain about). This gap in research precludes conclusions regarding the nature of intolerance of uncertainty in anxiety-based disorders and major depressive disorder. The first objective of the study was to develop scales measuring disorder-specific intolerance of uncertainty (DSIU) for generalized anxiety disorder, social anxiety disorder, obsessivecompulsive disorder, posttraumatic stress disorder, health anxiety, panic disorder, specific phobia, and major depressive disorder. The second objective was to explore the relative contribution of DSIU to symptom severity beyond general (or non-specific) intolerance of uncertainty. The study included 920 university students from the University of Regina (n=360, 78% women, mean age=20.89) and the University of Houston (n=560, 86% women, mean age=22.94). Participants completed a bank of 137 items assessing DSIU and also completed symptom measures. Exploratory factor analyses and item characteristic curves highlighted items that warranted discard (addressing objective 1). Path analysis was conducted to explore the relationships between the constructs of interest (addressing objective 2). Exploratory factor analyses supported eight distinct factors across the DSIU items, reflecting the eight proposed scales. DSIU items generally did not crossload onto other DSIU scales or with items from symptom measures; however, items from the DSIU posttraumatic stress disorder scale overlapped substantially with the posttraumatic stress disorder symptoms measure. Examination of item characteristic curves demonstrated that most items measured the latent traits of interest along their full continuum; however, DSIU items for major depressive disorder and panic disorder did not discriminate between lower and medium levels of the latent traits. The finalized DSIU scales included an average of eight items and number of items ranged from 13 (social anxiety disorder) to six (specific phobia). The finalized scales exhibited excellent internal consistency in both samples (α.=86 to α.=95). Non-specific intolerance of uncertainty and DSIU predicted unique variance in symptoms of all disorders. DSIU and non-specific intolerance of uncertainty predicted symptoms of generalized anxiety disorder (β=31 vs. β=45), obsessive-compulsive disorder (β=40 vs. β=41), health anxiety (β=32 vs. β=45), specific phobia (β=22 vs. β=27), and major depressive disorder (β=32 vs. β=39) to a similar extent. DSIU predicted symptoms of social anxiety disorder (β=72 vs. β=18), panic disorder (β=60 vs. β=11) and posttraumatic stress disorder (β=61 vs. β=28) to a greater extent than non-specific intolerance of uncertainty. Individuals with social anxiety disorder, panic disorder, and posttraumatic stress disorder may be concerned primarily with uncertainty regarding situations specific to their symptoms (e.g., social situations in individuals with social anxiety disorder). Individuals with other disorders may also be relatively intolerant of uncertainty regarding other matters of every day life. Differences between these disorders related to DSIU may have implications for theories of how the disorders develop and how they are treated. Novel research using the DSIU scales is needed to further understanding of how DSIU and non-specific intolerance of uncertainty interact to underlie or exacerbate disorders.
Open Access
Long-term Neuropsychological and Psychosocial Consequences of Pediatric Mild Traumatic Brain Injury
(Faculty of Graduate Studies and Research, University of Regina, 2014-10) Makelki, Michelle Clareen; Alfano, Dennis; Sharpe, Donald A.; Wright, Kristi; Martin, Ronald R.; Ritchie, Lesley
Traumatic brain injury (TBI) is a major health problem affecting thousands of Canadians and their families each year. Little is known about the long-term consequences of pediatric mild traumatic brain injury (MTBI) on psychological functioning in adulthood. There are two major perspectives on this topic. The Kennard Principle asserts that young brains are more plastic and thus better suited to compensate following injury. The Early Vulnerability Hypothesis challenges this assertion with the idea that early damage to the brain may have significant implications for emerging cognitive and social skills. Executive function and social competence are skills that may be especially vulnerable to impairment following head injury in children. Executive function and social competence rely on frontal neural networks, which are particularly vulnerable to damage from MTBI. As frontal regions underlying executive functions and social competence are slower to mature, the outcome of these faculties following pediatric TBI cannot be accurately assessed until brain maturity has been reached. The present study thus examined the consequences of pediatric MTBI on executive functions and social skills in adulthood. Participants were undergraduate students from the University of Regina. A screening survey was administered to 1295 students to identify individuals with a history of head injury and those without. The study sample consisted of 24 participants with a history of head injury (HI) and 29 participants with no history of head injury. The average age of both groups approximated 20 years and the average time since injury for the HI group was 10.5 years. A comprehensive battery of executive functioning, emotion recognition, and psychosocial measures was administered to the participants. The principal results of the study revealed a statistically significant difference between the HI and Control group on the Global Deficit Score (GDS; a composite score computed using 22 individual objective and demographically-corrected tests of cognitive function), with the HI group also falling above the clinical cut-off for neuropsychological impairment on this measure. In addition, the GDS demonstrated an overall moderate level of diagnostic accuracy when evaluated using Receiver Operating Curve analysis. In terms of the individual objective cognitive tests, the HI group performed significantly more poorly on the PASAT compared to the Control group, suggesting particular difficulties in the areas of auditory attention and working memory, findings characteristic of executive dysfunction and the known pathophysiology of traumatic brain injury. On the Neuropsychological Impairment Scale, a broad-based self-report measure, the HI group endorsed significantly more symptoms of somatic and cognitive dysfunction than the Control group. Taken together, these results are consistent with the Early Vulnerability Hypothesis and suggest that childhood MTBI may be associated with subtle objective deficits in executive function, along with elevated somatic and cognitive symptomology in adulthood.