Mary Desrocher

Neurocognitive Correlates of Type 1 Diabetes Mellitus in Childhood

Type 1 Diabetes Mellitus (T1DM) is one of the most prevalent chronic health conditions in children under the age of 18 years. Complications of the disease include hypo- and hyperglycemia, which can have an impact on children’s performance in assessment situations, in the clinic, and in school. Because there is no cure for this disease, there is a need to understand the cognitive deficits associated with some of its complications, as this knowledge will impact on the choice of treatment regimens as well as educational interventions. This paper provides a comprehensive review of the relevant literature on the neurocognitive outcome of T1DM. In particular, disease- and treatment-related variables that are associated with poor performance on cognitive domains will be reviewed. Specifically, age of onset, duration, pubertal effects, and presence of hypoglycemia or hyperglycemia will be examined. These findings are not without controversy, and limitations to conclusions will also be presented. Where relevant, recommendations for future research directions will be provided.

Contextualizing the neurobiology of conduct disorder in an emotion dysregulation framework.

Conduct disorder (CD) represents the most common childhood psychiatric disorder found in community and mental health clinics. This paper provides a comprehensive review of the neurobiology of CD; specifically, neurological and neurochemical correlates. Converging evidence suggests that neurological profiles of individuals with CD, compared to peers, are characterized by reduced P300 brain wave amplitude, deactivation of the anterior cingulated cortex and reduced activation in the left amygdala in response to negative stimuli, and reduced right temporal lobe volume. The neurochemical profiles of individuals with CD are characterized by reduced serotonin and cortisol levels (i.e., decreased HPA axis function), as well as attenuated autonomic nervous system functioning. Popular theoretical frameworks cited within the CD literature are limited in their ability to explain and consolidate the neurological and neurochemical findings. We believe that emotion dysregulation theory, though not often used within CD research, may provide the most comprehensive and inclusive framework for understanding neurobiological aspects of this disorder. Limitations within the literature, future directions for research, and implications of the findings will be discussed.

Episodic and semantic autobiographical memory and everyday memory during late childhood and early adolescence

Few studies have examined both episodic and semantic autobiographical memory (AM) performance during late childhood and early adolescence. Using the newly developed Children’s Autobiographical Interview (CAI), the present study examined the effects of age and sex on episodic and semantic AM and everyday memory in 182 children and adolescents. Results indicated that episodic and semantic AM both improved between 8 and 16 years of age; however, age-related changes were larger for episodic AM than for semantic AM. In addition, females were found to recall more episodic AM details, but not more semantic AM details, than males. Importantly, this sex difference in episodic AM recall was attenuated under conditions of high retrieval support (i.e., the use of probing questions). The ability to clearly visualize past events at the time of recollection was related to children’s episodic AM recall performance, particularly the retrieval of perceptual details. Finally, similar age and sex effects were found between episodic AM and everyday memory ability (e.g., memory for everyday activities). More specifically, older participants and females exhibited better episodic AM and everyday memory performance than younger participants and males. Overall, the present study provides important new insight into both episodic and semantic AM performance, as well as the relation between episodic AM and everyday memory, during late childhood and adolescence.

Determinants of cognitive outcomes of perinatal and childhood stroke: A review

Our understanding of cognitive and behavioral outcomes of perinatal and childhood stroke is rapidly evolving. A current understanding of cognitive outcomes following pediatric stroke can inform prognosis and direct interventions and our understanding of plasticity in the developing brain. However, our understanding of these outcomes has been hampered by the notable heterogeneity that exists amongst the pediatric stroke population, as the influences of various demographic, cognitive, neurological, etiological, and psychosocial variables preclude broad generalizations about outcomes in any one cognitive domain. We therefore aimed to conduct a detailed overview of the published literature regarding the effects of age at stroke, time since stroke, sex, etiology, lesion characteristics (i.e., location, laterality, volume), neurologic impairment, and seizures on cognitive outcomes following pediatric stroke. A key theme arising from this review is the importance of interactive effects among variables on cognitive outcomes following pediatric stroke. Interactions particularly of note include the following: (a) age at Stroke x Lesion Location; (b) Lesion Characteristics (i.e., volume, location) x Neurologic Impairment; (c) Lesion Volume x Time Since Stroke; (d) Sex x Lesion Laterality; and (e) Seizures x Time Since Stroke. Further, it appears that these relationships do not always apply uniformly across cognitive domains but, rather, are contingent upon the cognitive ability in question. Implications for future research directions are discussed.

Circadian profiles of focal epileptic seizures: A need for reappraisal

Circadian rhythm of seizure is underestimated in the study of focal epilepsies. A review of the current literature revealed a clear correlation between cortical epileptogenic focus and the circadian phase of seizure peak occurrence in adult patients. A single diurnal peak at 19:00 was found in seizures originating from the occipital lobe, between 5:00 and 7:00 in frontal lobe seizures, and between 16:00 and 17:00 h in temporal lobe seizures. Two diurnal peaks, between 5:00 and 7:00, and at 23:00 are reported in seizures from the parietal lobe, and between 7:00 to 8:00 and 16:00 to 17:00 in mesial temporal onset seizures. This circadian character of seizure occurrence in focal epilepsies may not be unique to partial seizures since recent clinical and experimental data indicate that generalized seizures also demonstrate circadian effects. The clinical evidence on generalized seizures and epilepsies is not recent, but a formal integration of circadian rhythmicity in our understanding and clinical management of epilepsies may be warranted.

The effects of gender on the retrieval of episodic and semantic components of autobiographical memory.

Despite consistent evidence that women exhibit greater episodic memory specificity than men, little attention has been paid to gender differences in the production of episodic details during autobiographical recall under conditions of high and low retrieval support. Similarly the role of gender on the production of semantic details used to support autobiographical memory recollections of specific events has been largely unexplored. In the present study an undergraduate sample of 50 men and 50 women were assessed using the Autobiographical Interview (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002). Women recalled more episodic information compared to men in the high retrieval support condition, whereas no gender differences were found in the low retrieval support condition. In addition, women produced more repetitions compared to men in the high retrieval support condition. No gender differences were found in the production of semantic details. These results are interpreted in terms of gender differences in encoding and reminiscence practices. This research adds to the literature on gender differences in memory recall and suggests that gender is an important variable in explaining individual differences in AM recall.

INTRAPERSONAL AND EXTRAPERSONAL SPACE: PERFORMANCE OF OLDER ADULTS ON ECOLOGICALLY VALID ORIENTATION TASKS

ABSTRACT This experiment examined performance of 20 older adults (64 to 76 years) and 20 young adults (18 to 35 years) on two orientation tasks: The Intrapersonal task required participants to point to parts of their body corresponding to those on a line drawing; and, the Extrapersonal task involved translating a route indicated on paper to walking a route on a corresponding floor map. Older adults were found to be slower at completing both tasks, although accuracy of performance was comparable between age groups. The results were interpreted in terms of a speed-accuracy tradeoff that increases with age.

Working memory outcomes following unilateral arterial ischemic stroke in childhood

ABSTRACT There is a dearth of research examining working memory (WM) following pediatric arterial ischemic stroke (AIS). This study assesses the WM patterns of 32 children, aged 6 to 14 years, with a history of unilateral AIS and 32 controls using a paradigm based on Baddeley and Hitch’s multi-component WM model. The results indicate compromised WM in children with AIS relative to controls and parent reports confirm higher rates of dysfunction. Supplementary analyses of impairment confirm higher rates in children with AIS, ranging from 31.25% to 38.70% on performance-based measures and 50.00% on parent reports, compared to 0.00% to 21.88% on performance-based measures in controls and 15.63% on parent reports. Continual follow-up is recommended given that a subset of children with stroke appear to be at risk for WM impairment. Moreover, the subtle nature of WM challenges experienced by many children who have experienced a stroke increases the likelihood that WM impairment could go undetected. The long-term trajectories of WM in the pediatric stroke population remains unknown and future studies are needed to track changes in WM functioning over time.

Does stroke impair academic achievement in children? The role of metacognition in math and spelling outcomes following pediatric stroke

ABSTRACT Introduction: Current research suggests that pediatric stroke is associated with a reduction in intellectual functioning. However, less is known about academic achievement and the contribution of specific executive functions to math and literacy in this population. The current study investigates behavioral ratings of executive functioning and their relationship to math and spelling performance in children with a history of unilateral arterial ischemic stroke. Method: Thirty-two pediatric patients with stroke (Mage = 9.5 ± 2.7 years) and 32 demographically equivalent, healthy controls were tested on standardized measures of arithmetic, spelling, and intelligence. Executive functioning data were collected via standardized parent questionnaire. Results: Relative to controls, stroke participants demonstrated significantly poorer functioning in math, spelling, metacognition, and behavioral-regulation. Pencil and paper arithmetic was particularly challenging for the stroke group, with 40% of patients reaching levels of clinical impairment. Hierarchical regression in stroke participants further revealed that metacognition was a robust predictor of academic deficits. Stroke occurring in later childhood and affecting cortical and subcortical brain regions also presented as potential clinical risk factors. Conclusions: Children with stroke were especially vulnerable to math achievement deficits. Metacognition made a substantial contribution to academic achievement abilities among stroke patients, and results underscore the importance of early metacognitive skills in the completion of schoolwork. Results also emphasize that pediatric stroke patients are a heterogeneous group with regard to functioning and that there is value in examining standard score distributions of clinical participant samples.