Cluster Analysis of Symptoms Among Patients with Upper Extremity Musculoskeletal Disorders

Introduction Some musculoskeletal disorders of the upper extremity are not readily classified. The study objective was to determine if there were symptom patterns in self-identified repetitive strain injury (RSI) patients. Methods Members (n = 700) of the Dutch RSI Patients Association filled out a detailed symptom questionnaire. Factor analysis followed by cluster analysis grouped correlated symptoms. Results Eight clusters, based largely on symptom severity and quality were formulated. All but one cluster showed diffuse symptoms; the exception was characterized by bilateral symptoms of stiffness and aching pain in the shoulder/neck. Conclusions Case definitions which localize upper extremity musculoskeletal disorders to a specific anatomical area may be incomplete. Future clustering studies should rely on both signs and symptoms. Data could be collected from health care providers prospectively to determine the possible prognostic value of the identified clusters with respect to natural history, chronicity, and return to work

A Quantitative and Qualitative Review of Neurocognitive Performance in Pediatric Bipolar Disorder

Bipolar disorder (BD) is an increasingly prevalent diagnosis in youth. As a result, there has been a corresponding increase in interest about neuropsychological and cognitive profiles in children and adolescents diagnosed with BD. Meta-analysis of the existing literature comparing individuals with BD to healthy controls indicated that the largest differences are observed for measures of verbal memory (d = 0.77). Moderate differences were found in the areas of attention (d = 0.62), executive functioning (d = 0.62), working memory (d = 0.60), visual memory (d = 0.51), visual perceptual skills (d = 0.48), and verbal fluency (d = 0.45). Small differences were found for measures of reading (d = 0.40), motor speed (d = 0.33), and full-scale intelligence quotient (IQ) (d = 0.32). Often, few studies have provided relevant information for a particular neurocognitive domain. Despite this, several domains displayed heterogeneity of effect sizes across studies. Methodological factors explained the variance in effect sizes to different extents depending upon the cognitive domain. The changing influence of method artifacts is likely due to variable coverage of cognitive domains across studies and the use of different measures across studies. Findings are consistent with previous meta-analyses of the adult BD neurocognitive literature, suggesting that many of the deficits observed in adults are present earlier in the course of the illness. Study reporting guidelines are offered that may help clarify the impact of illness definitions, mood state, medication status, and other methodological variables on neurocognition in pediatric BD