The Pediatric Stroke Outcome Measure: A Validation and Reliability Study
Introduction/Background: The Pediatric Stroke Outcome Measure (PSOM) is appropriate for newborn to adult age for determining stroke-specific outcomes through 115 test items in 5 functional and neurological deficit subscales including: right sensorimotor, left sensorimotor, language production, language comprehension and cognitive/behavior. The PSOM is chronologically organized across the development spectrum. For instance, primitive reflexes are included for children <2 years. Scores for each item range from 0 (no deficit) to 10 (maximum deficit), and are summed to infer the total score. Administration time for this measure is approximately 20 minutes.
Purpose: The purpose of this study was to examine the PSOM’s construct validity in measuring neurological outcomes in pediatric stroke survivors and interrater reliability for both prospective and retrospective scoring. When using this objective measure in a prospective study, one would evaluate a like group of individuals to determine how differing factors affect rates of certain outcomes. Whereas a retrospective study would compare those with a specific impairment following pediatric stroke to those who’ve not been exposed. The study verified the PSOM is valid and reliable for pediatric stroke in both types of studies, but is especially useful in scoring prospective clinical trials.
Methods: Children, newborn to 18 years, diagnosed with arterial ischemic stroke (AIS) or cerebral sinovenous thrombosis (CSVT), at the Hospital for Sick Children (Toronto, CA), from 1994 to 2010 were included in this study. 203 Participants were serially examined with PSOM at 3, 6 and 12 months poststroke and at 2-5 year intervals until the age of 18. QoL and standardized neuropsychological outcomes were assessed in addition to the PSOM. Construct validity (for prospective study) was evaluated against the standardized neurophysiological measures and statistically analyzed through Spearman correlation, linear regression (95% CI), and an alternative chance-corrected statistical test. PSOM scores from medical records were scored by 3 raters and compared with “live” in-clinic PSOM exams completed by those same raters. This information was statistically analyzed to determine both retrospective validity and inter-rater reliability. The range for inter-rater agreement ranged from 0.0-0.2= poor to >0.8= almost perfect.
Results/Limitations/Conclusion: The results indicate PSOM is both valid and reliable for use in children poststroke. These findings are relevant because the PSOM is the only measure of neurological outcomes for this population and is currently being or has been used in many research studies. Construct validity proved to highlight relevant impairments in all 5 subcategories including significant correlation between the cognitive-behavioral subscale and standardized neuropsychological measures of overall intellect, verbal/perceptual reasoning and parental/behavior questionnaires. Additionally, both in-clinic and health record-based scoring was found to have excellent reliability. Some limitations of this study were not all children consented to neuropsychological testing and normally distributed statistics potentially downplayed concerns regarding referral bias. Another shortcoming is that the PSOM is likely to be biased toward motor and sensory deficits over cognitive, language and behavioral impairments. Despite these limitations, the PSOM has proven to be a strong outcome measure, both valid and reliable for prospective and retrospective studies geared towards improving pediatric poststroke outcomes.
Reference
Kitchen L, Westmacott R, Friefeld S, et al. The Pediatric Stroke Outcome Measure. Stroke. 2012;43(6):1602-1608.
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