Identifying Risks for Persistent Postconcussive Symptoms in a Pediatric Emergency Department: An Examination of a Clinical Risk Score.

OBJECTIVE: External examination of a clinical risk score to predict persistent postconcussive symptoms (PPCS) in a pediatric emergency department (ED). METHODS: Prospective cohort study of 5- to 18-year-old patients diagnosed with an acute concussion. Risk factors were collected at diagnosis and participants (n = 85) were followed to determine PPCS 30 days postinjury. Univariate logistic regression analyses were completed to examine associations of risk factors with PPCS. RESULTS: Headache and total clinical risk score were associated with increased odds of PPCS in the univariate analyses, OR 3.37 (95% CI 1.02, 11.10) and OR 1.25 (95% CI 1.02, 1.52), respectively. Additionally, teenage age group, history of prolonged concussions, and risk group trended toward association with PPCS, OR 4.79 (95% CI 0.93, 24.7), OR 3.41 (95% CI 0.88, 13.20), and OR 2.23 (95% CI 0.88, 5.66), respectively. CONCLUSION: Our study supports the use of multiple variables of a clinical risk score to assist with ED risk stratification for pediatric patients at risk for PPCS.

Which symptom assessments and approaches are uniquely appropriate for paediatric concussion?

OBJECTIVE: To (a) identify post-concussion symptom scales appropriate for children and adolescents in sports; (b) review evidence for reliability and validity; and (c) recommend future directions for scale development. DESIGN: Quantitative and qualitative literature review of symptom rating scales appropriate for children and adolescents aged 5 to 22 years. INTERVENTION: Literature identified via search of Medline, Ovid-Medline and PsycInfo databases; review of reference lists in identified articles; querying sports concussion specialists. 29 articles met study inclusion criteria. RESULTS: 5 symptom scales examined in 11 studies for ages 5-12 years and in 25 studies for ages 13-22. 10 of 11 studies for 5-12-year-olds presented validity evidence for three scales; 7 studies provided reliability evidence for two scales; 7 studies used serial administrations but no reliable change metrics. Two scales included parent-reports and one included a teacher report. 24 of 25 studies for 13-22 year-olds presented validity evidence for five measures; seven studies provided reliability evidence for four measures with 18 studies including serial administrations and two examining Reliable Change. CONCLUSIONS: Psychometric evidence for symptom scales is stronger for adolescents than for younger children. Most scales provide evidence of concurrent validity, discriminating concussed and non-concussed groups. Few report reliability and evidence for validity is narrow. Two measures include parent/teacher reports. Few scales examine reliable change statistics, limiting interpretability of temporal changes. Future studies are needed to fully define symptom scale psychometric properties with the greatest need in younger student-athletes.

Impact of cognitive reserve on the relationship of lead exposure and neurobehavioral performance.

BACKGROUND: Cognitive reserve (CR)--a construct studied in many neurologic disorders--refers to the maintenance of cognitive performance in spite of ongoing underlying brain pathology. OBJECTIVE: We hypothesized that a dose-effect relationship would exist between chronic occupational lead exposure and cognitive effects in workers with low CR but not in workers with high CR and identical lead exposure, and that level of CR would not influence the relationship between lead exposure and motor performance. METHODS: We stratified currently employed lead smelter workers by Wide Range Achievement Test-R for reading (WRAT), a recognized measure of CR, into loCR and hiCR groups. From these two groups we matched 56 pairs on working lifetime weighted blood lead (TWA). We performed a factor analysis on 14 neuropsychological outcome variables. Within each CR group regression analyses after adjusting for age, alcohol use, and depression scale score tested for dose-effect relationships between TWA and outcome variables. RESULTS: Both CR groups had comparable age, years employed, alcohol use, and current blood lead levels. Factor analysis provided three factors and five tests used in the regression analyses. Significant dose-effect relationships between TWA and cognitive tests present only in the loCR group included Attention Factor and Digit Symbol. Both CR groups demonstrated significant dose-effect relationships on the Motor Factor. CONCLUSION: This study found that cognitive reserve protects against the effect of chronic lead exposure on select measures of cognitive performance but not on motor performance.

Differential effects of lead exposure on components of verbal memory.

AIMS: To determine if verbal learning and memory requiring acquisition and retention of information is differentially affected by lead exposure. METHODS: The Rey Auditory Verbal Learning Test (RAVLT), a test of verbal learning and memory, was administered to 256 English speaking lead smelter workers who had a mean (SD) age of 41 (9.4) years and employment duration of 17 (8.1) years. Lead exposure variables, based on up to 25 years of prior blood lead data, included a mean (SD) current blood lead (PbB) of 28 (8.8) microg/dl, working lifetime time weighted average blood lead (TWA) of 39 (12.3) microg/dl, and working lifetime integrated blood lead index (IBL) of 728 (434.4) microg-y/dl. Associations of these chronic and recent lead exposure variables with measures from the RAVLT were modelled through multiple linear regressions after controlling for age and educational achievement. RESULTS: PbB was not associated with any of the RAVLT variables. However, TWA and IBL contributed significantly to the explanation of variance of measures of encoding/storage and retrieval but not to immediate memory span, attention, and learning. Grouping study participants by RAVLT performance according to three recognised clinical memory paradigms showed significantly higher TWA and IBL in the group with "generalised memory impairment" after adjusting for age and educational achievement. We examined recall mechanisms in each group by serial position in the word list and found stronger primacy (recall of words from the beginning of the list) in the "no impairment" and "retrieval difficulties" groups while the "generalised memory impairment" group had better performance on recency (recall of words from the end of the list). CONCLUSIONS: Lead exposure over years and not PbB interfered with the organisation and recall of previously learned verbal material. Chronic lead exposure affects encoding/storage and retrieval of verbal information.

The decomposition of acidic and neutral cannabinoids in organic solvents.

High-pressure liquid chromatography was used to study (a) the relative efficiencies of methanol, chloroform, light petroleum (B.P. 40-60 degrees) and methanol-chloroform (9:1) for extracting neutral and acidic cannabinoids from cannabis resin; (b) the decomposition patterns of the resulting solutions under various storage conditions, and (c) the cannabinoid profile of a cross section through a block of cannabis resin. The results show that (a) methanol is the most effective extracting solvent of those tested; (b) acidic cannabinoids in solution decompose in darkness by varying amounts depending on the temperature, solvent, storage time and particular cannabinoid; (c) neutral cannabinoids in solution are relatively stable in darkness; (d) daylight causes appreciable decomposition of both acidic and neutral cannabinoids in solution, (e) the cannabinoid profile of a resin is complex with lower levels of acidic material in the outer layers.

High-pressure liquid chromatography of cannabis. Quantitative analysis of acidic and neutral cannabinoids.

A reversed-phase high-pressure liquid chromatographic method has been developed for the simultaneous analysis of the acidic and neutral cannabinoids in cannabis. Cannabigerol and cannabigerolic acid have been located in the liquid chromatogram of cannabis and factors affecting the chromatographic process are discussed. A method for quantitating one component in the presence of a second unresolved component is described.