Comparison of respiratory parameters in participants with and without chronic low back pain.

BACKGROUND: Individuals with chronic low back pain (CLBP) may lack coordination between the stabilising and respiratory functions of trunk muscles. The trunk stabilisers compromise breathing to maintain spinal stability, leading to breathing dysfunctions. Maximal voluntary ventilation (MVV) is indicative of the respiratory muscle endurance and strength whereas end-tidal carbon dioxide (PETCO2) gives an estimate of breathing patterns that closely reflect the arterial measurement of CO2. CLBP has been shown to have a significant effect on respiratory functions. However, the impact has not yet been quantified. Further, there is a dearth of literature comparingrespiratory functions between CLBP and healthy individuals. This study investigates respiratory functions in participants with and without CLBP. METHODS: The study compared the respiratory functions of maximal voluntary ventilation (MVV) and End-Tidal Carbon Dioxide (PETCO2) between 14 participants with CLBP and 14 healthy individuals. Participants in both groups were matched for age, height, weight and body surface area. The assessment of MVV and PETCO2 were performed sitting, standing on a stable surface, and on an unstable surface (BOSU ball). RESULTS: The mean of measured MVV (L/min) was found to be lower (p < 0.05) in the CLBP group when compared to the healthy group. Mean PETCO2 and respiratory rate was found to be higher in CLBP group when compared to the healthy group in all three positions, although this was not found to be statistically significant. CONCLUSION: The findings of this study demonstrated sub-optimal respiratory parameters in participants with chronic low back pain. However, when adjusted for gender, the difference was not found to be significant between the two groups.

Prevalence and predictors of seizure clusters: A prospective observational study of adult patients with epilepsy.

OBJECTIVE: The purpose of this prospective observational study was to describe the prevalence and adverse outcomes associated with seizure clusters (defined as ≥2 seizures in a 6-hour period) in a large sample of adult patients with a range of epilepsy severities and to identify clinical characteristics predictive of clustering. METHODS: Patients maintained a seizure diary and were contacted monthly to verify compliance and data accuracy. Logistic regression models were utilized to test associations between individual patient demographic/clinical characteristics and seizure clustering. Fisher's exact test was utilized to test associations between rescue medication use and adverse seizure-related outcomes. RESULTS: A total of 300 patients were followed prospectively for one year; 247 patients qualified for final analysis. Six-hour seizure clusters occurred in 45.8% of patients with active epilepsy at enrollment, including 62.7% of those with prior day-clusters and 30.0% of those without prior day-clusters. The odds of clustering were markedly greater among patients who reported a higher seizure frequency (>4 seizures per year vs. 1-4 seizures per year) (adjusted odds ratio (OR): 8.9; 95% confidence interval (CI): 3.2-24.6; p < 0.0001) and among patients with prior day-clusters (adjusted OR: 11.0; 95% CI: 1.2-104.2; p = 0.036). Rescue medication use was associated with significantly fewer injuries and emergency department visits, but rescue medication was underutilized. CONCLUSIONS: Seizure clusters are common, occurring in nearly half of adult patients with active epilepsy followed prospectively over one year, and are more frequent in those with higher seizure frequencies and prior day-clusters. Although underutilized, rescue medication was associated with fewer injuries and emergency department visit.

Impaired consciousness in partial seizures is bimodally distributed.

OBJECTIVE: To investigate whether impaired consciousness in partial seizures can usually be attributed to specific deficits in the content of consciousness or to a more general decrease in the overall level of consciousness. METHODS: Prospective testing during partial seizures was performed in patients with epilepsy using the Responsiveness in Epilepsy Scale (n = 83 partial seizures, 30 patients). Results were compared with responsiveness scores in a cohort of patients with severe traumatic brain injury evaluated with the JFK Coma Recovery Scale-Revised (n = 552 test administrations, 184 patients). RESULTS: Standardized testing during partial seizures reveals a bimodal scoring distribution, such that most patients were either fully impaired or relatively spared in their ability to respond on multiple cognitive tests. Seizures with impaired performance on initial test items remained consistently impaired on subsequent items, while other seizures showed spared performance throughout. In the comparison group, we found that scores of patients with brain injury were more evenly distributed across the full range in severity of impairment. CONCLUSIONS: Partial seizures can often be cleanly separated into those with vs without overall impaired responsiveness. Results from similar testing in a comparison group of patients with brain injury suggest that the bimodal nature of Responsiveness in Epilepsy Scale scores is not a result of scale bias but may be a finding unique to partial seizures. These findings support a model in which seizures either propagate or do not propagate to key structures that regulate overall arousal and thalamocortical function. Future investigations are needed to relate these behavioral findings to the physiology underlying impaired consciousness in partial seizures.

Prospective assessment of ictal behavior using the revised Responsiveness in Epilepsy Scale (RES-II).

Impaired consciousness in epilepsy has a significant negative impact on patients' quality of life yet is difficult to study objectively. Here, we develop an improved prospective Responsiveness in Epilepsy Scale-II (RES-II) and report initial results compared with the earlier version of the scale (RES). The RES-II is simpler to administer and includes both verbal and non-verbal test items. We evaluated 75 seizures (24 patients) with RES and 34 seizures (11 patients) with RES-II based on video-EEG review. The error rate per seizure by test administrators improved markedly from a mean of 2.01 ± 0.04 with RES to 0.24 ± 0.11 with RES-II. Performance during focal seizures showed a bimodal distribution, corresponding to the traditional complex partial vs. simple partial seizure classification. We conclude that RES-II has improved accuracy and testing efficiency compared with the original RES. Prospective objective testing will ultimately lead to a better understanding of the mechanisms of impaired consciousness in epilepsy.