Exploring individual fixel-based white matter abnormalities in epilepsy

Diffusion MRI has provided insight into the widespread structural connectivity changes that characterize epilepsies. Although syndrome-specific white matter abnormalities have been demonstrated, studies to date have predominantly relied on statistical comparisons between patient and control groups. For diffusion MRI techniques to be of clinical value, they should be able to detect white matter microstructural changes in individual patients. In this study, we apply an individualized approach to a technique known as fixel-based analysis, to examine fibre-tract-specific abnormalities in individuals with epilepsy. We explore the potential clinical value of this individualized fixel-based approach in epilepsy patients with differing syndromic diagnoses. Diffusion MRI data from 90 neurologically healthy control participants and 10 patients with epilepsy (temporal lobe epilepsy, progressive myoclonus epilepsy, and Dravet Syndrome, malformations of cortical development) were included in this study. Measures of fibre density and cross-section were extracted for all participants across brain white matter fixels, and mean values were computed within select tracts-of-interest. Scanner harmonized and normalized data were then used to compute Z-scores for individual patients with epilepsy. White matter abnormalities were observed in distinct patterns in individual patients with epilepsy, both at the tract and fixel level. For patients with specific epilepsy syndromes, the detected white matter abnormalities were in line with expected syndrome-specific clinical phenotypes. In patients with lesional epilepsies (e.g. hippocampal sclerosis, periventricular nodular heterotopia, and bottom-of-sulcus dysplasia), white matter abnormalities were spatially concordant with lesion location. This proof-of-principle study demonstrates the clinical potential of translating advanced diffusion MRI methodology to individual-patient-level use in epilepsy. This technique could be useful both in aiding diagnosis of specific epilepsy syndromes, and in localizing structural abnormalities, and is readily amenable to other neurological disorders. We have included code and data for this study so that individualized white matter changes can be explored robustly in larger cohorts in future work.

TDS Similarity: Outlier Analysis Using a Similarity Index to Compare Time-Series Responses of Temporal Dominance of Sensations Tasks

Temporal dominance of sensations (TDS) methods are used to record temporally developing sensations while eating food samples. Results of TDS tasks are typically discussed using averages across multiple trials and panels, and few methods have been developed to analyze differences between individual trials. We defined a similarity index between two time-series responses of TDS tasks. This index adopts a dynamic level to determine the importance of the timing of attribute selection. With a small dynamic level, the index focuses on the duration for attributes to be selected rather than on the timing of the attribute selection. With a large dynamic level, the index focuses on the temporal similarity between two TDS tasks. We performed an outlier analysis based on the developed similarity index using the results of TDS tasks performed in an earlier study. Certain samples were categorized as outliers irrespective of the dynamic level, whereas the categorization of a few samples depended on the level. The similarity index developed in this study achieved individual analyses of TDS tasks, including outlier detection, and adds new analysis techniques to TDS methods.

Esterase, Glutathione S-Transferase and NADPH-Cytochrome P450 Reductase Activity Evaluation in Cacopsylla pyri L. (Hemiptera: Psyllidae) Individual Adults

Cacopsylla pyri (L.) (Hemiptera: Psyllidae) is a key pest of pear orchards in Spain. The large number of insecticide treatments necessary for control may be an important contributor to the emergence of resistance. Laboratory toxicity and biochemical assays are necessary to validate the existence of insecticide resistance and establish the underlying mechanisms. All the methodologies developed to evaluate enzyme activity in C. pyri to date have incorporated "pools" of adults to detect minimum activity ranges. In this study, we determined the optimal working conditions for evaluation of the activities of esterase, glutathione S-transferase and NADPH-cytochrome P450 reductase in individual insects via colorimetric methods using a microplate reader. The main factors affecting enzymatic analysis activity, such as enzyme source and substrate concentration, filter wavelength, buffer pH, reaction time and additives, were evaluated for optimization. Determining the frequency of resistant individuals within a population could be used as an indicator for the evolution of insecticide resistance over time. Two laboratory strains, one of them selected with cypermethrin, and two field populations were analyzed for this purpose. The data obtained revealed high values and great variation in the activity ranges of esterase (EST) in the insecticide-selected population as well as in the field populations validating the applied methodology.

Proteomics-Based Identification of Diagnostic Biomarkers Related to Risk Factors and Pathogenesis of Ischemic Stroke

Ischemic stroke is caused by blood clot formation and consequent vessel blockage. Proteomic approaches provide a cost-effective alternative to current diagnostic methods, including computerized tomography (CT) scans and magnetic resonance imaging (MRI). To identify diagnostic biomarkers associated with ischemic stroke risk factors, we performed individual proteomic analysis of serum taken from 20 healthy controls and 20 ischemic stroke patients. We then performed SWATH analysis, a data-independent method, to assess quantitative changes in protein expression between the two experimental conditions. Our analysis identified several candidate protein biomarkers, 11 of which were validated by multiple reaction monitoring (MRM) analysis as novel diagnostic biomarkers associated with ischemic stroke risk factors. Our study identifies new biomarkers associated with the risk factors and pathogenesis of ischemic stroke which, to the best of our knowledge, were previously unknown. These markers may be effective in not only the diagnosis but also the prevention and management of ischemic stroke.

Recovery progression and symptom resolution in sport-related mild traumatic brain injury

OBJECTIVE

To characterize the recovery progression of a group of athletes who participated in a concussion management program based on (1) group analysis and (2) individual analysis.

SETTING

Concussion management clinic.

PARTICIPANTS

Thirty athletes (22 males, 8 females; baseline age = 16.23 ± 2.40 years) who had undergone four assessments: one baseline and three post-injury assessments at 3, 8, 15 days post-injury.

DESIGN

Retrospective clinical.

MAIN MEASURES

Four neurocognitive scores of the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) including verbal memory, visual memory, speed of processing and reaction time and also a total symptom score.

RESULTS

Group-analysis showed a clear decline in verbal memory (F(3, 87) = 7.36, p < 0.000) and an increase in self-reported symptoms (χ²(3, N = 30) = 48.703, p < 0.000), 3 days post-injury. By day 8, athletes had returned to their baseline levels for verbal memory and were not experiencing symptoms. When athletes' scores were examined individually, at 3 days post-injury, 60% of the athletes showed deficits on two or more of the ImPACT variables. This rate dropped to 23% at 8 days post-injury and remained the same (23%) 15 days post-injury.

CONCLUSIONS

In concussion recovery, variability is the rule, rather than the exception, with regard to both impaired neurocognitive functions and recovery duration.

Measurement Issues: Large effect sizes do not mean most people get better - clinical significance and the importance of individual results

BACKGROUND

This paper seeks to compare group statistical analysis with effect size, group measures of clinical significance (Reliable Change Index and normative comparison), and individual analysis of clinical significance.

METHOD

Measures of variables important to parenting and child behavior improvement (Parenting Scale, Eyberg Child Behavior Inventory, and Parenting Stress Index [PSI]) were administered pre and post for a 9- to 10-week group Behavioral Parent Training Intervention. Analysis compares traditional group statistical significance testing with group measure of clinical significance and individual analysis of clinical significance.

RESULTS

All three measures demonstrated statistically significant differences from pre to post, with large effect sizes. Group measures of clinical significance, however, demonstrated meaningful change only on the PSI, while individual analysis showed improvements of 54% of participants at best and 0% at worst.

CONCLUSIONS

Individual analysis of clinical significance provides valuable information in treatment outcomes and should be included as a standard practice in outcomes research.