Chantel T. Debert

Robotic assessment of sensorimotor deficits after traumatic brain injury.

Background and Purpose: Robotic technology is commonly used to quantify aspects of typical sensorimotor function. We evaluated the feasibility of using robotic technology to assess visuomotor and position sense impairments following traumatic brain injury (TBI). We present results of robotic sensorimotor function testing in 12 subjects with TBI, who had a range of initial severities (9 severe, 2 moderate, 1 mild), and contrast these results with those of clinical tests. We also compared these with robotic test outcomes in persons without disability. Methods: For each subject with TBI, a review of the initial injury and neuroradiologic findings was conducted. Following this, each subject completed a number of standardized clinical measures (Fugl-Meyer Assessment, Purdue Peg Board, Montreal Cognitive Assessment, Rancho Los Amigos Scale), followed by two robotic tasks. A visually guided reaching task was performed to assess visuomotor control of the upper limb. An arm position-matching task was used to assess position sense. Robotic task performance in the subjects with TBI was compared with findings in a cohort of 170 person without disabilities. Results: Subjects with TBI demonstrated a broad range of sensory and motor deficits on robotic testing. Notably, several subjects with TBI displayed significant deficits in one or both of the robotic tasks, despite normal scores on traditional clinical motor and cognitive assessment measures. Discussion and Conclusions: The findings demonstrate the potential of robotic assessments for identifying deficits in visuomotor control and position sense following TBI. Improved identification of neurologic impairments following TBI may ultimately enhance rehabilitation.

Role of advanced neuroimaging, fluid biomarkers and genetic testing in the assessment of sport-related concussion: a systematic review

Objective To conduct a systematic review of published literature on advanced neuroimaging, fluid biomarkers and genetic testing in the assessment of sport-related concussion (SRC). Data sources Computerised searches of Medline, PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, Scopus and Cochrane Library from 1 January 2000 to 31 December 2016 were done. There were 3222 articles identified. Study selection In addition to medical subject heading terms, a study was included if (1) published in English, (2) represented original research, (3) involved human research, (4) pertained to SRC and (5) involved data from neuroimaging, fluid biomarkers or genetic testing collected within 6 months of injury. Ninety-eight studies qualified for review (76 neuroimaging, 16 biomarkers and 6 genetic testing). Data extraction Separate reviews were conducted for neuroimaging, biomarkers and genetic testing. A standardised data extraction tool was used to document study design, population, tests employed and key findings. Reviewers used a modified quality assessment of studies of diagnostic accuracy studies (QUADAS-2) tool to rate the risk of bias, and a modified Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to rate the overall level of evidence for each search. Data synthesis Results from the three respective reviews are compiled in separate tables and an interpretive summary of the findings is provided. Conclusions Advanced neuroimaging, fluid biomarkers and genetic testing are important research tools, but require further validation to determine their ultimate clinical utility in the evaluation of SRC. Future research efforts should address current gaps that limit clinical translation. Ultimately, research on neurobiological and genetic aspects of SRC is predicted to have major translational significance to evidence-based approaches to clinical management of SRC, much like applied clinical research has had over the past 20 years.

Dietary and metabolic differences in pre- versus postmenopausal women taking or not taking hormone replacement therapy

While hormonal fluctuations during the menstrual cycle are known to affect energy intake, changes in dietary intake at menopause and specifically with hormone replacement therapy (HRT) are less well understood. Our objective was to assess dietary macro- and micronutrient intakes in premenopausal women (PEMW) in the luteal and follicular phases and postmenopausal women (PSMW) taking or not taking HRT. Serum estradiol and progesterone as well as resting energy expenditure (REE) and respiratory exchange ratio (RER) were measured. In the 9 PEMW, daily energy intake was 19% higher during the luteal versus follicular phase (2089+/-178 vs. 1752+/-158 kcal/day, p<0.05). The luteal phase was characterized by higher intake of total and saturated fat and a lower micronutrient density. In the 7 PSMW not taking HRT and 6 women taking HRT, there was no significant difference in total energy or macronutrient intake. Neither PEMW nor PSMW met national nutritional recommendations for folate, vitamin D, vitamin E and calcium. Serum progesterone levels were positively correlated with protein intake and negatively correlated with percent carbohydrate in the diet. REE was lower (p<0.05) in PSMW not taking HRT, but not in those taking HRT compared to young women. We confirm increased energy intake in the luteal phase in PEMW but found no difference in energy intake between PSMW taking or not taking HRT. While the quality of the diet in PSMW women was closer to national nutritional recommendations, several at risk nutrients that have been linked to health and disease were found in both groups.

Nonstationary multivariate modeling of cerebral autoregulation during hypercapnia

We examined the time-varying characteristics of cerebral autoregulation and hemodynamics during a step hypercapnic stimulus by using recursively estimated multivariate (two-input) models which quantify the dynamic effects of mean arterial blood pressure (ABP) and end-tidal CO2 tension (PETCO2) on middle cerebral artery blood flow velocity (CBFV). Beat-to-beat values of ABP and CBFV, as well as breath-to-breath values of PETCO2 during baseline and sustained euoxic hypercapnia were obtained in 8 female subjects. The multiple-input, single-output models used were based on the Laguerre expansion technique, and their parameters were updated using recursive least squares with multiple forgetting factors. The results reveal the presence of nonstationarities that confirm previously reported effects of hypercapnia on autoregulation, i.e. a decrease in the MABP phase lead, and suggest that the incorporation of PETCO2 as an additional model input yields less time-varying estimates of dynamic pressure autoregulation obtained from single-input (ABP-CBFV) models.

Knowing what we don't know: long-term psychiatric outcomes following adult concussion in sports

Objective: Amidst a growing concern regarding concussion in sports, there is an emerging link between sport concussion and mental health outcomes. This review summarizes the current literature addressing long-term psychiatric sequelae associated with sport concussion in adults. Method: Several databases were searched using a broad list of keywords for each of concussion, sports, and mental health, with a resultant 311 studies for initial review. After limiting studies based on duplication, appropriateness of data, and relevance, 21 studies remained pertaining to depression, anxiety, substance use, and behavioural changes, including those highlighting chronic traumatic encephalopathy (CTE). Results: Most studies identified suggested an increased prevalence of depressive symptoms related to concussion history. A conference abstract and qualitative study suggested increasing anxiety related to concussion history; however, a PhD dissertation found no relationship. In reviewing substance use, several studies mentioned use in athletes suspected of having concussion histories, although no link was established, while another noted undiagnosed concussion as leading to current substance misuse. Regarding behavioural changes, all studies identified occurrences of behaviour and/or cognitive changes in participants, with 2 studies suggesting a link with concussion history. With respect to CTE, concerns with mood, behaviour, cognition, and substance use were consistently highlighted, suggesting relations to previous sport concussion; however, the notion of different CTE subtypes and clear aetiology behind concussion severity or frequency was not consistently elucidated. Conclusion: There appears to be a growing body of evidence supporting the presence of long-term psychiatric and psychological sequelae following sport concussion in adults.

Differences between middle cerebral artery blood velocity waveforms of young and postmenopausal women.

Objective: We characterized middle cerebral artery (MCA) blood flow velocity waveforms measured by transcranial Doppler ultrasonography in premenopausal (26.6 ± 6.1 years, mean ± SD) and postmenopausal (54.0 ± 3.6 years) women, of whom six were receiving hormone therapy (PM-HT) and seven were not (PM-non-HT). We hypothesized that feature points on MCA waveforms are altered in postmenopausal women compared with those in young women. Design: A short protocol involved maintaining end-tidal PO2 at euoxia (88 mm Hg) and end-tidal PCO2 at 1.5 mm Hg above eucapnic values using a dynamic end-tidal forcing system. Doppler data for the velocity spectral outline (Vp) were collected every 10 ms, and velocity waveform analyses were done on a beat-by-beat basis. Waveform features were identified over each cardiac cycle, including the average Vp (VCYC), maximum acceleration (AMAX), and the ratio of the velocity at the reflected wave and the velocity at peak systole (VR:VMAX). Results: VCYC was unchanged between premenopausal and postmenopausal women (69.4 ± 9.6 and 67.5 ± 11.1 cm/s, respectively). AMAX was significantly higher (P = 0.007) in premenopausal women (987.9 ± 280.7 cm/s2) compared with postmenopausal women (743.1 ± 100.3). Conversely, VR:VMAX was significantly smaller (P < 0.001) in premenopausal women (0.90 ± 0.09) compared with postmenopausal women (1.11 ± 0.05). In postmenopausal women, the reflected wave is higher than the maximum velocity at peak systole, suggesting the presence of a shoulder in the MCA waveform. Conclusions: Further investigations are required to assess whether this waveform analysis can provide insight into pathophysiologic changes in cerebral hemodynamics with aging.

Neuroendocrine Dysfunction in a Young Athlete With Concussion: A Case Report.

An 18-year-old female ringette and basketball player presented to our sport concussion clinic 27 months after concussion with fatigue, headache, exercise intolerance, polyuria, nocturia, and difficulties concentrating. Her history was remarkable for 4 previous concussions. Her neurologic examination was normal. Neuroendocrine screen including thyroid function, morning cortisol, glucose, and insulin-like growth factor-1 (screening test for growth hormone deficiency) were normal. Further testing for growth hormone deficiency with an insulin hypoglycemia test revealed severe growth hormone deficiency. Urine and serum electrolytes were borderline normal, suggesting partial diabetes insipidus. Treatments with growth hormone replacement lead to complete recovery. This case highlights the importance of maintaining a high index of suspicion for neuroendocrine abnormalities in athletes with persistent symptoms after sport concussion. Symptoms can be nonspecific and go undiagnosed for years, but appropriate recognition and treatment can restore function.

Effects of ovarian hormones and aging on respiratory sinus arrhythmia and breathing patterns in women

We investigated the effect of ovarian hormones and aging on breathing pattern [pulmonary minute ventilation

Using Robotics to Quantify Impairments in Sensorimotor Ability, Visuospatial Attention, Working Memory, and Executive Function After Traumatic Brain Injury

{\left( {\dot {V}_{{{\rm E}}}} \right)}