Long Chain Omega-3 Fatty Acid Intervention in Ageing Adults at Risk of Dementia Following Repeated Head Trauma. Low-level Support or an Opportunity for an Unanswered Question?

Emerging evidence of brain injury on risk of neurodegenerative diseases such as Alzheimer's disease (AD) and chronic traumatic encephalopathy (CTE) have resulted in interest in therapeutic potential of omega-3 fatty acids (n-3FA). We conducted a systematic review of n-3FA therapeutic efficacy for ageing adults at risk of AD/CTE following a history of repeated head trauma. Databases for articles between 1980-June 2020 were examined for studies reporting on n-3 FAs in adults (≥ 45 years) with a history of repeated brain injury. Following an initial screen of 175 articles, 12 studies were considered but were eventually rejected, as they did not meet inclusion criteria. Our review could find no evidence to support, or disprove, effectiveness of n-3FA intervention in older adults with a history of head trauma. With animal studies showing neuro-restorative potential of n-3FA following brain injury, this review highlights the urgent need for human research in this area.

Use of the King-Devick test for the identification of concussion in an amateur domestic women's rugby union team over two competition seasons in New Zealand.

OBJECTIVE: To investigate the use of the King-Devick (K-D) test for sideline assessment of concussive injuries in a New Zealand amateur women's rugby union team. DESIGN: Prospective cohort observational. METHODS: All players were K-D tested during pre-season using a tablet (iPad; Apple Inc., Cupertino, CA). Differences in K-D scores and test-retest reliability were calculated for baseline test scores, baseline, and post-injury (concussion) sideline assessment and baseline and post-season testing scores for tests by year and as a combined score. RESULTS: One training-related (0.3 per 1000 training-hrs) and nine match-related (16.1 per 1000 match-hrs) concussions were recorded. The K-D post-injury (concussion) sideline test score were significantly slower than established baseline (-4.4 [-5.8 to -3.4] s; χ2(1) = 42.2; p < 0.0001; t(9) = -4.0; p = 0.0029; d = -0.8). There was good-to-excellent reliability of the K-D test for baseline (ICC: 0.84 to 0.89), post-injury (concussion) sideline assessment (ICC: 0.82 to 0.97) and post-season evaluation (ICC: 0.79 to 0.83). DISCUSSION: By utilising the baseline to post-injury (concussion) assessment comparisons, any player with a post-injury (concussion) assessment slowing of their K-D test time, regardless of whether the player has, or has not had a witnessed insult, should be withheld from any further participation until they are evaluated by a medical professional trained in the management of concussion. CONCLUSION: This study has provided additional evidence to support the use of the K-D test as a frontline method of assessing concussion with good to excellent reliability of the test for baseline, side-line assessment and post-season evaluation.

Female rugby union injuries in New Zealand: A review of five years (2013-2017) of Accident Compensation Corporation moderate to severe claims and costs.

OBJECTIVES: To provide epidemiological data and related costs for moderate-to-serious and serious injury claims for women's rugby union in New Zealand. DESIGN: A retrospective analytical review of injury entitlement claims for women's rugby from 2013 to 2017. METHODS: Data were analysed by year of competition, age, body site and injury type for total and moderate-to-severe (MSC) Accident Compensation Corporation (ACC) claims and costs. RESULTS: Over 2013 to 2017 there were 26,070 total claims for female rugby union costing $18,440,812 [AD$16,956,998]. The 15-19-year age group recorded 40% (n=1,009) of the total female rugby union Moderate-to-serious and serious (MSC) claims and 41% ($5,419,157 [AD$4,983,112]) of the total female rugby union MSC costs. The knee was the most commonly recorded injury site accounting for 40.3% (n=1,007) of MSC claims and 46.9% ($6,229,714 [AD$5,728732]) of MSC costs with an average cost of $1,245,943 ±$217,796 [AD$595,351 ±AD$104,070] per-year for female rugby union. CONCLUSIONS: This is the first study to report the nature and related costs for moderate-to-serious and serious injury claims for women's rugby union in New Zealand. A total of 26,070 injury claims were lodged over the duration of the study but only 9.6% (n=2,501) of these were classified as MSC injury entitlement claims. Participants 25 years and older accounted for 31% of the female rugby union player claims. Females in the over 35-year age groups compete against younger participants which may account for the higher mean cost per-claim seen as the age groups increase in years until they retire from the game.

I-wave periodicity transcranial magnetic stimulation (iTMS) on corticospinal excitability. A systematic review of the literature.

Repetitive transcranial magnetic stimulation (rTMS) is an established technique that can modulate excitability of the motor cortex and corticospinal tract, beyond the duration of the stimulation itself. More recently, a newer repetitive technique, known as I-wave periodicity TMS (iTMS) has been purported to show increases in corticospinal excitability following at least 10 min of iTMS duration. The aim of this study was to use a systematic review to search the literature from January 2000 to October 2015 with regard to corticospinal outcomes following iTMS intervention. We also rated the quality of studies and assessed the risk of bias by applying the Downs and Black checklist and the Cochrane Collaboration Risk of Bias Tool respectively. From an initial yield of 144, 11 studies were included. Studies were found to be of moderate quality, however a high risk of bias was identified. Despite these issues, evidence from the studies presented in this review so far indicates that iTMS is effective in increasing corticospinal excitability. However, further studies are required from other groups to validate the findings to date. Additional research is required to reduce the variability in corticospinal excitability and also to functional outcomes along with corticospinal excitability following iTMS.

Thomson scattering diagnostic system design for the Compact Toroidal Hybrid experiment.

A new Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The beam, generated by a frequency doubled Continuum PL DLS 2 J Nd:YAG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize the stray laser light that could enter the collection optics. The beam line has been designed with an 8 m propagation distance to the mid-plane of the CTH device with the beam diameter kept less than 3 mm inside the plasma volume. The beam exits the vacuum system through another Brewster window and enters a beam dump, again to minimize the stray light in the vacuum chamber. Light collection, spectral processing, and signal detection are accomplished with an f/#∼ 1 aspheric lens, a commercially available Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. Spectral rejection of stray laser light, if needed, can be performed with the use of an optional interference filter at the spectrometer input. The system has been developed for initial single point measurements of plasmas with core electron temperatures of approximately 20-300 eV and densities of 5 × 10(18) to 5 × 10(19) m(-3) dependent upon operational scenario.

Corticospinal adaptations and strength maintenance in the immobilized arm following 3 weeks unilateral strength training.

Cross-education strength training has being shown to retain strength and muscle thickness in the immobilized contralateral limb. Corticospinal mechanisms have been proposed to underpin this phenomenon; however, no transcranial magnetic stimulation (TMS) data has yet been presented. This study used TMS to measure corticospinal responses following 3 weeks of unilateral arm training on the contralateral, immobilize arm. Participants (n = 28) were randomly divided into either immobilized strength training (Immob + train) immobilized no training (Immob) or control. Participants in the immobilized groups had their nondominant arm rested in a sling, 15 h/day for 3 weeks. The Immob + train group completed unilateral arm curl strength training, while the Immob and control groups did not undertake training. All participants were tested for corticospinal excitability, strength, and muscle thickness of both arms. Immobilization resulted in a group x time significant reduction in strength, muscle thickness and corticospinal excitability for the untrained limb of the Immob group. Conversely, no significant change in strength, muscle thickness, or corticospinal excitability occurred in the untrained limb of the Immob + train group. These results provide the first evidence of corticospinal mechanisms, assessed by TMS, underpinning the use of unilateral strength training to retain strength and muscle thickness following immobilization of the contralateral limb.

Strength training reduces intracortical inhibition.

AIM: Paired-pulse transcranial magnetic stimulation was used to investigate the influence of 4 weeks of heavy load squat strength training on corticospinal excitability and short-interval intracortical inhibition (rectus femoris muscle). METHODS: Participants (n = 12) were randomly allocated to a strength training or control group. The strength training group completed 4 weeks of heavy load squat strength training. Recruitment curves were constructed to determine values for the slope of the curve, V50 and peak height. Short-interval intracortical inhibition was assessed using a subthreshold (0.7 × active motor threshold) conditioning stimulus, followed 3 ms later by a supra-threshold (1.2 × active motor threshold) test stimulus. All motor evoked responses were taken during 10% of maximal voluntary isometric contraction (MVC) torque and normalized to the maximal M-wave. RESULTS: The strength training group attained 87% increases in 1RM squat strength (P < 0.01), significant increases in measures of corticospinal excitability (1.2 × Motor threshold: 116%, P = 0.016; peak height of recruitment curve = 105%, P < 0.001), and a 32% reduction in short-interval intracortical inhibition (P < 0.01) following the 4-week intervention compared with control. There were no changes in any dependent variable (P > 0.05) detected in the control group. CONCLUSION: Repeated high force voluntary muscle activation in the form of short-term strength training reduces short-interval intracortical inhibition. This is consistent with studies involving skilled/complex tasks or novel movement patterns and acute studies investigating acute voluntary contractions.

Leaving the professional tennis circuit: exploratory study of experiences and reactions from elite female athletes.

In 2002, Tennis Australia commissioned a report into the experiences of elite female past players on leaving the professional tennis circuit. Australian players who were in the top 800 of the Women's Tennis Association (WTA) end of year rankings and who had left the professional circuit within the previous 15 years were asked by mail to respond to a questionnaire. The questionnaire asked players to describe their feelings about leaving the tour during the time leading up to leaving the tour to two years after retirement. The main findings of the study suggested that those who planned to leave the tour found the transition process easy, whereas those who did not plan to leave the tour found the process difficult. Most players (66%) did not regret leaving the tour, and, although the remaining players responded that they regretted leaving, none attempted a comeback. Tennis Australia has implemented strategies to assist current players on the professional tour based on the results of this study.

Cigarette smoking, health status, socio-economic status and access to health care in diabetes mellitus: a cross-sectional survey.

BACKGROUND: In diabetes mellitus, cigarette smoking is associated with increased risk of cardiovascular mortality and microvascular complications. We evaluated cigarette smoking in people with diabetes mellitus in a socio-economically deprived area. METHODS: We carried out a cross-sectional survey of people registered with diabetes mellitus at 29 general practices in inner London. Responses were analysed for 1,899 (64%) respondents out of 2,983 eligible. RESULTS: There were 1,899 respondents of whom 968 (51%) had never smoked, 296 (16%) were current smokers and 582 (31%) were ex-smokers. Smoking was more frequent in white Europeans (men 22%, women 20%), than in African Caribbeans (men 15%, women 10%) or Africans (men 8%, women 2%). Smoking prevalence decreased with age. Smokers were more likely to be living in rented accommodation (odds ratio, OR 2.02, 95% confidence interval 1.48 to 2.74). After adjusting for confounding, current smokers had lower SF-36 scores than subjects who had never smoked (mean difference in physical functioning score -5.6, 95% confidence interval -10.0 to -1.2; general health -6.1, -9.7 to -2.5). Current smokers were less likely to have attended a hospital diabetic clinic in the last year (OR 0.59, 0.44 to 0.79), and their hypertension was less likely to be treated (OR 0.47, 0.30 to 0.74). CONCLUSIONS: Compared with non-smokers, smokers had lower socio-economic status and worse health status, but were less likely to be referred to hospital or treated for their hypertension. People with diabetes who smoke can be regarded as a vulnerable group who need more intensive support and treatment.

Functional reorganisation of the corticomotor projection to the hand in skilled racquet players.

While it is known that relatively rapid changes in functional representation may occur in the human sensorimotor cortex in short-term motor-learning studies, there have been few studies of changes in organisation of the corticomotor system associated with the long-term acquisition of motor skills. In the present study, we have used transcranial magnetic stimulation (TMS) to investigate the corticomotor projection to the hand in a group of elite racquet players, who have developed and maintained a high level of skill over a period of many years, and have compared the findings with those in a group of social players and a group of non-playing control subjects. Increased motor-evoked-potential (MEP) amplitudes and shifts in the cortical motor maps for the playing hand were found in all of the elite players and cortical motor thresholds were reduced in some players, whereas in the social players all parameters were within the normal range. The findings in the elite players are interpreted as being indications of a process of functional reorganisation with the motor cortex or corticomotor pathway that are associated with the acquisition and retention of complex motor skills.

The effects of eccentric exercise on neuromuscular function of the biceps brachii.

This study investigated the effects of a bout of exercise-induced muscle damage on strength and motor skill of the elbow flexor muscles. Eight subjects performed 35 maximal isokinetic eccentric elbow flexions at 90 degrees sec(-1) and maximal voluntary contraction (MVC) force, surface electromyography (EMG), plasma creatine kinase (CK) and tracking error associated with a one-dimensional elbow flexion/extension visuomotor pursuit task were studied at intervals up to 28 days after exercise. Subjects showed a post-exercise decline in MVC (mean = 63 +/- 11% (s.d.) of pre-exercise after 1 day, p<0.02) and were still significantly weaker at 21 days. The delayed-onset plasma CK rise and the absence of any quantitative change in surface EMG suggest that the observed weakness was related to muscle fibre damage. Tracking performance decreased in all subjects with the greatest tracking error occurring 1 day post-exercise (mean = 127% +/- 20% of control value, p<0.02). There was a significant negative correlation between strength and tracking performance following exercise (r2 = 0.724). The results demonstrate that performance in activities requiring fine motor control will be impaired for a number of days following a bout of damaging exercise.

The human wedge. A manoeuvre to relieve aortocaval compression during resuscitation in late pregnancy.

The important part of resuscitation in late pregnancy is the relief of aortocaval compression. A manoeuvre to relieve aortocaval compression (the human wedge) is described and evaluated. Eighteen qualified midwives performed basic life support in the supine and wedged position employing the human wedge. Performance was assessed using the Laerdal Resusci Anne Skillmeter. There was no difference (p = 0.4761) in performance of mouth-to-mouth expired air ventilation between the two positions. External cardiac compressions were performed significantly better (p = 0.0005) in the wedged position than in the supine position. The human wedge may provide an alternative to other methods of relieving aortocaval compression.