The effect of repeated concussions on clinical and neurocognitive symptom severity in different contact sports

INTRODUCTION

The potential consequences of repeated concussions in sport are well documented. However, it remains unclear whether the cumulative impact of sports-related concussions differs between different contact sports. Therefore, the aim of the current study was to investigate the cumulative effects of sports-related concussions on clinical and neurocognitive health in different contact sports.

MATERIALS AND METHODS

In a prospective multicenter study, we examined 507 (74 females) active professional athletes between 18 and 40 years of age from five different contact sports (soccer, handball, American football, basketball, and ice hockey). Data collection involved concussion history, clinical symptom evaluation, neurocognitive assessment, and the collection of other sports-related information. Composite scores were built for clinical symptoms (such as neck pain and balance disturbances) and for neurocognitive symptoms (such as memory and attention impairments).

RESULTS

Athletes having suffered 3+ concussions in the past showed disproportionally higher clinical symptom severity than athletes with less than three concussions across all sports. The level of clinical symptom burden in athletes with 3+ concussions indicated mild impairment. The number of past concussions did not affect neurocognitive performance.

DISCUSSION

Repeated sports-related concussions appear to have a cumulative impact on clinical-but not cognitive-symptom severity. Although clinical symptom burden in athletes with 3+ concussions in the past was not alarmingly high yet in our sample, increased caution should be advised at this point. Despite few exceptions, results are similar for different contact sports, suggesting a similar multidisciplinary concussion management across all types of sport.

[Quality standards in treatment and rehabilitation of traumatic brain injuries]

The quality standards of the "Deutsche gesetzliche Unfallversicherung" (DGUV) on the treatment of traumatic brain injuries were first published in 2015. They describe the optimal conditions and requirements of acute treatment and in all phases of rehabilitation and aftercare, according to the current state of knowledge. The aim is to enable a life worth living in family, school, occupation and society for as many injuries as possible. The quality standards, as systematic orientation and decision-making aids, should promote the future development of the treatment and rehabilitation of traumatic brain injuries of all grades of severity and guarantee a uniformly high quality of treatment. A special and comprehensive rehabilitative alignment as well as a close networking of medical and occupation-promoting services will be of particular importance for the institutions participating in the rehabilitation of patients with traumatic brain injuries.

Influence of respiratory motor neurone activity on human autonomic and haemodynamic rhythms

Although humans hold great advantages over other species as subjects for biomedical research, they also bring major disadvantages. One is that among the many rhythmic physiological signals that can be recorded, there is no sure way to know which individual change precedes another, or which change represents cause and which represents effect. In an attempt to deal with the inherent complexity of research conducted in intact human subjects, we developed and used a structural equation model to analyse responses of healthy young men to pharmacological changes of arterial pressure and graded inspiratory resistance, before and after vagomimetic atropine. Our model yielded a good fit of the experimental data, with a system weighted R2 of 0.77, and suggested that our treatments exerted both direct and indirect influences on the variables we measured. Thus, infusions of nitroprusside and phenylephrine exerted all of their direct effects by lowering and raising arterial pressure; the changes of R-R intervals, respiratory sinus arrhythmia and arterial pressure fluctuations that these drugs provoked, were indirect consequences of arterial pressure changes. The only direct effect of increased inspiratory resistance was augmentation of arterial pressure fluctuations. These results may provide a new way to disentangle and understand responses of intact human subjects to experimental forcings. The principal new insight we derived from our modelling is that respiratory gating of vagal-cardiac motor neurone firing is nearly maximal at usual levels of arterial pressure and inspiratory motor neurone activity.

Spinal motoneuron function in lower motor neuron disease: normal corticomotoneuronal and peripheral Ia EPSPs in patients with spinal muscular atrophy

Responses of single tibialis anterior motor units to transcranial magnetic stimulation and to a synchronized Ia volley evoked by peripheral electrical nerve stimulation were obtained in patients with distal spinal muscular atrophy and compared to normal controls. Estimations of excitatory postsynaptic potential (EPSPs) by cross-correlations revealed no difference in rise time of EPSPs for both groups of subjects despite considerable changes in macro-EMG parameters of the motor units studied in patients with spinal muscular atrophy (SMA). The results indicate that voluntarily activated spinal motoneurons in SMA are capable of normal excitatory responses to transcranial magnetic as well as peripheral Ia stimulation.