The wide spectrum of concussion signs is divided in cognitive, affective, somatic and sleep disturbance (Table 7.2). As isolated variables, these factors are not specific for concussion. However, in case of a head trauma, these symptoms are susceptible for the diagnosis of concussion. In case of the presence of loss of consciousness or confusion, the diagnosis of concussion is obvious. When the diagnosis is less certain, a standardised assessment using the Sport Concussion Assessment Tool (SCAT) 2 can aid in the diagnosis (McCrory 2009). The SCAT2 evaluates symptoms, cognitive function and balance. A player with a disturbance of these functions after head trauma can be considered as a patient suffering from concussion. Ideally, it should be performed in the preseason and compared to the athlete’s baseline value. The SCAT2 can be a very helpful tool which is easy to administer. However, it should not be used as a solitary test to diagnose concussion and measure recovery for return-to-play decision. At present there are no accepted grading systems to express concussion severity; the Cantu Scale is an example of a grading system with a long history of use. There is currently no single questionnaire, neuropsychological test, biomarker or additional neuroimaging modality (e.g. functional magnetic resonance brain scanning) to classify a concussion. However, studies in this field are ongoing.

Return to play is a challenging decision. The athlete has to be recovered fully, and symptom evaluation only is not adequate for this decision. A concussed athlete should be monitored multiple times by a physician to evaluate recovery of symptoms, cognitive function and balance. In general, a graduated return-to-play protocol is recommended with an initial brief period of cognitive and physical rest of 2–3 days. As symptoms resolve, a graduated increase in activities can be started with subsequently light aerobic exercise, sports-specific training, training drills without body contact and later on contact in a group and finally return to match playing. According to the Zurich consensus, statement players should be allowed to progress to the next stage when they remain asymptomatic for 24 h after training. If symptoms persist or recur, the player is advised to step back in the protocol. In case of a successful recovery, the player can return to sports within a week. In the majority of cases, full recovery occurs in 7–10 days.

There are several reasons for this conservative programme. It is known that an athlete is at greater risk for further injury when the recovery is not yet fully completed. This injury may be musculoskeletal or a second concussion, due to the decreased reaction time of the athlete. Another consequence of repeat concussions is the chance of developing ‘postconcussion syndrome’. Associations have been postulated between repeat concussions and chronic traumatic encephalopathy and with depression, cognitive impairment and other mental health problems in a small number of athletes. The definition of this postconcussion syndrome is ‘a prolonged symptom duration after concussion’. The exact timeframe for this diagnosis, however, remains unclear according to the variable definitions used in literature (Jotwani and Harmon 2010). The most frequently used cut-off is the presence of more than 3 months of symptoms (Prigatano and Gale 2011). Symptoms persisting from 1 to 6 weeks have been suggested as thresholds for the diagnosis of postconcussion syndrome in athletes. The pathophysiology is not well understood, and hypotheses range from poor coping mechanisms to the occurrence of biomechanical forces on the brainstem, forebrain and temporal lobe. The clinical features can be divided into physical symptoms, emotional changes and cognitive disorders and cover a wide gamut of signs and symptoms. In cases of suspected postconcussion syndrome, the standard additional imaging modalities are applied. Novel modalities, such as functional MRI, are promising and studies are upcoming. The mainstay of the management of this condition is observation and adjustment of activity. Currently, there are no other evidence-based treatments for the sports medicine physician to apply. In older athletes with a history of recurrent concussions, it is known that approximately 10 % will have persisting symptoms of postconcussion syndrome, which further emphasises the need for prevention of recurrent concussions (Prigatano and Gale 2011).