Symptom-based assessment of the severity of a concussion

OBJECT: Current grading systems of concussion and return-to-play guidelines have little empirical support. The authors therefore examined the relationships of the characteristics and symptoms of concussion and the history of concussion to three indicators of concussion severity-number of immediate symptoms, number of symptoms at the initial follow-up examination, and duration of symptoms--to establish an empirical basis for grading concussions. METHODS: Forty-seven athletes who sustained concussions were administered alternate forms of an Internet-based neurocognitive test until their performances were within normal limits relative to baseline levels. Assessments of observer-reported and self-reported symptoms at the sideline of the playing field on the day of injury, and at follow-up examinations were also obtained as part of a comprehensive concussion management protocol. Although loss of consciousness (LOC) was a useful indicator of the initial severity of the injury, it did not correlate with other indices of concussion severity, including duration of symptoms. Athletes reporting memory problems at follow-up examinations had significantly more symptoms in general, longer durations of those symptoms, and significant decreases in scores on neurocognitive tests administered approximately 48 hours postinjury. This decline of scores on neurocognitive testing was significantly associated with an increased duration of symptoms. A history of concussion was unrelated to the number and duration of symptoms. CONCLUSIONS: This paper represents the first documentation of empirically derived indicators of the clinical course of postconcussion symptom resolution. Self-reported memory problems apparent 24 hours postconcussion were robust indicators of the severity of sports-related concussion and should be a primary consideration in determining an athlete's readiness to return to competition. A decline on neurocognitive testing was the only objective measure significantly related to the duration of symptoms. Neither a brief LOC nor a history of concussion was a useful predictor of the duration of postconcussion symptoms.     

Experimental cerebral concussion

The activity of mitochondrial enzymes (succinic dehydrogenase and cytochrome oxidase) and enzymes associated with blood-brain barrier function (butyrylcholinesterase and alkaline phosphatase) in the CNS of rats was studied from 5 minutes to 62 hours after cerebral concussion. There was a transient increase in succinic dehydrogenase activity during the first hour after concussion in the neurons of the structures close to the impact. The alkaline phosphatase activity, strongly positive in the walls of normal blood vessels, decreased within five minutes after concussion; it virtually disappeared in 15 minutes but returned to normal level after 62 hours. These findings are in good correlation with previous electron microscopic observations. Their significance is discussed.     

Spinal cord concussion

A reliable experimental model using decerebrate frogs has been developed by which a measured cutaneous stimulus to the right forelimb produces a single electrical response from the left sciatic nerve. Using this model, the minimal concussing force necessary to abolish the propagation of the nerve impulse down the spinal cord was established by trial and error. The mean recovery time was 31.2 seconds, with a standard deviation of 1.32 seconds. Recovery of function of the spinal cord, as measured by this method, was complete following single and multiple concussions.     

Spinal cord concussion

The hallmark of concussion injuries of the nervous system is the rapid and complete resolution of neurological deficits. Cerebral concussion has been well studied, both clinically and experimentally. In comparison, spinal cord concussion (SCC) is poorly understood. The clinical and radiological features of 19 SCC injuries in the general population are presented. Spinal cord injuries were classified as concussions if they met three criteria: 1) spinal trauma immediately preceded the onset of neurological deficits; 2) neurological deficits were consistent with spinal cord involvement at the level of injury; and 3) complete neurological recovery occurred within 72 hours after injury. Most cases involved young males, injured during athletics or due to falls. Concussion occurred at the two most unstable spinal regions, 16 involving the cervical spinal and three the thoracolumbar junction. Fifteen cases presented with combined sensorimotor deficits, while four exhibited only sensory disturbances. Many patients showed signs of recovery with the first few hours after injury and most had completely recovered within 24 hours. Only one case involved an unstable spinal injury. There was no evidence of ligamentous instability, spinal stenosis, or canal encroachment in the remaining 18 cases. Two patients, both children, suffered recurrent SCC injuries. No delayed deterioration or permanent cord injuries occurred. Spinal abnormalities that would predispose the spinal cord to a compressive injury were present in only one of the 19 cases. This suggests that, as opposed to direct cord compression, SCC may be the result of an indirect cord injury. Possible mechanisms are discussed.     

The seat and the nature of concussion

Summary The primary object of this paper is to enquire whether or not there occurs a cerebral lesion of uniform size and shape in a constant position to account for the state of post traumatic unconsciousness. As an introduction the possible seats of consciousness are reviewed and the neural mechanisms concerned briefly discussed. The upper brain stem area, the hemispheral cortical and their connecting fibres are each in turn considered as the possible seats of concussion. Also whether the damage is primary, neuronal, glial, reticular or vascular is discussed. One conclusion is that probably there are as many varieties of causative lesion as there are degrees and types of unconsciousness.

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Zusammenfassung Die Arbeit befaßt sich in erster Linie mit der Frage, ob oder ob nicht Hirnläsionen von gleicher Art, Ausmaß und Lokalisation für die posttraumatische Bewußtlosigkeit verantwortlich sind.Einleitend wird ein Überblick über die möglichen lokalisatorischen Representationen der Bewußtseinsfunktion gegeben und der zugehörige neurale Mechanismus kurz besprochen. Die Gebiete des oberen Hirnstammes wie auch die Groß-hirnrinde und ihre Bahnenverbindungen können als möglicher Sitz der Bewußtseinsfunktionen betrachtet werden. Es wird weiter diskutiert, ob die Schädigung primär an den Neuronen, der Glia, dem retikulären System oder dem Gefäßsystem angreift. Eine der Folgerungen ist, daß es wahrscheinlich ebenso viele Varianten der ursächlichen Läsion wie Grade und Arten der Bewußtseinsstörungen gibt.

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Resumen El primer objeto de este articulo es investigar si sobreviene o nó una lesión cerebral de importancia y de aspecto uniforme y en una posición constante para explicar el estado de pérdida de conciencia traumático.Como introducción se revisan los lugares posibles que intervienen en la pérdida de conciencia y también se discuten brevemente los mecanismos neurógenos.Se consideran a su vez el tronco cerebral, la corteza hemisférica y sus fibras de conexión como lugares posibles de contusión.También se discute si la lesión primaria es neuronal, glial, reticular o vascular. Se concluye que como hay un gran número de variedades de lesión causal asimismo existen diferentes grados y tipos de pérdida de conciencia.

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Résumé Le premier objet de cet article est de rechercher s'il survient ou non une lésion cérébrale d'importance et d'aspect uniforme dans une position constante pour expliquer l'état de perte de connaissance traumatique.En introduction, les sièges possibles de perte de conscience sont passés en revue et les mécanismes neurogènes intéressés sont brièvement discutés.Les aires supérieures du tronc cérébral, la corticalité hémisphérique et leurs fibres de connexion sont, chacune à son tour, considérées comme les sièges possibles de contusion.Il est aussi discuté si le dommage primaire est neuronal, glial, réticulé ou vasculaire.La conclusion est qu'il existe autant de variétés de lésions causales, qu'il y a de degrés et de types de perte de connaissance.

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Riassunto Scopo di questo lavoro è quello di indagare se è necessaria o meno una lesione cerebrale di grandezza e profondità uniforme in una regione costante per provocare una perdita di coscienza post-traumatica. La parte superiore del tronco, la corteccia emisferica e le loro fibre di connessione sono considerate come luoghi possibili di lesione contusiva. Si discute anche se il danno è primario, neuronale, gliale, reticolare o vascolare. La conclusione è che con ogni probabilità molti tipi di lesioni possono essere responsabili della perdita di coscienza e che vi sono anche molti gradi e tipi di perdita di coscienza.

     

Electroencephalographic indices in concussion of the brain

In 13 patients (7 men and 6 women) aged 19-44 yrs, 28 yrs at average, suffering symptoms of giddiness, nausea, vomiting, unconsciousness, the functional state of brain, using electroencephalography, was investigated. In 62% patients, according to the background electroencephalography data, the total power of low rhythms (teta + delta) had exceeded the total power of rapid rhythms (alfa + beta) in every 11 (68%) investigated brain dots of total 16. Quantitative diagnostic criterion for the brain commotion diagnosis confirmation was created, basing on the investigation results analysis performed: the total power of a slow rhythms exceeding over total power of rapid rhythms in majority (more than 68%) of the brain investigated region dots.     

Immediate neurocognitive effects of concussion

OBJECTIVE: To prospectively measure the immediate neurocognitive effects and early course of recovery from concussion and to examine the effects of loss of consciousness (LOC) and posttraumatic amnesia (PTA) on the severity of neurocognitive impairment immediately after concussion. METHODS: A sports-related concussion research model was used to allow prospective immediate evaluation of concussion. A total of 2385 high school and college football players were studied. Ninety-one players (3.8%) sustained concussions during the study. A brief neurocognitive and neurological screening measure, the Standardized Assessment of Concussion, was used to assess cognitive functioning before the football season, immediately after injury, and 15 minutes, 48 hours, and 90 days after injury. RESULTS: Standardized Assessment of Concussion scores immediately after concussion were significantly lower than the preseason baseline score and the noninjured population baseline mean, even for injured subjects without LOC or PTA. Subjects with LOC were most severely impaired immediately after injury, whereas those without LOC or PTA were least impaired. Significant impairment was also detected 15 minutes after injury, but all three groups returned to baseline levels of cognitive functioning within 48 hours. CONCLUSION: These findings are the first to demonstrate not only that a gradient of increasing concussion severity is represented by PTA and LOC but also that measurable neurocognitive abnormalities are evident immediately after injury without PTA or LOC.     

Attentional deficits in concussion

Primary objective: The purpose of the present study was to examine deficits in the alerting, orienting and executive components of attention in individuals who have recently suffered a concussion.

Research design: A group design was used in which the performance by individuals with concussion was compared to control subjects matched for age, height, weight and activity level.

Methods and procedures: Participants completed the Attentional Network Test (ANT) that breaks down attention into alerting, orienting and executive components. Reaction time and response accuracy were the dependent variables.

Main outcomes and results: It was found that only the orienting and executive components of attention were affected by concussion, whereas the alerting component was normal. Furthermore, participants with concussion required a significantly longer time than controls to initiate correct responses.

Conclusions: These results suggest that the orienting and executive components of attention are most susceptible to the effects of concussion.     

Neuropsychological deficits following concussion

The term 'concussion' has been applied to head injuries of varying severity. Most studies have examined subjects suffering concussion of a severity requiring hospital observation, usually as a consequence of motor vehicle accidents. Milder concussive injuries such as those resulting from contact sport are often not reported in hospital-based studies. In this study, subjects with mild concussive injuries were studied with the aim of determining if neuropsychological sequelae are detectable. The subjects received their injuries while playing Australian Rules Football. Baseline pre-injury measures on the Paced Auditory Serial Addition Test PASAT , Digit Symbol Substitution Test DSST and Four-Choice Reaction time, involving measures of decision time DT and movement time MT , were obtained in a sample of 130 players. Ten players subsequently concussed were re-tested at 5 days post-injury. A control group of age-matched umpires were asssessed on two corresponding occasions. Analyses of covariance showed poorer performances following concussion on the DSST and DT measures. The results suggested that neuropsychological deficits are detectable after resolution of neurological symptoms in the early stages following mild concussive injury.     

Electrophysiological evidence for the cumulative effects of concussion

Purpose: A study was initiated with the intent of demonstrating the cumulative effects of concussion in junior hockey players using visual event-related potentials and post-concussion syndrome (PCS) self-reports. Methods: Players were assessed at the beginning of the season (pre-injury) and at various times post-injury. Results: The results suggest that players with three or more concussions differed significantly on the several cognitive PCS symptoms as well as for the latency of the P3 response compared to those with no concussion history. Discussion: Event-related potentials are useful indices of the cumulative damage that can occur following multiple concussions. These measures correlate significantly with cognitive self-reports of PCS symptoms. Conclusions: This pattern of results is consistent with the position that each concussion potentially causes brain damage. Cumulative damage can be detected using electrophysiological measures of brain function.     

Food cravings during the first week of concussion

The brain utilizes glucose as its main source of energy. Traumatic brain injuries may alter the brain’s ability to shuttle glucose effectively; therefore, the symptoms experienced may be a signal of the dysregulation. The objective of this cross-sectional study was to investigate the presence of any specific food cravings during the first week post-concussion and if the consumption of such a food decreased the symptoms of concussion. The link to the survey was posted on 4 Canadian organization websites from November 2020 to February 2021. Any individual over 18 years old who had suffered one of more concussions in the past 12 months was included. 73 females and 24 males, the majority aged 18–40 years, completed the survey. Participants with combined carbohydrate and sweet cravings reported significantly more symptoms of increased emotions (p=0.04), irritability (p=0.03), sadness (p=0.04), nervousness (p=0.03), and sleep disturbances (p=0.05) than those without these cravings. Consumption of the craved food did not change the concussion symptoms.