Head Injury and Mild Brain Concussion

Y. yanagida, H, Ando, K, Seki, M, Yamaguchi

Transient Elongation of P300-Latency by American Football Training

INTERNATIONAL NEUROTRAUMA SYMPOSIUM (INTS)

Garmisch-Partenkirchen, Germany, October 2-6, 2000

Abstruct; American football players sometimes feel slight fainting-like sensation or dizziness during training. This condition was compared with mild concussion caued by a motorcycle accident. Latency of the event related potential (P300) was prolonged for many hours after the accident, but that of the football players recovered within a few minutes.

Introduction; During routine traning of American football, players sometimes feel slight faintinglike sensation or dizziness just after the attacking contact to their heads. This condition may be called as a mild concussion defined by Gennarelli (1984). A typical mild concussion case caused by a motorcycle accident shoowed no abnormal findings in her CT scan, but latency of P300, one of an vent related potential (ERP), was significantly prolonged for many hours. We studied whether the attacking contact to the heads of American football players caused the similar changes to the ERP. P300 response recorded about 5 hours after the accident. Note the peak latency of the P300 i almost 400 msec and amplitude is low. P300 response recorded about 50 days after the accident. Note the peak latency of the P300 have shortened to the normal range.

Methods; The event related potentials (P300) were recorded by using auditory odd ball paradigm. Ten healthy players of college American football team (mean age:20) were consented. The control P300 response was recorded at first. Then, the player in helmet and shoulder protectors hit his head several times to other object person as an attacking style of usual training manner. When he felt slight fainting-like sensation or dizziness, he stopped hitting and P300-recordings were started within 2min. The first and second 100 responses were collected (took 150 sec. each) and averaged separately.

Results; Mean latency of the control recordings was 319.2 msec (S.D.=16). After the impact, mean latency was increased to 345.6 msec (S.D.=45). The difference was significant (P=0.038), when compared with the control by paired t-test. However, the latency recovered very rapidly. The mean latency of the second 100 responses was 330.8 msec (S.D.=29, difference: non-significant P=0.13).

Discussion; When football players feel fainting-like sensation or dizziness after head hitting in the training, latency of the P300 elongated significantly. This condition may be called as mild concussion, but the changes in the latency were small and recovered very soon. Even prolongation of the latency of P300 had lasted for several hours, the case shown in Figure--- have recovered completely.

Conclusion; Judging from the present study, the impact to the American football player's head in the helmet is mild and harmless.

Y.Yanagida,K.Hirakawa, H.Ando, K.Seki, T.Yamada, M.Yamaguchi

AN EXPERIMENTAL STUDY OF MILD CONCUSSION DURING A ROUTINE TRAINING OF AMERICAN FOOTBALL PLAYERS USING ELECTROPHYSIOLOGICAL AND NEUROPSYCHOLOGICAL TECHNIQUES

INTERNATIONAL CONFERENCE ON RECENT ADVANCES IN NEUROTRAUMATOLOGY
Taipei, Taiwan, ROC.　　 November 20-23,1999

Objectives: Fainting-like sensation or light headedness just after a strong impact to the head is experienced not infrequently even in the civilized modern life. After mild head injury, rather long- lasting and intractable complaints are often manifested as the so-called postconcussion syndorome. The mild impairment of mental function by injury, therefore, must be investigated to obtain much more detailed information using physiological and psychological techniques. As student players of American foot ball game have experienced this mild concussion during their daily routine training, we studied this condition by estimating P300 as an event-related poten- tials and some neuropsychological tests at the pre- and posttraumatic instances.

Methods: Ten, healthy, well-trained college players of American football game of 18 to 21 years old were consented and participated this project voluntarily. Mean duration of those experience of foot ball is approximately 2 years. The students were examined by Neuropsychological test battery about 1 week prior to the concussion. The whole experiment of the mild concussion was planned as follows: Each player in the helmet and shoulder protectors hit his head as the attacking style to other object person with routine training manner. Immediately after the impact, the estimation of the event- related potentials was performed using auditory stimuli of odd ball paradigm. All player was expected to push switch button when the higher tone sound (event) was given instead of low tone sound. At the same time, reaction time from the onset of stimulus to the time of pushing button was also measured. The latency of P300 was measured from a composed figure which was produced within about 2 min duration (20 oddball stimuli). The student, then, examined by psychological test battery for recent and immediate memory and for attention (Rey's complex figure test, verbal paired associates (easy and hard pairs), and letter cancellation test).
Results: Eight men out of 10 represented significantly elongated latency of P300. Mean difference was 30.4 msec, and the difference was significant (P<0.01by paired t-test). Longer reaction time was also found in 7 players (P<0.05). By verbal paired associates (easy pairs), a significant deterioration (P<0.05) was shown by Wilcoxon's signed rank test.
Conclusion: Latency of P300 and reaction time elongated after mild concussion. Immediate memory may be also disturbed. Further investigation of mild concussion without apparent unconsciousness is of importance in the neurotraumatology.

Yanagida Y, Yamada T, Yamaguchi M, and Hirakawa K
Traumatic Headache in American Football Players.
The 1997 Nagano Symposium on Sports Sciences, edited by H Nose, ER Nadel, and T Morimoto, Cooper Publishing Group, Carmel, IN, pp581-584,1998.
 

Abstract
It is well known that almost any sport can cause neurologic injuries involving any levels of the nervous system. However, it should be emphasized that sport and exercise also induce a wide variety of non - traumatic neurologic problems including headache. Sport - and exercise - related headache is important aspects of sport neurology and sport medicine in general, although little attention has been paid to this headache. Also it has been often misdiagnosed or underreported. The substance of sport and exercise headache among Americal football players in Japanese university (106 male students: 20.7&plusmn;1.4 years of age) was assessed using questionnaire. Of the 106 players, 69 players (65%) had experienced head injuries, resulting from blows to the head. Traumatic headache was noted after following a blow to the head in a football field. Incidence of post- traumatic headache was 12/19 (63%) and 27/45 (60%) in the concussion group and in the alert group at blow, respectively. On 22 cases out of 39 (56.4%), headache disappeared within 1 day and all player became headache free within 3 weeks after the injury.
Key words: headache, american football player, questionnaire, loss of consciousness, head injury,

Yanagida Yasuyoshi, Fujiwara Satoshi, Mizoi Yasuhiko, Yamaguchi Michio and Moriwaki Toshimichi
Deformation of Human Dry Skull Caused by Impact--- An Experimental Study Using Modal Analysis ---
Bulletin of Allied Medical Sciences Kobe (japanese) 1992; 8: 45-54.
 

Abstract
It is generally expected that cerebral contusion occurs due to intracranial pressure changes, while the intracranial pressure change is thought to be caused by the skull deformation and/or acceleration by an impact. However, these mechanism are not yet clarified sufficiently. The purpose of this study is to analyze the deformation of the human skull by using the modal analysis technique so as to analyze the dynamic charecteristics of the skull. The modal analysis of the skull deformation proved the inbending in both frontal and occipital regions of the skull and the outbending in both parietal and temporal regions immediately after the impact. They are followed by the reverse deformation in each region. Such vibrating motion of the skull was repeated and damped (resonance frequency = about 587.5 Hz) by the impact. The parietal and temporal regions were 5.5 times as large as the frontal and occipital regions, although the dimension of skull deformation is quite different in both sides. The deformation of the skull dose not take place simultaneously at the impact side and the opposite side, but the deformation at the opposite side delays by 0.2ms compared with that of the impact side, In other words, the deformation is trans- mitted from the impact side to the opposite side. It is conceived from the results of experiments that the deformation of the human skull is similar to that of a ball, and it is expected that the deformation influences intracranial pressure.
Key words: Deformation, Intracranial pressure, Cerebral contusion, Modal analysis, Impact.

Fujiwara Satoshi, Yanagida Yasuyoshi, Nishimura Akiyoshi, Ueno Yasuhiro, Adachi Junko, Tatsuno Yoshitsugu and Mizoi Yasuhiko
Recent Advances in the Study on the Mechanism of Brain Injury.
THE JAPANESE JOURNAL OF LEGAL MEDICINE 1993;47,387-397.

Abstract
A cerebral contusion and DAI (diffuse axonal injury) are practically very important in a medico- legal case of the closed head injury. In this paper, we will report the epitome of the recent advances in the study on the mechanism of them. Coup contusion can be mainly attributed to the skull inbending and/or the skull fracture which develop in the impact region. As to the mechanism of the contrecoup contusion, several theories are reported. During rotational movement of the head, intracerebral shear strains would be produced because of brain lag (Holbourn's rotation theory). Anatomical features of the skull plays an important role (Gurdjian). Relative movement between a brain and a skull induces intracranial cavitation due to pressure gradient (Gross's cavitation theory). Brain is injured by deformation pressure induced by skull deformation and acceleration one done by a movement of the head (Lindenberg). The last one is Courville's trans- mitted waves of force theory. As to DAI, there is Gennarelli's theory. During a rotational movement of a brain caused by high rate of angular acceleration operating for a long period, intracerebral shear strains occur and injure a brain. As to the brain injuries which include a cerebral contusion and DAI, two theories are reported. Centripetal progression of strains to the core of a brain injures the brain (Ommaya). Natural frequency of impact determines the nature of resulting injury to the brain (Willinger).
Key words: Wounds and injuries, Brain injuries, Cerebral contusion, Diffuse axonal injury, Mechanism

Yanagida Y, Fujiwara S, and Mizoi Y
Differences in Intracranial Pressure Caused by a Blow or a Fall--- An Experimental Study Using Physical Models of the Head and Neck.
Forensic Sci Int 1989;41:135-145.
 

Summary
In case of a severe head injury caused by a fall, coup contusions are either absent or very minor, in contrast to presence of extensive contrecoup damage. In cases of a severe blow to a head, however, the reverse occurs, with contrecoup lesions a rarity and coup damage extensive. To investigate this further, head injuries caused by a 'blow' or a 'fall' have been studied, using physical human models of the head and neck, both filled with distilled, degassed water and fixed onto a dummy torso. An impact of a constant magnitude was applied to the midoccipital region in 'blow' and 'fall' experiments, and the acceleration of the head and changes in the intracranial pressure were measured, with the resulting data analyzed by a computer. In both experiments, the peak amplitude of the acceleration pulse were almost the same. Similarly, the intracranial pressure curve at the impact site consisted of a positive pulse that hardly differed, nor did the peak amplitude of that pulse vary significantly. In the 'blow' experiment, however, the intracranial pressure curve at the site opposite the impact consisted of a negative pulse, whereas in the 'fall' experiment, the intracranial pressure recorded at the same area was negative but of a longer duration, with an absolute value that was slightly greater. Our results indicate that an impact to the head triggers a different rsponse in the intracranial space, dependent on whether that impact force was caused by a 'blow' or a 'fall'.
Key words: Head injury; Cerebral contusion; blow injury; Fall; Physical model; Intracranial pressure

Fujiwara S, Yanagida Y, and Mizoi Y
Impact-Induced Intracranial Pressure Caused by an Accelerated Motion of the Head or by Skull Deformation; An Experimental Study Using Physical Models of the Head and Neck, and Ones of the Skull.
Forensic Sci Int 1989;43:159-169.
 

Summary
An impact incurred by the movable head may bring about a change in intracranial pressure and this change may play an important part in the occurrence of the cerebral contusion. We have carried out the following experiments to determine whether the intracranial pressure change was attributed to an accelerated motion of the head or to a skill deformation. In the blow experiment in which the head was accelerated, a positive peak in the intracranial pressure was recorded immediately after impact at the impact site and a negative one at a site opposite the impact. In the one in which the skull could be deformed, the intracranial pressure curves at both sites contained harmonics. The model analysis revealed an inbending in the frontal and occipital regions of the skull and an outbebding in the parietal and temporal regions immediately after impact, followed by a reverse deformation. Regarding the intracranial pressure change, positive pressures ware recorded in the frontal and occipital regions immediately after impact, followed by a negative one. This study demonstrated that the positive and negative peaks were caused by the accelerated motion of the head, and that the curve of the intracranial pressure changes contained harmonics which were caused by the deformation of the skull.
Key words: Wounds and injuries; Cerebral contusion; Intracranial pressure change; Acceleration and deformation; Modal analysis; Physical model

Fujiwara Satoshi, Yanagida Yasuyoshi, Fukunaga Tatsushige,
Mizoi Yasuhiko and Tatsuno Yoshitsugu
Studies on Cerebral Contusion in the Fatal Cases by Blow, Fall and Fall Down.
THE JAPANESE JOURNAL OF LEGAL MEDICINE (Japanese)
1986;40,377-383.
 

Abstract
For the purpose of studing on the pathogenesis of cerebral contusion, we investigated 105 autopsied cases which died from head injuries. In these cases, the site of impact of the head was classified into a frontal or a posterior region and moreover the type of impact was done into a blow, a fall or a fall down. In each site and type of impact, the contusion was classified into a coup lesion and a contrecoup lesion. With the impact to the lateral region of the head, the coup lesions were more frequent and more severe than the contrecoup lesions in 88.9% of all cases in blows, the contrecoup lesions were in 80.0% in falls and there were merely the contrecoup lesions in almost all cases of the fall down. With frontal impacts, there were merely the coup lesions in all cases of the blow and there were merely the coup lesions in 8 cases out of 11 in falls, especially in 3 cases out of them the contrecoup lesions were found in the occipital lobes where the contu- sions were rarely seen in general. With posterior impacts, the coup lesions were more frequent and more severe in all cases of the blow, the contrecoup lesions were in 93.3% of all cases in falls and there were merely the contrecoup lesions in almost all cases of the fall down. Regarding the relationship between the contusions and the skull fractures, the coup lesions invariably underlay the skull fractures and the skull fractures were also severe in the cases in which the coup lesions were severe. The present study demonstrated that the coup contusions were more easily 'caused than the contrecoup contusions in blows and the contrecoup contusions were more easily caused than the coup contusions in falls and falls down, especially falls down.
Key words: Wounds and injuries, Head injuries, Coup and contrecoup contusion, Blow and fall, Imapact site of head.

Mizoi Yasuhiko, Tatsuno Yoshitsugu, Nakanishi Kouichi, Satoshi Fujiwara , and Yanagida Yasuyoshi
The Mechanism of Occurrence of Ring Fracture at the Base of the Skull
Jpn J Legal Med 36,562-568,1982.
 

Abstract
Seven autopsy cases which had completely or nearly typical ring fracture around the foramen magnum at the base of the skull were reported. One of them was a case who fell from the deck of a cargo boat into the hold and bumped his parietooccipital region against the floor, and six were fatal cases resulting from car accident. In three cases of the latters, when one had been walking and two riding bicycle, the victims were collided from behind by family car with high speed, res- pectively. Of the remaining three cases, one was a pedestrian whose forehead was struck by the front of a cab-typed truck, another was run over the back of the neck and shoulder by a truck, and the third had been a fellow passenger in a family car which collided against another car and the victim had the ring fracture which was made due to a pushing-up action of the spine against the base of the skull. The ring fracture found in six cases except the last one was estimated to be produced according to the mechanism of an extraction of the base with the spine from the skull and/or a levering or shearing effect at the base, and it was also presumed that the mechanism was intensified due to an overextension of the neck at the time of the car-human collision.
Key words: Wounds and injuries, Skull fractures, Traffic accidents.