Mild traumatic brain injury (mTBI) is characterized by a period of unconsciousness for less than 20 minutes, or a score of 13 or above on the Glasgow Coma Scale without unconsciousness. The injury should also show no evidence of deterioration or post traumatic amnesia within 48 hours after the occurrence.
Symptoms and Causes
The symptoms of mTBI are generally categorized into three groups; physical/somatic problems, cognitive dysfunctions, and emotional/personality symptoms.
The physical/somatic problems may include seizures, headaches, fatigue, sleep disturbance, dizziness, light/noise sensitivity, nausea, blurred vision, vomiting, loss of sexual drive and tinnitus.
The cognitive dysfunctions may involve impaired short-term memory, impaired concentration and attention, slower information processing, disorganization, lexical deficits, forgetfulness and distractibility.
The emotional/personality symptoms may include irritability, anxiety, mood swings, depression, impatience, lower frustration tolerance, and explosive temper.
The mTBI symptoms, listed above, are primarily caused by mechanical forces and the effects they produce. Mechanical forces typically include rapid acceleration/ deceleration forces that can affect cortical regions and rotational forces that can twist the brainstem. In addition to damaging the area directly involved in the impact, mTBI may also produce a coup-contra-coup effect or a shearing effect. The coup-contra-coup effect involves brain injury at the site of impact, as well as the site 180º opposite this site. The shearing effect, also known as diffuse axonal injury, involves the unraveling of myelin in the brain. By unraveling the myelin sheaths around the axons, mTBI slows down the speed of electrical communication between cortical regions.
Brain injury may cause generalized attenuated cerebral activity, specific areas of slow-wave activity, or disconnection syndromes. Usually, with closed head injury, contusion (bruising) occurs in the absence of skull penetration. The brain bruises as it strikes against the skull in rapid acceleration-acceleration or coup-counter-coup injuries. These result in laceration, intracranial injury to the brain, hemorrhage, and/or axonal injury. Individuals with mTBI often show various deficits known as post concussive symptoms, consisting of slowed information processing, memory deficits, and/or some degree of language impairment as well as executive and frontal lobe dysfunction.
The most common tools used to diagnose mTBI include past medical history, CAT scan, MRI, standard EEG and neurological exams. The main problem with these tools is their ineffectiveness when it comes to detecting subtle impairments. This diagnostic battery has been known to produce normal test results, despite patient complaints of significant neurocognitive dysfunctions.
Another type of imaging that has become popular in the diagnosis of mTBI is the Quantitative Electroencephalograph (QEEG). The QEEG reads a patient's real-time electro-cortical activity and compares it to a normative database to detect any dysfunctions. By comparing the acquired data to a normative database, the QEEG is able to detect minute changes in brain activity that other methods might not be able to detect. The QEEG also enables the discrimination between mechanical injury and diffuse axonal injury.
The traditional treatment regimen for mTBI focuses on medical management, psychotherapy, coping skills, vocational rehabilitation, counseling and cognitive rehabilitation. This combination of treatments usually involves a wide array of specialists; ranging from physicians and physical therapists to psychologists and social workers. Despite the fact that these interventions are clearly beneficial to severely injured individuals, the research has shown mixed results for the mildly injured population. This treatment strategy may also be very expensive, since brain injured patients receive an average of 250 hours of treatment.
A relatively new and promising treatment for mTBI is EEG neurofeedback training. Guided by QEEG testing, neurofeedback trains an individual to normalize and stabilize brain function. By providing the client with real time EEG feedback, the clinician trains the client to increase the production of desired brainwaves in specific cortical regions (regions that might be injured by brain trauma). In addition to helping mTBI patients' regain their cognitive abilities, neurofeedback also dramatically cuts the costs of the traditional treatment procedures by successfully treating patients in an average of 40 sessions.
EEG neurofeedback treatment stems from the revolutionary biofeedback work of Dr. Barry Sterman. Sterman found that by training epileptics to increase SMR (12-15 Hz) brainwaves, he could significantly reduce the amount of their seizures. Subsequent biofeedback experimentation by Sterman and Lubar revealed increased attentiveness and concentration among their test subjects. From its meager beginnings, neurofeedback has grown into a treatment option that continues to broaden its range of applications.
In 1941, Williams and Denny-Brown documented abnormal EEG activity subsequent to penetrating traumatic brain injury, mild traumatic brain injury (mTBI), or closed head injury. In the 1980's, clinicians began applying neurofeedback training to the treatment of mTBI. Bruner (1989) reported that his subjects regained their cognitive functioning after training high alpha and SMR (10-14 Hz). Some researchers, such as Tansey, have successfully trained mTBI patients with SMR (12-15 Hz). Ayers has reported significant results by inhibiting theta (4-7 Hz) and rewarding Beta (15-18 Hz). Regardless of the differences in protocol, these researchers have reported significant returns to pre-morbid functioning as a result of neurofeedback training.
In order to obtain the best results from neurofeedback, clinicians must perform a comprehensive evaluation. This evaluation should examine medical history, mental status, neurophysiological screening, information from related professionals (i.e. physicians, neurologists, teachers, etc.), and Quantitative Electroencephalographic data (QEEG). Together, this information will provide the clinician with a road map for developing the best possible treatment.
1. Hoffman, D. A., Stockdale, S., Hicks, L., Schwaninger, J. (1995). Diagnosis and Treatment of Head Injury. Journal of Neurotherapy, Vol. 1 (#1), pp. 14-21.
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