Five different types of mild traumatic brain injury (mTBI) have been listed by an international working group on concussion, to better define diagnosis, treatment and prognosis.
Led by Stanford University researchers, the multidisciplinary expert workgroup used a literature search and meta-analysis to define the five most common acute concussion subtypes and two associated conditions seen within three days of injury.
The five subtypes are:
- Headache — Symptoms include different types of headaches, including migraines. Initially treated with headache management.
- Cognitive — Symptoms include problems with attention, reaction time, working memory, new learning, memory retrieval, organization of thoughts and behavior. Initially treated with neuropsychological assessment and treatments.
- Vestibular — Symptoms include dizziness, fogginess, lightheadedness, nausea, vertigo and disequilibrium. Initially treated with balance and vestibular-ocular training with a physical therapist.
- Ocular-motor — Symptoms include difficulties with reading and driving, eye strain, problems changing focus between near and far, blurred or double vision, eye pain, vision-derived nausea and photophobia. Initially treated with dynamic vision training with an optometrist.
- Anxiety-Mood — Symptoms include nervousness, hypervigilance, ruminative thoughts, depressed mood, anger, irritability, loss of energy, fatigue and feeling more emotional, overwhelmed or hopeless. Initially treated with counseling, including cognitive-behavioral therapies.
However the researchers, writing in Neurosurgery, warned that the subtypes are not mutually exclusive and often cluster together.
“Early on, the headache subtype is the most prevalent for both adult and pediatric populations, and it usually co-exists with the vestibular and ocular-motor subtypes,” said co-author Professor Jamshid Ghajar, a neurosurgeon at the Stanford Concussion and Brain Performance Center and President of the Brain Trauma Foundation.
“Weeks to months after injury, the mood subtype with symptoms of anxiety and depression predominates, usually because of inadequate interventions. The prevalence of the vestibular subtype was also very high for paediatric patients,” he added.
The working group found that headache/migraine and cognitive were the most common concussion subtypes for paediatric and adult populations, while the vestibular subtype was also common in children.
Sleep disturbance and cervical strain were commonly associated with all five concussion categories. Symptoms included difficulty falling asleep, frequent awakenings and fatigue, while cervical strain symptoms included neck pain, neck stiffness and upper extremity weakness.
The authors said they hoped the classifications would help guide diagnosis and management of concussion, particularly for children who may not be able to express their symptoms very well.
“Clinicians should assess each subtype of impairment in the acute setting following injury, encourage early cardio exercise and provide prognostic counseling for mood and sleep disturbances.”