Post-concussion syndrome (PCS) occurs in some people who have had a concussion and who develop symptoms like headache, stimuli sensitivity, poor memory and concentration, and sleep problems several weeks after the concussion occurred. These symptoms can persist for weeks or years after the initial brain injury.
It’s the topic of my interview this month with Dr. Mel Glenn, a physical medicine and rehabilitation (PM&R) physician who specializes in brain injury medicine. He is the Director of Outpatient and Community Brain Injury Rehabilitation at Spaulding Rehabilitation Hospital, the Medical Director at NeuroRestorative and at Community Rehab Care, a faculty member at Harvard, and a physician at Massachusetts General Hospital.
In the interview, Dr. Glenn and I discuss how PCS is diagnosed and why diagnosis can be tricky. The difficulty in diagnosis is part of the reason PCS is controversial in the medical community. Let’s look at how it’s done.
Checklists and Self-Reported Symptoms in Diagnosing PCS
Checklists and questionnaires help screen for symptoms initially when a patient reports the symptoms they’re experiencing. Well-known checklists include the Post- Concussion Syndrome Checklist, the Post-Concussion Syndrome Symptoms Scale, the British Columbia Post Concussion Symptoms Inventory, and the Rivermead Post Concussion Symptoms Questionnaire. Some physicians use a narrative history-taking approach rather than a checklist or they use both approaches to gather information from the patient.
Doctors also commonly use a variety of tests to look for objective evidence of cognitive impairments, memory problems, and verbal ability.
Criteria for PCS Diagnosis in the ICD-10 and DSM-IV
For many years, physicians relied on two widely used reference works when diagnosing PCS.
One is the WHO’s International Classification of Diseases manual. The latest edition is the ICD-10 (The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision), which lists the following six symptom categories for post-concussion syndrome:
- headache, dizziness, malaise, fatigue, noise tolerance
- irritability, depression, anxiety, emotional liability
- subjective concentration, memory, or intellectual difficulties without neuropsychological evidence of marked impairment
- reduced alcohol tolerance
- preoccupation with above symptoms and fear of brain damage with hypochondriacal concern and adoption of sick role
To meet the ICD-10 criteria, a patient must have symptoms in at least three of the six categories. They must also have experienced a brain injury severe enough to result in loss of consciousness within the preceding four weeks. (This is interesting because loss of consciousness is not required for a diagnosis of concussion or mild brain injury.)
The other resource has been the American Psychiatric Association’s DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition), which lists the following symptoms for postconcussional disorder:
- becoming fatigued easily
- disordered sleep
- vertigo or dizziness
- irritability or aggression on little or no provocation
- anxiety, depression, or affective instability
- changes in personality (e.g., social or sexual inappropriateness)
- apathy or lack of spontaneity
To meet the DSM-IV criteria, a patient must be experiencing three or more of the symptoms, which cause “significant” impairment. The symptoms must have lasted at least three months, and the onset must have occurred shortly after a “significant” concussion.
However, the DSM-IV is the previous version of the manual, and it was replaced in 2013 with the DSM-V, which omits the syndrome completely. This has added to the controversy around PCS.
Are Brain Scans Used to Diagnose PCS?
As of right now, brain scans like CTs and MRIs can’t be relied on to diagnose PCS. Conventional imaging techniques are best at showing internal bleeding and physical damage to the skull and brain after more severe injuries, and in the hours and days after the injury, but they aren’t reliable in showing evidence of other kinds of “invisible” or microscopic damage to the brain, especially weeks and months after the injury.
Still, some progress is being made in this area. Over the last few decades, researchers have been developing techniques to show changes in the brain after mTBI using both older imaging techniques like MR Spectroscopy MRS) and PET scans in a new way, and new imaging techniques like diffusion tensor imaging and functional MRI. (You can read the literature on these developments here, here and here.)
What Happens After PCS is Diagnosed?
After diagnosis comes treatment, which is the subject of the next blog.
Remember to watch my interview with Dr. Mel Glenn in its entirety if you want to learn more about post-concussion syndrome. You’ll find it right here.