What is the pathophysiology of postconcussion syndrome (PCS)?

Updated: Sep 24, 2018
  • Author: Eric L Legome, MD; Chief Editor: Trevor John Mills, MD, MPH  more...
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Answer

Debate in the literature exists over which symptoms of postconcussion syndrome are due to organic causes and which have a psychological basis. Researchers have hypothesized that early postconcussion syndrome symptoms are more likely to be organic, whereas PCS symptoms that persist beyond 3 months have a nonorganic, psychological basis. While recent research has shown that psychological factors may be present early, other studies using imaging techniques such as magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and magnetoencephalography (MEG) have demonstrated the presence of organic brain injury in patients with persistent PCS at greater than 1 year after injury.

Neuropsychological assessments have pointed toward an organic basis for some of the symptoms of postconcussion syndrome. Patients with PCS have been found to have cognitive deficits in memory, attention, and learning when compared with controls. A prospective study found impaired eye movements in patients with PCS, as compared to controls, that were both persistent and independent of factors such as depression or intellectual ability. [7] Findings from neuropsychological evaluations demonstrate that symptom severity is not necessarily dependent on neurologic status immediately following injury. However, in other series, the length of LOC or posttraumatic amnesia may be correlated with the probability of developing PCS.

Some studies have found certain characteristics such as female sex, noise sensitivity, and anxiety predict development of symptoms. [8] Another study found a simple test in the ED of immediate and delayed memory for 5 words and a VAS for acute headache provided an 80% sensitivity and 76% specificity for the development of PCS. [9] In addition, another study found that higher educational levels, along with mild symptoms and no extracranial symptoms predicted a low likelihood of significant dysfunction from PCS.


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