THE POST-CONCUSSION SYNDROME

Mild head injuries frequently result in the post-concussion syndrome (PCS), a constellation of symptoms that can include headaches, dizziness, nausea, irritability, imbalance and problems with concentration and memory. The specific etiology of these symptoms is seldom investigated since they are assumed to be secondary to brain concussion and are accepted as part of a syndrome diagnosis. Symptoms of vestibular system trauma, however, estimated to occur in up to 65% of head injuries (Griffiths, 1979), are virtually identical to those of the post-concussion syndrome. Three of the above PCS symptoms, dizziness, imbalance and nausea, are the direct result of vestibular system dysfunction, and the remaining symptoms are common secondary effects.

While the majority of mild head injury patients recover quickly, returning to baseline functioning within 3-6 months, up to 15% of these patients have prolonged recoveries or never recover completely (Levin et.al., 1987). Existing treatment paradigms have largely failed this population of patients (Ruff et.al. 1994). Incomplete recovery in this group has been attributed to a variety of factors, including the residual effects of brain injury (Barth et. al., 1983), chronic pain (Smith-Seemiller et. al., 2003), emotionally-based symptoms (Eysenick, 1991), and outright malingering (Jacobson, 1995). Seldom has vestibular system pathology been considered as a possible explanation for why these patients remain “miserable” and unable to recover.