Post-concussion syndrome
About 10% of people with PCS develop sensitivity to light or noise, about 5% experience a decreased sense of taste or smell, and about 14% report blurred vision. People may also have double vision or ringing in the ears, also called tinnitus. PCS may cause insomnia, fatigue, or other problems with sleep.
Post-traumatic seizure
The most important factor in whether a person will develop early and late seizures is the extent of the damage to the brain. More severe brain injury also confers a risk for developing PTS for a longer time after the event. One study found that the probability that seizures will occur within 5 years of injury is in 0.5% of mild traumatic brain injuries (defined as no skull fracture and less than 30 minutes of post-traumatic amnesia, abbreviated PTA, or loss of consciousness, abbreviated LOC); 1.2% of moderate injuries (skull fracture or PTA or LOC lasting between 30 minutes and 24 hours); and 10.0% of severe injuries (cerebral contusion, intracranial hematoma, or LOC or PTA for over 24 hours). Another study found that the risk of seizures 5 years after TBI is 1.5% in mild (defined as PTA or LOC for less than 30 minutes), 2.9% in moderate (LOC lasting between 30 minutes and 1 day), and 17.2% in severe TBI (cerebral contusion, subdural hematoma, or LOC for over a day; image at right).