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.
Concussions in sport
Repeated concussions have been linked to a variety of neurological disorders among athletes, including CTE, Alzheimer's Disease, Parkinsonism and Amyotrophic lateral sclerosis (ALS).