After a concussion, symptoms tend to develop quickly and usually resolve within a few weeks. However, sometimes they may come on late or persist for months following the incident. These are post-concussive symptoms, and they vary from subtle to severe. Many of the symptoms are treatable through various methods.
Headaches that last longer than is typical or occur more frequently are the most common post-concussive symptom. Most people describe them as tension-type headaches, though some experience migraines. Up to 32% of post-concussive patients report that the headaches continue for up to a year after the concussion.
As many as 80% of people with post-concussive symptoms experience extreme dizziness. For around a quarter of individuals, this symptom continues for a year after the concussion. Studies show that older adults have a higher risk for dizziness, which also increases their risk of injury, or worse, from traumatic falls. Research has yet to find a definitive cause for post-concussive dizziness.
Vision and Other Sensory Issues
Several vision issues can also persist after a concussion. Around 14% of people with post-concussive symptoms develop a blurry vision. Some experience more specific double vision or diplopia. In many cases, other sensory issues accompany the vision changes, such as tinnitus or sensitivity to light and noise.
Coordination and Balance
Medical experts have identified a range of posture, coordination, and balance issues that may follow a concussion. Other symptoms, primarily dizziness and problems with vision, are often partially responsible for post-concussive balance changes. However, some studies indicate that damage to certain parts of the brain directly inhibits proper balance and posture.
Higher mental function changes are also potential post-concussive symptoms. Among these, the most prevalent affect attention and cognition. These symptoms can be subtle or more pronounced. Projects and tasks that would previously have been simple to complete may feel more difficult, seemingly without cause. While cognitive symptoms tend to improve within six months to a year after the concussion, they can also persist, in some cases.
Many people have issues with memory, especially short-term memory, after a concussion. These problems are often less noticeable than other symptoms. Typical or everyday situations like forgetting an appointment often become more frequent. Some studies indicate that memory changes are only statistically prominent in cases of repeated concussive impacts, as can affect certain types of athletes.
After a concussion, various issues can affect sleep patterns. Extreme fatigue leading to long periods of sleep is common. Alternatively, some people deal with insomnia that prevents or limits sleep. Many people find themselves having fewer or less vivid dreams. Other post-concussive symptoms may trigger sleep disturbances that a person mistakenly attributes to insomnia.
Head injuries that cause a concussion may also damage areas of the head or brain responsible for hearing, including the tympanic membrane, ossicles, or areas of the middle ear. Hearing loss may occur in up to 20% of people after concussive trauma. Most of the hearing loss affects high-frequency hearing, though the low-frequency loss is possible. Some may experience ringing in the ears.
Some people experience psychological and behavioral changes after a concussion. While the individual may not notice these shifts, they are clear to others who are familiar with the person’s original personality. Mood swings are typical in post-concussive situations. Some people become more apathetic while others act more aggressively. The most common change in personality is an increase in irritability.
Depression and Anxiety
Concussions can also lead to anxiety disorders, which may explain some of the post-concussive personality changes. Recently, experts have recognized that many post-concussive symptoms are similar to those of depression disorders. This has led to research focusing on depression and anxiety as potential triggers for the other symptoms. Some researchers have also made links to post-traumatic stress disorder.