Potential Effects

What are the Potential Effects of TBI?

Chronic Traumatic Encephalopathy (CTE)

CTE is a brain disease that can only be diagnosed after death. It has been linked to specific changes in the brain that affect how the brain works. The research to-date suggests that CTE is caused in part by repeated traumatic brain injuries, including concussions, and repeated hits to the head, called subconcussive head impacts.


The National Institutes of Health (NIH) launched a major program to better understand CTE, its causes, and how to diagnose it among living persons. Learn more about NIH research efforts by visiting the NINDS Traumatic Brain Injury Information PageExternal. The Report from the First NIH Consensus Conference to Define the Neuropathological Criteria for the Diagnosis of Chronic Traumatic EncephalopathyExternal has additional information.

The severity of a traumatic brain injury (TBI) may range from “mild” (i.e., a brief change in mental status or consciousness) to “severe” (i.e., an extended period of unconsciousness or amnesia after the injury).

A TBI can cause a wide range of functional short- or long-term changes affecting:

  • Thinking  (i.e., memory and reasoning);
  • Sensation (i.e., sight and balance);
  • Language  (i.e., communication, expression, and understanding); and
  • Emotion  (i.e., depression, anxiety, personality changes, aggression, acting out, and social inappropriateness).1

A TBI can also cause epilepsy and increase the risk for conditions such as Alzheimer’s disease, Parkinson’s disease, and other brain disorders.

About 75% of TBIs that occur each year are concussions or other forms of mild TBI.2

Repeated mild TBIs occurring over an extended period of time can result in cumulative neurological and cognitive deficits. Repeated mild TBIs occurring within a short period of time (i.e., hours, days, or weeks) can be catastrophic or fatal.3

For information on how to prevent TBI and the potentially serious effects from this injury, please visit our TBI Prevention page.

CDC’s HEADS UP campaign also includes steps to help protect children and teens from concussion and other serious head and brain injuries—both on and off the sports field. Learn more at HEADS UP’s Brain Injury Safety Tips and Prevention page.

General Tips to Help Aid in Recovery:
  • Get lots of rest. Don’t rush back to daily activities such as work or school.
  • Avoid doing anything that could cause another blow or jolt to the head.
  • Ask your health care professional when it’s safe to drive a car, ride a bike, or use heavy equipment. Your ability to react may be slower after a brain injury.
  • Only take medications your health care provider has approved. Don’t drink alcohol until your health care provider says it’s OK.
  • Write things down if you have a hard time remembering.
  • You may need help to re-learn skills you lost. Your health care professional can help arrange for these services.4


  1. National Institute of Neurological Disorders and Stroke. Traumatic brain injury: hope through research. Bethesda (MD): National Institutes of Health; 2002 Feb. NIH Publication No.: 02-158.
  2. Centers for Disease Control and Prevention (CDC), National Center for Injury Prevention and Control. Report to Congress on mild traumatic brain injury in the United States: steps to prevent a serious public health problem. Atlanta (GA): Centers for Disease Control and Prevention; 2003.
  3. Centers for Disease Control and Prevention (CDC). Sports-related recurrent brain injuries—United States. MMWR 1997;46(10):224–227.
  4. Centers for Disease Control and Prevention (CDC). Facts about concussion and brain injury: Where to Get Help. 2010.