Traumatic Brain Injury: Signs and Symptoms

Mild TBI Symptoms

A traumatic brain injury (TBI) can be classified as mild in loss of consciousness and/or confusion and disorientation is shorter than 30 minutes.  While MRI and CT scans are often normal, the individual has cognitive problems, such as headache, difficulty thinking, memory problems, attention deficits and/or mood swings. These injuries are commonly overlooked.  Even though this type of TBI is called “mild”, the effect on the family and the injured person can be significant.

These symptoms may not be present or noticed at the time of injury. They may be delayed days or weeks before they appear.  The person often looks normal in spite of not feeling well or thinking normally.  This makes the diagnosis easy to miss.  Frustration at work or when doing everyday activities may bring the person to seek medical care.

Mild TBI is:

  • Most prevalent TBI
  • Often missed at time of initial injury
  • 15% of people with mild TBI have symptoms that last one year or more
  • Post injury symptoms are often referred to as post concussive syndrome

Common Symptoms of Mild TBI

  • Fatigue
  • Headaches
  • Visual disturbances
  • Memory loss
  • Poor attention/concentration
  • Sleep disturbances
  • Dizziness/loss of balance
  • Irritability-emotional disturbances
  • Feelings of depression
  • Seizures
  • Mood changes

Moderate to Severe TBI Symptoms

TBI results in permanent neurobiological damage that can produce lifelong deficits to varying degrees.  Moderate to severe brain injuries typically refer to injuries that have the following characteristics:

  • Moderate brain injury is defined as a brain injury resulting in a loss of consciousness from 20 minutes to 6 hours and a Glascow Coma Scale of 9 to 12. This is a 15-point scale used for estimating and categorizing the outcomes of brain injury.
  • Severe brain injury is defined as a brain injury resulting in a loss of consciousness of greater than 6 hours and a Glascow Coma Scale of 3 to 8.

Cognitive deficits including difficulties with:

  • Attention
  • Concentration
  • Distractibility
  • Memory
  • Speed of processing
  • Confusion
  • Impulsiveness
  • Language processing
  • “Executive Functions” (i.e. planning, initiating/inhibiting behavior, abstract thinking)

Speech and Language

  • Not understanding the spoken work (receptive aphasia)
  • Difficulty speaking and being understood (expressive aphasia)
  • Slurred speech
  • Speaking very fast or very slow
  • Problems reading and writing


  • Difficulties with interpretation of touch, temperature, movement, limb position and fine discrimination


  • Partial or total loss of vision
  • Weakness of eye muscles and double vision (diplopia)
  • Blurred vision
  • Intolerance of light (photophobia)


  • Decrease or loss of hearing
  • Ringing in the ears (tinnitus)
  • Increased sensitivity to sounds

Physical changes

  • Physical paralysis/spasticity
  • Chronic pain
  • Control of bowel and bladder
  • Loss of stamina
  • Appetite changes
  • Regulation of body temperature
  • Menstrual difficulties


  • Dependent behaviors
  • Emotional ability
  • Lack of motivation
  • Irritability
  • Aggression
  • Depression
  • Denial/lack of awareness

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