Overview
What is a Brain Injury?
A brain makes it possible to think, communicate, act, behave, move about and create. A brain injury can impair cognition, physical functions and psychosocial behavior. These changes causes stress in relationships, education and employment. As an educator, the more you know and understand about brain injuries and their consequences, the more you will be able to help your student.
There are two types of brain injuries. Traumatic brain injury (TBI) and acquired brain injury. Below is an explanation of both.
Traumatic Brain Injury
An estimated 10 million people are affected by traumatic brain injury (5.3 million) and strokes (4.7 million). Traumatic brain injuries and strokes are the second most prevalent injury and disability in the United States. Also, more than 1.4 million people in the United States annually sustain a traumatic brain injury. About 5,000 Minnesotans sustain a TBI annually. The three main incidence groups are 0-4 year olds, 15-19 year olds and 65 and older. Falls and motor vehicle crashes are the main causes of TBI.
The Brain Injury Association of America defines traumatic brain injury as an insult to the brain, not degenerative or congenital, but caused by external physical force. The force produces a diminished or altered state of consciousness, which results in an impairment of cognitive abilities and/or physical function. It can also result in the disturbance of behavioral or emotional functioning. These impairments may be either temporary or permanent and cause partial or total functional disability or psychosocial maladjustment.
A traumatic brain injury (TBI) is defined by the Centers for Disease Control (CDC) as a blow or jolt to the head or a penetrating head injury that disrupts the function of the brain. The severity of such an injury 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 result in short or long term problems with independent function.
Causes of Traumatic Brain Injury include:
- Motor vehicle crashes
- Falls
- Gunshot wounds
- Sports Injuries
- Workplace injuries
- Shaken baby injuries
- Child abuse
- Domestic violence
- Military actions
- Other injuries caused by trauma
Acquired Brain Injury
The definition of an acquired brain injury is more comprehensive and includes not only injuries caused by the trauma, but also internal insults to the brain. An acquired brain injury occurs after birth and is not hereditary, congenital or degenerative. The injury commonly results in a change in neuronal activity, which affects physical, metabolic and functional activity of the cell.
Causes of Acquired Brain Injury include:
- Traumatic brain injury
- Tumors
- Blood clots
- Strokes
- Seizures
- Toxic exposures (e.g. substance abuse, ingestion of lead, volatile agents)
- Infections (encephalitis, meningitis)
- Metabolic disorders (insulin shock, diabetic coma, liver and kidney disease)
- Neurotoxic poisoning (airway obstruction, strangulation, cardiopulmonary arrest, carbon monoxide poisoning, drowning)
- Lack of oxygen to the brain
The educational consequences are similar for traumatic and acquired brain injury. Both brain injuries effect the physical, cognitive, communication, emotional and social functions of the student.
Brain Anatomy
There are a variety of terms used to describe the types of injuries and the many structures within the brain.
Our brains control everything about us: who we are, what we do and why we do it. Functions are assigned to the various regions of the brain and lead to more or less efficiency in performance of tasks (cognitive and physical).
The lobes include Occipital, Parietal, Temporal, and Frontal.
The cerebellum is the underside portion of the brain whose function is balance, coordination and motor skills.
The brain stem controls breathing, heart rate, sleep patterns, attention/concentration.
The occipital lobe is mostly devoted to vision and the parietal lobe is considered the sensate region of the brain.
Traumatic brain injury involves injury to the frontal lobe due to the mechanism of the fragile brain slamming into the hard skull during the original trauma. Many higher order executive functions are controlled by the frontal lobe: initiation, problem solving, behavior regulation, judgment, personality, language expression, social perception and mental flexibility.
Our limbic system, which is located behind the temporal lobes, controls our drives (fight/flight, hunger, sexual) plus emotional perception, and memory organization/recall.
The temporal lobe controls aspects of memory, hearing, language processing and organization/sequencing.
Brain Functions and Map (an excerpt) By Robert P. Lehr Jr., PhD.D.
The brain has many parts, including the cerebral cortex, brain stem, and cerebellum. By listing some of the functions of each part of the brain, we will provide an overview of what problems occur after [traumatic brain] injury.
It is important to understand that the brain functions as a whole by interrelating its component parts. The injury may only disrupt a particular step of an activity that occurs in a specific part of the brain. The interruption of that activity at any particular step, or out of sequence, can reveal the problems associated with the injury.
Below is a list of functions and deficits or problems revealed when injury occurs at particular locations. The terms in parenthesis are the professional terms used to describe the deficit. Please refer to the Brain Map at www.neuroskills.com/tbi/brain.shtml for more details and related references.
Cerebral Cortex
Frontal Lobe: Located at the most anterior point, right under the forehead. Functions:
- How we know what we are doing within our environment (consciousness)
- How we initiate activity in response to our environment
- Judgments we make about what occurs in our daily activities
- Controls our emotional response
- Controls our expressive language
- Assigns meaning to the words we choose
- Involves word associations
- Memory for habits and motor activities
Observed Problems:
- Loss of simple movement of various body parts (paralysis)
- Inability to plan a sequence of complex movements needed to complete multi-stepped tasks, such as making coffee (sequencing)
- Loss of spontaneity in interacting with others
- Loss of flexibility in thinking
- Persistence of a single thought (perseveration)
- Inability to focus on task (attending)
- Mood changes (emotionally labile)
- Changes in social behavior
- Changes in personality
- Difficulty with problem solving
- Inability to express language (Broca’s Aphasia)
Parietal Lobe: Located near the back and top of the head. Functions:
- Location for visual attention
- Location for touch perception
- Goal directed voluntary movements
- Manipulation of objects
- Integration of different senses that allows for understanding a single concept
Observed Problems:
- Inability to attend to more that one object at a time
- Inability to name an object (anomia)
- Inability to located the words for writing (agraphia)
- Problems with reading (alexia)
- Difficulty with drawing objects
- Difficulty in distinguishing left from right
- Difficulty with doing mathematics (dyscalculia)
- Lack of awareness of certain body parts and /or surrounding space (apraxia) that leads to difficulties in self-care
- Inability to focus visual attention
- Difficulties with eye and hand coordination
Occipital Lobes: Located at the most posterior point, at the back of the head. Functions:
- Vision
Observed Problems:
- Defects in vision (visual field cuts)
- Difficulty with locating objects in environment
- Difficulty with identifying colors (color agnosia)
- Production of hallucinations
- Visual illusions-inaccurately seeing objects
- Word blindness-inability to recognize words
- Difficulty in recognizing drawn objects
- Inability to recognize the movement of an object (movement agnosia)
- Difficulties with reading and writing
Temporal Lobes: Located at the side of head, above the ears. Functions:
- Hearing ability
- Memory acquisition
- Some visual perceptions
- Categorization of objects
Observed Problems:
- Difficulty in recognizing faces (prosopagnosia)
- Difficulty in understanding spoken words (Wernicke’s Aphasia)
- Disturbance with selective attention to what we see and hear
- Difficulty with identification of, and verbalization about objects
- Short-term memory loss
- Interference with long-term memory
- Increased or decreased interest in sexual behavior
- Inability to categorize objects (categorization)
- Right lobe damage can cause persistent talking
- Increased aggressive behavior
Brain Stem: Located deep in the brain, leading to the spinal cord. Functions:
- Breathing
- Heart Rate
- Swallowing
- Reflexes to seeing and hearing (startle response)
- Controls sweating, blood pressure, digestion, temperature (autonomic nervous system)
- Affects level of alertness
- Ability to sleep
- Sense of balance (vestibular function)
Observed Problems:
- Decreased vital capacity in breathing, important for speech
- Swallowing food and water (dysphagia)
- Difficulty with organization/perception of the environment
- Problems with balance and movement.
- Dizziness and nausea (vertigo)
- Sleeping difficulties (Insomnia, sleep apnea)
Cerebellum: Located at the base of the skull. Functions:
- Coordination of voluntary movement
- Balance and equilibrium.
- Some memory for reflex motor acts
Observed Problems:
- Loss of ability to coordinate fine movements
- Loss of ability to walk
- Inability to reach out and grab objects
- Tremors
- Dizziness (vertigo)
- Slurred Speech (scanning speech)
- Inability to make rapid movements
Please go to www.neuroskills.com/tbi/brain.shtml for the complete article. You will also find a brain map where you can learn about each area of the brain and its function. In addition you can preview video clips of various brain injuries.