For most of human history, injuries to the head were left untreated and used to explain why a person was oddly different (“a mule kicked him”). There were no means to observe the brain, except during an autopsy, and even a view of the brain’s anatomy did not explain its function. This changed at the beginning of the 20th Century with publication of a German neurologist’s attempt to map areas of the brain by functions to which they were related.

During the century that followed, knowledge of the brain increased exponentially, aided by advanced neuro-imaging technology and laboratory studies. Treatments have also improved, to the point where many individuals who would have succumbed to a brain injury even 10 years ago are now surviving with medical intervention.

Individuals fortunate enough to be near a well-resourced trauma center or neurologic rehab unit when injured may emerge from a severe brain injury with remarkably preserved thinking and learning ability. Not everyone is so fortunate, and many of the students who are seen by ABE teachers may have been injured before advances in diagnosis and treatment were available.

It is also the case that for some at-risk populations, head trauma occurs so frequently, that it is almost ignored, obscured by behavioral issues. Among prison offenders, a much larger proportion (25-87%) are found with a diagnosable head injury compared with the general population (8.5%). However, whether a brain injury caused the person to engage in illegal behavior, the behavior caused the head injury (easy to conclude in the case of assault or gunshot wound), or whether a tendency toward high-risk behavior caused both.

Professionals working with young, at-risk men with head injuries often feel they are dealing with a double challenge — an individual with a history of disregarding consequences who is now even less likely to consider them.

For additional help in understanding TBI and related problems within the criminal justice system, consult these online resources.

Effects of Brain Injury

The effects of brain injury vary by whether the injury is generalized or focal and where in the brain the greatest damage has occurred.

Focal brain injuries are most clearly associated with a projectile injury, such as a gunshot or knife wound, and with a milder stroke or brain tumor. The extent of injury can be documented with a sensitive brain scan. For most individuals, effects on motor function, mood and behavior, and thinking and memory can also be predicted based on location of injury. However, for certain individuals the brain is organized differently — perhaps due to an early neuro-chemical imbalance or injury — and specific effects are unpredictable. Personal and family history of right-handedness and left-handedness may also play a role in determining how some parts of the brain are organized.

Experts typically rely on a good brain scan and neuropsychological testing to predict effects of a new brain injury based on location. In most instances they are correct; but someone following up on their predictions should remain open to the possibility that they will not apply to a particular individual. In this case, the individual must be relied on even more than usual to reveal effects, based on their behavior and reported experience.

One significant effect of focal brain injury is a language processing disorder classified as aphasia or dysphasia. It can occur alone or in combination with more generalized brain injury. This subject is addressed in the next chapter titled, “Aphasia”.

Generalized brain injuries occur most often when there is trauma to the head that causes whole-brain swelling and when a disease process or extensive stroke upsets the physiology or electrochemical processes in the brain. A prolonged period of repetitive, “grand-mal” seizures (status epilepticus, generalized) can also cause generalized injury. Long-term use of drugs and alcohol may eventually interfere broadly with brain functioning; but some functions are more sensitive to foreign substances than others — e.g., memory.

When the impact of injury is generalized, there are often focal impairments that are more severe. For example, a person sustaining a TBI with manifestations in multiple functional areas, may also display a more severe language processing disability classified as aphasia. Or a person post-stroke may demonstrate a range of difficulties with particular problems involving muscle control.

At this point, you are aware that effects of brain injury can vary considerably depending on the source of injury and how it interacts with the person’s own, perhaps unique brain organization. You are reminded that experts may not be able to provide all the answers you need to anticipate how a brain injury will affect a person’s ability to learn or even manage him- or herself in the classroom. You recognize that to some degree you are left on your own to work with your student with a brain injury to determine (a) What are the significant effects of injury? and (b) How can I adapt instructional materials, pacing, and environment to minimize effects of disability and make best use of remaining strengths?

This is all true. However, additional help is offered in the following section to help you anticipate what kinds of effects to be alert for. These will be addressed more specifically as instructional strategies are discussed in subsequent chapters.

Common Difficulties Following Brain Injury

Attention and Memory

A person’s interaction with the environment involves attention and memory. Information is received via any of the senses and given meaning by the brain, which draws on memory to interpret it. Effective responses to the environment, including any information targeted for learning requires:

  • Attention – paying attention to environmental stimuli
  • Concentration – focusing on giving meaning to what the senses are taking in
  • Information processing – interpreting a stimulus by drawing on past experience with it or something similar
  • Memory – drawing from a reservoir of prior experiences for help in interpreting a new stimulus

A person must be alert before any stimuli will register.

All aspects of attention and memory vary according to the type of stimuli the person is processing. Thus, a student may be more adept at attending to and processing visual information than verbal. Or he/she may work best when they can manually handle some form of what they are trying to learn. Verbal information transmitted in music may make more sense than the same information viewed on a printed page.

Individuals post brain injury may find that some kinds of stimuli are more difficult to process (i.e., pay attention to, remember) than others. A teacher will recognize these difficulties as differences by learning modality.

Processing Speed

When no impairments are noted in attention, concentration and/or memory, it typically takes more time after a brain injury for someone to absorb, interpret, and respond to information from the environment. In situations that require the person to respond quickly or reasonably fast, he or she can become overwhelmed with the rate at which information is coming to them. Group conversations may be difficult to follow for this reason. Reactions vary but often include anger, feeling discouraged, or shutting down. Staying engaged often depends on keeping the rate of stimulus presentation in sync with the person’s slower processing speed.

Sensory Acuity

Distinct areas of the brain are associated with each sense — sight, sound, touch, smell, taste and proprioception (balance, sense of oneself in space). Several of these are particularly vulnerable to trauma-induced injury, and effects may involve distortion, loss, or increased sensitivity to associated stimuli.

  • Sight – A common complaint following even a mild brain injury is blurry or double vision. These problems usually disappear in time. However, individuals may remain very sensitive to light. They typically wear dark glasses even indoors. If exposed to too much light, they can become irritable or refuse to participate.
  • Sound – Sensitivity to sound may also persist especially at high decibels, and these can precipitate a sudden outburst on exposure. For someone with a brain injury, high-pitched sounds can be piercingly painful.
  • Smell and taste – When an impact to the head is taken at the back or front of the head, loss of smell often follows, and with it diminished taste. Sometimes a mild concussion is diagnosed based on reduced smell alone in the absence of other symptoms.
  • Proprioception – It is not uncommon after a head injury for individuals to experience dizziness or a sense the room is moving. Some find they cannot perform athletic activities with the same skill as before, because their balance is altered. These experiences may resolve in time or remain. Ringing in the ears may persist after dizziness is gone.

Sensory loss should be evaluated and confirmed by a medical professional.

Executive Functioning

This class of brain activities is diverse, but all of its features have in common two requirements: goal-oriented deliberation and a self-observing eye. Normal executive functions direct a person’s actions in response to what he or she experiences or wants to experience. They include:

  • Reasoning ability and insight
  • Judgment and ability to anticipate consequences
  • Problem solving
  • Planning and organizing
  • Initiation
  • Monitoring and evaluating effects of ones behavior
  • Adaptability

When executive functions are impaired as a result of brain injury one or both of the following kinds of effects may be observed (if both, then alternately):

  1. Poor initiation – The person appears unmotivated. Even though they sincerely want to achieve a particular goal, they are unable to begin the action necessary to achieve it. Repeated reminders do no good. This person may also appear unaware and unconcerned about failure to act. Actions that are taken may be perseverative (repeated over and over)with little apparent need to move on.
  2. Disinhibition – Here judgment and problem solving are impaired and consequences are not anticipated. Action is impulsive. The person may regret the consequences later but appears to forget when an opportunity to repeat the mistake reveals itself again. This set of symptoms can coexist with thinking rigidity and impatience, making it hard to teach problem solving and self management.

Individuals whose injury produces such behaviors are the most frustrating to work with, and it’s tempting to blame them and get angry. It’s difficult not to take their behavior personally. But because the individual often lacks full self-awareness, he or she may be only puzzled or annoyed by another’s anger or impatience, not understanding his or her own part in causing it.

Even when the injury is mild and self awareness is intact, individuals may struggle to get or keep themselves organized. Thus, they may appear forgetful when memory is not a problem, because they didn’t assemble or couldn’t find what they needed to bring, for example, or they’re habitually late.


The effort it takes to focus attention, remember, tune out unwanted sensory stimuli, and organize oneself for action requires much more energy than normal, following a brain injury. Thus, even when someone appears fully recovered cognitively following concussion, the fatigue typically remains.

Fatigue can express itself as resistance, irritability, or exacerbation of other learning difficulties, making it a compounding factor when present.

For young people or persons accustomed to an active lifestyle, it is tempting to try to maintain a customary level of activity even when their mind and body are ill-equipped to sustain the effort. The student with a brain injury who is spending the day at work or with friends or caring for family members may be unusually tired when they arrive for class in the evening. But they may resist any suggestion they should undertake a less demanding schedule.

Emotional, Behavioral, and Social Effects

Some noticeable behavioral effects of executive dysfunction were described above. Post brain injury, a person may say things that are socially inappropriate or too loud, because he or she is not monitoring their behavior for consideration or courtesy. In some cases, family and friends point out a changed personality, which can also be attributed to changes in executive function.

Effects on emotion often stem from frustration and loss of self esteem following a brain injury, when the person sees they can no longer do or be what they were accustomed to. Depression is common along with irritability. Frustration and anger may be quicker and more intense than normal when the person finds it harder to do something that was once easy. Impulsive behaviors are common, and physical acting out is a risk.

Among persons whose behavior is predominately normal, there is a tendency to be more self-centered, less flexible, and stuck — on routines, a story they tell over and over, or another repetitive activity.

Interpersonal Relationships

Depending on the severity of injury, self-centeredness may interfere with developing fully reciprocal relationships. However, often the sense of humor is retained or a new ability to laugh is acquired; and individuals with brain injuries can enjoy and contribute to social activities.

Maintaining pre-injury relationships is often difficult. One member of a pair may find him- or herself in an unwelcome parent role as the other becomes more dependent. Friends often drift away, as a person becomes less attuned to nuance and jargon in conversation and finds it harder to keep up with the rapid back and forth. Loss of confidence post brain injury is visible and uncomfortable to others. And often the individual is unable to resume former activities. Thus, social segregation is common.

When communication is handicapped by word-finding difficulties and other aspects of aphasia (next chapter), the challenge of social integration is even greater.

Physical Disability

Whether brain injury is traumatically induced or not, it is often accompanied by changes in motor function and neuro-muscular control. Bleeding, obstructive clots, or a tumor in the brain may occur in primary motor or sensory areas or near nerve tracks that relay messages to nerves and muscles. Forces that accompany traumatic injuries may sever or damage these important connections.

Effects include changes in sensory perception or processing, loss of movement, and difficulty speaking and swallowing. They may also include changes in balance and spatial orientation. Effects are often unilateral, meaning they affect one side of the body solely or more severely.

For spinal-cord-injured persons and persons badly injured in motor vehicle accidents or combat, wound repair may take precedence over attending to a brain injury when there is no visible evidence of it initially. As a consequence, brain injuries may not be treated during the early stages of recovery when the greatest impact on recovery can be made.

An injured person and family/friends may also focus so much on a physical disability that they remain unaware for a while of changes in thinking and memory or personality, for example. Some emergency events, such as heart attack, often affect the brain as well (due to temporary loss of oxygen); but the focus is on the heart.

In addition to injury, brain lesions can be caused by infection, toxic exposure, problems with the immune system, and changes in organ function or glands; and all of these generally produce physical effects, as well.

Speech and Language

Features of attention and memory come into play when an individual is required to process symbolic systems — i.e., information presented in the form of letters and words or numbers and operational symbols. However, if speech and language are impaired, the problem likely has less to do with focusing attention than with the particular subject matter they are trying to process.

Reading, Math Operations

Reduced ability in these areas is usually attributed to injury of one or more related brain functions. For example, the problem may be at the encoding level, where symbols do not appear as they should. Or it may be affected by loss of memory for vocabulary or math operations. Alternatively, it may be a connectivity problem — meaning learned information is present and symbols are perceived correctly, but the nerve tracts connecting printed symbols to memory are destroyed or damaged. Without connectivity, the person cannot use prior learning to make sense of what he or she currently sees. Thus, reading and/or math problem solving is affected. Understanding the source of the problem and improving these academic skills will benefit from assessment by a speech therapist.

Speech, Written Expression

Often, if a person post-brain injury has difficulty responding to symbolic systems, she or he will also have difficulty expressing them, but not always. A common exception is the individual, post stroke, whose motor speech is affected but not their ability to process language apart from the act of speaking. Thus, they can often write out what they want to say, even if the words are not clearly spoken. Following a traumatic brain injury, some individuals have difficulty with “word finding,” or retrieving the words they intend to use to express a thought. This problem typically affects the use of nouns (names of people, places, and things) more than other parts of speech. Their thoughts may be well formed and sensible, but they lack the means of communicating them in speech or writing. The challenge, when this problem appears, is to accurately recognize what a person knows when they have difficulty expressing it.


The person’s pre-injury intelligence is a function of genetic endowment and all of the learning that has taken place prior to injury. A significant brain injury in adulthood or late teens does not so much destroy that intelligence but make it harder to access. This result is due to the loss of neurons that store information but also the connections necessary to relate question to answer or intention to execution.

Individuals with a diagnosed brain injury may do very well on individual tests of intelligence but fail to maintain employment because of impaired executive functions. Some may do poorly post-injury on verbal tests because they have difficulty finding and expressing what they know in words. Others may do well on untimed, verbal tests and poorly on timed tests requiring speed of information processing.

Thus, it may be difficult to obtain an accurate measure of a person’s intelligence or to predict accurately how they will behave in a learning situation based on intelligence test scores. The best thing to do is give them the benefit of the doubt.

For individuals injured as children, their ability to acquire learning and make the most of experience may have been curtailed by effects of injury. In this case, intelligence test scores may represent current, functional intelligence and provide a fairly accurate basis on which to predict success in learning.

Academic Skills

Unless the application of previously acquired academic skills is hindered by impairments to attention and memory, the impact of brain injury on academic skills will primarily reflect the amount of productive schooling a person obtained prior to injury. If the individual read at a 5th grade level, they are likely to have difficulty reading complex paragraphs now. Vocabulary, computational skills, and facts learned in school should remain as they were, allowing for normal forgetting. Problem solving skills will vary with effects on executive functions.

Issues will be encountered at the speed with which a person can process information (e.g., resulting in slower decoding and writing) and the feelings and behavior that accompany greater difficulty in learning. The individual may also respond adversely to the environment when sensory sensitivity is present or he/she is vulnerable to distraction.

Impact of Injury Severity

Because an injury to the brain may affect behavior in unique and unpredictable ways, it is risky to generalize. But on average, the following observations can be made about several kinds of brain injury:

Concussion or Mild TBI

This is typically a generalized injury by which immediate effects are reduced attention and concentration, fatigue, and often dizziness, headache, visual distortions and/or sensory sensitivity (to light and/or sound). Individuals may feel depressed, anxious, irritable, snap at others, and sleep fitfully. For most but not all individuals, symptoms after the first concussion become milder or disappear over a few days to a few months.

Subsequent concussions produce similar symptoms that do not typically dissolve so quickly. After multiple concussions, some effects become permanent. They may be as mild as permanent ringing in the ears and sensitivity to bright lights, or more handicapping — such as difficulty concentrating on and thus remembering new information, and fatigue associated with sustained mental effort. Occasionally, repetitive concussions produce persistent changes in mood and behavior. Longer intervals between concussions are associated with less harmful effects.

Combat-Related TBI

The context is significant, because it is associated with psychological factors that confound diagnosis, treatment, and recovery of brain injury.

No visible wound may exist on the head or even elsewhere on the body. The force of a nearby explosion may have jolted the soft tissue of the brain the same as a sudden impact, causing shearing and bruising. Effects can include difficulties with attention and memory, behavior changes, and changes in sensory acuity among others. As for concussions, anxiety, depression, and irritability may follow.

If the veteran was not unconscious after an explosion, he or she will likely remember all of the events before, during and after an attack. Given the life threatening situation and certain symptoms associated with psychological trauma, a diagnosis of Post-Traumatic Stress Disorder (PTSD) may be applied. This disorder produces considerable anxiety, poor sleep, hyper-alertness, and fear in certain situations. Such experiences serve as powerful internal distracters making it hard to concentrate and thus remember what one is supposed to be attending to.

Either form of trauma creates a powerful sense of loss in one who no longer believes they are the competent person they once were. Depression often ensues. The behavioral manifestations of either kind of trauma can drive people away, isolate the person, and deepen depression. It is harder to treat brain injuries or even assess them properly in the presence of PTSD.

Domestic Violence

The head, face and neck are by far the most frequent targets of assault in families and domestic partnerships. The head may be struck with an object, fist, gunshot or knife or thrust against the wall. Sudden and severe jolting may injure the brain when the person is shaken or knocked down; and restriction of the airway may deprive brain cells of oxygen for a time. Most victims of assault are hurt repeatedly, with cumulative effects.

Among the victims of intimate partner assault, 85% are women and 15% are men. About one in five female high school students in one study reported physical or sexual abuse by a dating partner. No demographic group is spared.

Because of a close relationship and, often, dependency between victim and abuser, there are emotional and psychological consequences of battering, as well. And, as for combat-related TBI, symptoms co-mingle and exacerbate each other. Symptoms such as difficulty concentrating, solving problems, and making decisions, memory problems, headaches, depression and feeling overwhelmed can accompany both TBI and severe emotional trauma. Add to these the persistent stress of remaining in a threatening relationship, and the situation can be severely disabling.

For more mental health information and resources go to the Mental Health Chapter of this website.


Brain injury caused by stroke is associated with loss of oxygen to the brain. Depending on the size and location of the area that is deprived, effects may be focal or more general. For example, a stroke located more peripherally in the brain will likely affect specific functions. One located central to the brain, where a great deal of information exchange and regulation occurs, may be demonstrated more broadly.

Strokes often affect motor functions in some respect — e.g., speech, swallowing, facial expressions and arm/leg mobility. They may increase emotionality and influence mood. Psychiatric disorders can be blamed on a stroke but not typically. Higher order reasoning and executive functions are often saved. Speed of information processing is typically slowed, and adjustment to disability frequently a challenge.

What is important to remember is that for all the dramatic losses experienced when sustaining an acquired brain injury, many or most of their pre-injury capabilities are preserved. These offer a foundation for learning, with adjustments for any handicapping conditions.