Frontal Lobe Brain Injuries

The frontal lobe of the brain (behind the forehead) is the largest of the four lobes of the brain. The frontal lobe controls “executive functions,” such as memory, thinking, reasoning, information processing, organizing, planning, decision making and judgment. The back part of the frontal lobe controls voluntary movement. The frontal lobe is the “gatekeeper” of one’s personality, controlling judgment, inhibition, and an individual’s emotional traits

The frontal lobes are considered our emotional control center and home to our personality. There is no other part of the brain where lesions can cause such a wide variety of symptoms (Kolb & Wishaw). The frontal lobes are involved in motor function, problem solving, spontaneity, memory, language, initiation, judgment, impulse control, and social and sexual behavior. The frontal lobes are extremely vulnerable to injury due to their location at the front of the cranium, proximity to the sphenoid wing (a sharp area of bone inside the skull) and their large size. MRI studies have shown that the frontal area is the most common region of injury following mild to moderate traumatic brain injury (Levin et al.).

There are important asymmetrical differences in the frontal lobes. The left frontal lobe is involved in controlling language related movement, whereas the right frontal lobe plays a role in non-verbal abilities. Some researchers emphasize that this rule is not absolute and that with many people, both lobes are involved in nearly all behavior. 

Injury to the frontal lobes often results in disturbance of motor function, a condition typically characterized by loss of fine movements and strength of the arms, hands and fingers. Complex chains of motor movement also seem to be controlled by the frontal lobes. Patients with frontal lobe damage exhibit little spontaneous facial expression, which points to the role of the frontal lobes in facial expression, as well as with interpreting the facial expression of other people. Broca’s Aphasia, or difficulty in speaking, has been associated with frontal damage.  Similarly, frontal lobe injuries impact the ability to interpret the speech of other people.

An interesting phenomenon of frontal lobe damage is the insignificant effect it can have on traditional IQ testing. Researchers believe that this may have to do with IQ tests typically assessing convergent rather than divergent thinking. Frontal lobe damage seems to have an impact on divergent thinking, or flexibility and problem solving ability. There is also evidence showing lingering interference with attention and memory even after good recovery from a TBI (Stuss et al., 1985).

Frontal lobe injuries can cause significant changes in personality.  Personality changes are one type of behavioral changes that are known to have a higher rate of permanency than cognitive changes, and can cause devastating effects in a person's professional and personal life. One area often associated with frontal damage is that of “behavioral sponteneity.” Kolb & Milner found that individual with frontal damage displayed fewer spontaneous facial movements, and dependent upon the area of injury either spoke fewer words (left frontal lesions) or spoke excessively (right frontal lesions).

One of the most common characteristics of frontal lobe damage is difficulty in interpreting feedback from the environment. Perseverating on a response (Milner, 1964), risk taking, and non-compliance with rules (Miller, 1985), and impaired associated learning (using external cues to help guide behavior) (Drewe, 1975) are a few examples of this type of deficit.

The frontal lobes are also thought to play a part in our spatial orientation, including our body’s orientation in space (Semmes et al., 1963).

One of the most common effects of frontal lobe damage can be a dramatic change in social behavior. A person’s behavior and personality can undergo significant changes after an injury to the frontal lobes. There are some differences in the left versus right frontal lobes in this area. One example is that Left frontal lobe damage usually manifests as pseudodepression and right frontal lobe damage often presents as pseudopsychopathic.

Sexual behavior can also be effected by frontal lesions. Orbital frontal damage can introduce abnormal sexual behavior, while dorolateral lesions may reduce sexual interest (Walker and Blummer, 1975).  Similarly, left frontal lobe damage often results in decreased or no libido, whereas right frontal damage has been associated with nyphomania. For this reason, some of the earliest legal cases involving a traumatic brain injury were misclassified as psychological injury cases. One of the earliest legal cases on this issue was a case of nymphomania caused by a right frontal lobe injury resulting from a streetcar crash in San Francisco; Gloria Sykes v. San Francisco Municipal Railway.

Some common tests for frontal lobe function are: Wisconsin Card Sorting (response inhibition); Finger Tapping (motor skills); Token Test (language skills).

Frontal lobe injuries can cause the following symptoms:

• Reduced drive
• Mood changes (Emotionally Labile)
• Personality changes
• Memory deficits
• Impaired information processing speed
• Reduced judgment
• Increased impulsivity and disinhibition
• Uncharacteristic lewdness and cursing
• Difficulty with problem solving
• Loss of flexibility in thinking
• Problems with interpersonal behavior
• Loss of spontaneity in interacting with others
• Reduced attention
• Inability to focus on task (Attending)
• Persistence of a single thought (Perseveration)
• Inability to express language (Broca’s Aphasia)
• Increased aggression
• Inability to plan properly and execute those plans (Executive Function)
• Increased disorganization
• Inability to plan a sequence of complex movements needed to complete multi-stepped tasks (Sequencing)
• Altered sense of smell (Anosmia)
• Loss of simple movement of various body parts (Paralysis)
• Diminution of attention to personal appearance and hygiene
• Lack of organization
• Obsessive collecting ("forced collectionism") and hoarding. (Frontoorbital injury)

The frontal lobes are the largest area of the brain and are composed of several important neurological structures.  In some cases, a neurologist can isolate one or more of these areas as being injured during a traumatic brain injury. 

• Prefrontal Cortex (PFC): As the center for higher-order thinking, an injury to this area will cause difficulties with planning, memory, and rational thought.
  • Dorsolateral Prefrontal Cortex (DLPFC) We see frequent injuries to this area in our traumatic brain injuries cases.  Executive function deficits is one symptom of an injury to the Dorsolateral Prefrontal Cortex.
  • Ventromedial Prefrontal Cortex (vmPFC): Crucial for coping with the emotion of fear. Damage to the Ventromedial Prefrontal Cortex impairs the ability to process safety and regulate fear.  This can aggravate a person who has sustained both a TBI and PTSD in the same event.
• Anterior Cingulate Cortex (ACC): Injury to the Anterior Cingulate Cortex can impact emotional regulation and impulse control.
• Orbitofrontal Cortex (OFC):  The Orbitofrontal Cortex is particularly vulnerable to trauma. Damage to the Orbitofrontal Cortex leads to behavioral changes including personality changes, impulsivity, and emotional instability.  This can cause significant damage to a person's work life and personal life, by damaging relationships with family, friends, co-workers and other people.  It can also lead to financial impacts and criminal behavior.
• Inferior, Superior and Medial Frontal regions: Specific regions like the right medial orbitofrontal, superior frontal, and caudal middle frontal areas show reduced gray matter volume in cases of trauma.

Learn more about left frontal lobe injuries.

Learn more about right frontal lobe injuries.

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