| Frontal lobe disorder | |
|---|---|
 | |
| Illustration of lateral view of the right side of thebrain showing thefrontal lobe, otherlobes of the brain, and thecerebellum | |
| Specialty | Neurology, psychiatry |
| Symptoms | Tremor, dystonia[1] |
| Causes | Closed head injuries[2] |
| Diagnostic method | Neuropsychological test[3] |
| Treatment | Speech therapy, supportive care[4] |
Frontal lobe disorder, alsofrontal lobe syndrome, is an impairment of thefrontal lobe of thebrain due to disease orfrontal lobe injury.[5] The frontal lobe plays a key role inexecutive functions such as motivation, planning, social behaviour, and speech production. Frontal lobe syndrome can be caused by a range of conditions including head trauma, tumours,neurodegenerative diseases,neurodevelopmental disorders, neurosurgery andcerebrovascular disease. Frontal lobe impairment can be detected by recognition of typicalsigns and symptoms, use of simple screening tests, and specialist neurological testing.[3][6]
The signs and symptoms of frontal lobe disorder can be indicated bydysexecutive syndrome[7] which consists of a number of symptoms which tend to occur together.[8] Broadly speaking, these symptoms fall into three main categories; cognitive (movement and speech), emotional or behavioral. Although many of these symptoms regularly co-occur, it is common to encounter patients who have several, but not all of these symptoms. This is one reason why some researchers are beginning to argue that dysexecutive syndrome is not the best term to describe these various symptoms. The fact that many of the dysexecutive syndrome symptoms can occur alone has led some researchers[9] to suggest that the symptoms should not be labelled as a "syndrome" as such. Some of the latest imaging research[10] on frontal cortex areas suggests that executive functions may be more discrete than was previously thought. Signs and symptoms can be divided as follows:[1]
Emotional
Behavioral
Language signs
The causes of frontal lobe disorders can beclosed head injury. An example of this can be from an accident, which can cause damage to the orbitofrontal cortex area of the brain.[2]
Cerebrovascular disease may cause astroke in the frontal lobe.Tumours such asmeningiomas may present with a frontal lobe syndrome.[11] Frontal lobe impairment is also a feature ofAlzheimer's disease, andfrontotemporal dementia.[1]
The pathogenesis of frontal lobe disorders entails various pathologies, some are as follows:
The frontal lobe contains the precentral gyrus and prefrontal cortex and, by some conventions, the orbitofrontal cortex. These three areas are represented in both the left and the right cerebral hemispheres. Theprecentral gyrus orprimary motor cortex is concerned with the planning, initiation and control of fine motor movements dorsolateral to each hemisphere.[15] The dorsolateral part of the frontal lobe is concerned with planning, strategy formation, and otherexecutive functions. The prefrontal cortex in the left hemisphere is involved withverbal memory while the prefrontal cortex in the right hemisphere is involved inspatial memory. The left frontal operculum region of the prefrontal cortex, orBroca's area, is responsible for expressive language, i.e. language production. Theorbitofrontal cortex is concerned with response inhibition, impulse control, and social behaviour.[4]
The diagnosis of frontal lobe disorder can be divided into the following three categories:
Frontal lobe disorders may be recognized through a sudden and dramatic change in a person'spersonality, for example with loss of social awareness, disinhibition, emotional instability, irritability or impulsiveness. Alternatively, the disorder may become apparent because of mood changes such asdepression,anxiety or apathy.[1]
Onmental state examination a person withfrontal lobe damage may show speech problems, with reduced verbal fluency.[4] Typically the person is lacking in insight and judgment, but does not have marked cognitive abnormalities or memory impairment (as measured for example by themini-mental state examination).[16] With more severe impairment there may beecholalia ormutism.[17]Neurological examination may showprimitive reflexes (also known as frontal release signs) such as thegrasp reflex.[18]Akinesia (lack of spontaneous movement) will be present in more severe and advanced cases.[19]
A range ofneuropsychological tests are available for clarifying the nature and extent of frontal lobe dysfunction. For example,concept formation and ability to shift mental sets can be measured with theWisconsin Card Sorting Test, planning can be assessed with the Mazes subtest of theWISC.[3]Frontotemporal dementia shows up asatrophy of the frontal cortex onMRI.[20] Frontal impairment due to head injuries, tumours or cerebrovascular disease will also appear on brain imaging.[4]
In terms of treatment for frontal lobe disorder, there is none, general supportive care is given, also some level of supervision could be needed. The prognosis will depend on the cause of the disorder, of course. A possible complication is that individuals with severeinjuries may be disabled, such that, acaregiver may be unrecognizable to the person.[5] Another aspect of treatment of frontal lobe disorder isspeech therapy. This type of therapy might help individuals with symptoms that are associated withaphasia anddysarthria.[4]
Phineas Gage, who sustained a severe frontal lobe injury in 1848, has been called a case of dysexecutive syndrome. Gage's psychological changes are almost always exaggerated – of the symptoms listed, the only ones Gage can be said to have exhibited are "anger and frustration", slight memory impairment, and "difficulty in planning".[21]
In December 2005, at hisDover Road flat in Singapore, 44-year-old caretakerMohammad Zam Abdul Rashid attacked and battered his 38-year-old wife Ramona Johari (a production operator) to death after he accused her of getting close to a colleague. Mohammad Zam was originally charged with murder but after he was found to be suffering from frontal lobe syndrome, which went undiagnosed prior to the murder and had affected his mental responsibility at the time of the killing, Mohammad Zam was convicted of a reduced charge of manslaughter and hence sentenced tolife imprisonment.[22] The diagnosis of frontal lobe syndrome in this homicide case generated public discussions about the disorder.[23]
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