Frontal lobe disorder | |
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Illustration of lateral view of the right side of the brain showing the frontal lobe, other lobes of the brain, and the cerebellum | |
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, also frontal lobe syndrome, is an impairment of the frontal lobe of the brain due to disease or frontal lobe injury. [5] The frontal lobe plays a key role in executive 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 and cerebrovascular disease. Frontal lobe impairment can be detected by recognition of typical signs and symptoms, use of simple screening tests, and specialist neurological testing. [3] [6]
The signs and symptoms of frontal lobe disorder can be indicated by dysexecutive 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 be closed 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 a stroke in the frontal lobe. Tumours such as meningiomas may present with a frontal lobe syndrome. [11] Frontal lobe impairment is also a feature of Alzheimer's disease, and frontotemporal 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. The precentral gyrus or primary 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 other executive functions. The prefrontal cortex in the left hemisphere is involved with verbal memory while the prefrontal cortex in the right hemisphere is involved in spatial memory. The left frontal operculum region of the prefrontal cortex, or Broca's area, is responsible for expressive language, i.e. language production. The orbitofrontal 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's personality, for example with loss of social awareness, disinhibition, emotional instability, irritability or impulsiveness. Alternatively, the disorder may become apparent because of mood changes such as depression, anxiety or apathy. [1]
On mental state examination a person with frontal 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 the mini-mental state examination). [16] With more severe impairment there may be echolalia or mutism. [17] Neurological examination may show primitive reflexes (also known as frontal release signs) such as the grasp reflex. [18] Akinesia (lack of spontaneous movement) will be present in more severe and advanced cases. [19]
A range of neuropsychological 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 the Wisconsin Card Sorting Test, planning can be assessed with the Mazes subtest of the WISC. [3] Frontotemporal dementia shows up as atrophy of the frontal cortex on MRI. [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 severe injuries may be disabled, such that, a caregiver may be unrecognizable to the person. [5] Another aspect of treatment of frontal lobe disorder is speech therapy. This type of therapy might help individuals with symptoms that are associated with aphasia and dysarthria. [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 his Dover Road flat in Singapore, 44-year-old caretaker Mohammad 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 to life imprisonment. [22] The diagnosis of frontal lobe syndrome in this homicide case generated public discussions about the disorder. [23]
Brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating trauma-induced damage.
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere. It is parted from the parietal lobe by a groove between tissues called the central sulcus and from the temporal lobe by a deeper groove called the lateral sulcus. The most anterior rounded part of the frontal lobe is known as the frontal pole, one of the three poles of the cerebrum.
Hypergraphia is a behavioral condition characterized by the intense desire to write or draw. Forms of hypergraphia can vary in writing style and content. It is a symptom associated with temporal lobe changes in epilepsy and in Geschwind syndrome. Structures that may have an effect on hypergraphia when damaged due to temporal lobe epilepsy are the hippocampus and Wernicke's area. Aside from temporal lobe epilepsy, chemical causes may be responsible for inducing hypergraphia.
Frontotemporal dementia (FTD), also called frontotemporal degeneration disease or frontotemporal neurocognitive disorder, encompasses several types of dementia involving the progressive degeneration of the brain's frontal and temporal lobes. FTD is the second most prevalent type of early onset dementia after Alzheimer's disease. Men and women appear to be equally affected. FTD generally presents as a behavioral or language disorder with gradual onset. Signs and symptoms tend to appear in late adulthood, typically between the ages of 45 and 65, although it can affect people younger or older than this. Currently, no cure or approved symptomatic treatment for FTD exists, although some off-label drugs and behavioral methods are prescribed.
Bálint's syndrome is an uncommon and incompletely understood triad of severe neuropsychological impairments: inability to perceive the visual field as a whole (simultanagnosia), difficulty in fixating the eyes, and inability to move the hand to a specific object by using vision. It was named in 1909 for the Austro-Hungarian neurologist and psychiatrist Rezső Bálint who first identified it.
Orientation is a function of the mind involving awareness of three dimensions: time, place and person. Problems with orientation lead to disorientation, and can be due to various conditions. It ranges from an inability to coherently understand person, place, time, and situation, to complete orientation.
Disinhibition, also referred to as behavioral disinhibition, is medically recognized as an orientation towards immediate gratification, leading to impulsive behaviour driven by current thoughts, feelings, and external stimuli, without regard for past learning or consideration for future consequences. It is one of five pathological personality trait domains in certain psychiatric disorders. In psychology, it is defined as a lack of restraint manifested in disregard of social conventions, impulsivity, and poor risk assessment. Hypersexuality, hyperphagia, substance abuse, money mismanagement, frequent faux pas, and aggressive outbursts are indicative of disinhibited instinctual drives.
In neurology, semantic dementia (SD), also known as semantic variant primary progressive aphasia (svPPA), is a progressive neurodegenerative disorder characterized by loss of semantic memory in both the verbal and non-verbal domains. However, the most common presenting symptoms are in the verbal domain. Semantic dementia is a disorder of semantic memory that causes patients to lose the ability to match words or images to their meanings. However, it is fairly rare for patients with semantic dementia to develop category specific impairments, though there have been documented cases of it occurring. Typically, a more generalized semantic impairment results from dimmed semantic representations in the brain.
Frontal lobe epilepsy (FLE) is a neurological disorder that is characterized by brief, recurring seizures arising in the frontal lobes of the brain, that often occur during sleep. It is the second most common type of epilepsy after temporal lobe epilepsy (TLE), and is related to the temporal form in that both forms are characterized by partial (focal) seizures.
Memory disorders are the result of damage to neuroanatomical structures that hinders the storage, retention and recollection of memories. Memory disorders can be progressive, including Alzheimer's disease, or they can be immediate including disorders resulting from head injury.
The orbitofrontal cortex (OFC) is a prefrontal cortex region in the frontal lobes of the brain which is involved in the cognitive process of decision-making. In non-human primates it consists of the association cortex areas Brodmann area 11, 12 and 13; in humans it consists of Brodmann area 10, 11 and 47.
Akinetic mutism is a medical condition where patients tend neither to move (akinesia) nor speak (mutism). Akinetic mutism was first described in 1941 as a mental state where patients lack the ability to move or speak. However, their eyes may follow their observer or be diverted by sound. Patients lack most motor functions such as speech, facial expressions, and gestures, but demonstrate apparent alertness. They exhibit reduced activity and slowness, and can speak in whispered monosyllables. Patients often show visual fixation on their examiner, move their eyes in response to an auditory stimulus, or move after often repeated commands. Patients with akinetic mutism are not paralyzed, but lack the will to move. Many patients describe that as soon as they "will" or attempt a movement, a "counter-will" or "resistance" rises up to meet them.
Utilization behavior (UB) is a type of neurobehavioral phenomena that involves someone grabbing objects in view and starting the 'appropriate' behavior associated with it at an 'inappropriate' time. Patients exhibiting utilization behavior have difficulty resisting the impulse to operate or manipulate objects which are in their visual field and within reach. Characteristics of UB include unintentional, unconscious actions triggered by the immediate environment. The unpreventable excessive behavior has been linked to lesions in the frontal lobe. UB has also been referred to as "bilateral magnetic apraxia" and "hypermetamorphosis".
Anosodiaphoria is the inability to recognize the full importance of a neurological disability brought on by a brain lesion. It might be specifically associated with defective functioning of the frontal lobe of the right hemisphere.
In psychology and neuroscience, executive dysfunction, or executive function deficit, is a disruption to the efficacy of the executive functions, which is a group of cognitive processes that regulate, control, and manage other cognitive processes. Executive dysfunction can refer to both neurocognitive deficits and behavioural symptoms. It is implicated in numerous psychopathologies and mental disorders, as well as short-term and long-term changes in non-clinical executive control. Executive dysfunction is the mechanism underlying ADHD paralysis, and in a broader context, it can encompass other cognitive difficulties like planning, organizing, initiating tasks and regulating emotions. It is a core characteristic of ADHD and can elucidate numerous other recognized symptoms.
The applause sign is a behavioural indicator, relevant to neurodegenerative conditions, characterised by a patient’s inability to execute the same number of hand claps as demonstrated by an examiner.
The mini-SEA is a neuropsychological battery aiming to evaluate the impairment of the social and emotional cognition. Developed by Maxime Bertoux in 2012, the mini-SEA has been preferentially designed for the assessment, follow-up and diagnosis of neurodegenerative diseases such as the frontotemporal dementia, but is more generally designed to evaluate the integrity of the frontal lobes.
Hyperreligiosity is a psychiatric disturbance in which a person experiences intense religious beliefs or episodes that interfere with normal functioning. Hyperreligiosity generally includes abnormal beliefs and a focus on religious content or even atheistic content, which interferes with work and social functioning. Hyperreligiosity may occur in a variety of disorders including epilepsy, psychotic disorders and frontotemporal lobar degeneration. Hyperreligiosity is a symptom of Geschwind syndrome, which is associated with temporal lobe epilepsy.
Organic personality disorder (OPD) or secondary personality change, is a condition described in the ICD-10 and ICD-11 respectively. It is characterized by a significant personality change featuring abnormal behavior due to an underlying traumatic brain injury or another pathophysiological medical condition affecting the brain. Abnormal behavior can include but is not limited to apathy, paranoia and disinhibition.
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