Navigating the Terrain of Frontal Lobe Syndrome - Cognition Unleashed

Introduction

Frontal lobe syndrome is a clinical syndrome that results from impaired functioning or damage to the prefrontal cortex. The areas involved include the anterior cingulate, lateral prefrontal cortex, orbitofrontal cortex, and frontal poles. It is a broad term used to describe the damage to higher functioning processes of the brain. This includes language and speech, motivation, planning, and social behavior.

Where Is the Frontal Lobe Present, and What Functions Does It Perform?

The frontal lobe of the brain extends from the front of the brain to almost midway and is considered the largest part of the brain.

The brain is made up of two halves or hemispheres.

1. The right hemisphere.

2. The left hemisphere.

These hemispheres are divided into three parts:

• Forebrain.

• Midbrain.

• Hindbrain.

The forebrain includes the cerebrum. The outer layer of the cerebrum is called the cerebral cortex, which is divided into four lobes:

• Frontal lobe.

• Parietal lobe.

• Temporal lobe.

• Occipital lobe.

Each lobe has specific functions, and damage to any one of them will cause impaired functions related to that lobe. The following conditions can damage the frontal lobe, such as trauma, stroke, and dementia.

Damage to the frontal lobe can lead to a variety of symptoms, such as:

• Behavioral problems.

• Language or speech-related problems.

• Loss of muscle strength.

• Depression.

What Are the Functions of the Frontal Lobe?

The main functions of the frontal lobe are as follows:

• Social and Emotional Skills: The frontal lobe plays an important role in self-control and decision-making. It regulates emotions and manages interaction with others. It regulates how one behaves and helps us determine what is socially acceptable and what is not.

• Motor Functions: The motor strip region of the frontal lobe controls and directs body movements. The left side of the region controls the right side of the body and vice versa.

• Language, Reasoning, Imagining, and Thinking: The frontal lobe is complex and helps in performing complex tasks, innovation, and imagination. It controls higher-order thinking and problem-solving. It helps in concentration.

The frontal lobe has a dominant side and a non-dominant side. It is generally on the left but can be on the right side.

The dominant side performs the following functions such as:

• Language and speech.

• Logical thinking.

• Analytical reasoning.

The non-dominant side is involved in creative functions such as:

• Imagination.

• Creativity.

• Curiosity.

• Musical and artistic ability.

• Intuition.

What Are the Causative Factors of Frontal Lobe Syndrome?

The etiological factors related to frontal lobe disorder include:

• Closed head trauma.

• Cerebrovascular disease.

• Tumors.

• Neurodegenerative disease.

• Epilepsy with lobe foci.

• Multiple sclerosis.

• Human immunodeficiency virus (HIV).

• Early onset dementia.

Pathophysiology:

Based on the studies with frontal lobe syndrome, emphasis on lesions involving dorsolateral convexity and ventromedial orbitofrontal cortex has been given. Both lesions affect behavior in different ways.

• Ventromedial Orbitofrontal Cortex: It causes frontal lobe personality. The lesion in this area causes dramatic changes in behavior, resulting in impulsivity and lack of judgment.

• Anterior Cingulate and Dorsolateral Syndrome: Lesions in these areas cause deficits in learning, memory, planning, attention, and motivation. Dorsolateral lesions may lead to apathetic and abulic states.

• New research within the dorsolateral frontal cortices revolves around intuition. The frontal lobe can communicate with the limbic system and association cortex.

Histopathology:

Frontal lobe syndrome caused by neurodegenerative disorders is usually due to two main histopathologies such as:

• Alpha-synuclein.

• Tau protein.

Alpha-synuclein is associated with Parkinson's disease, multiple system atrophy, and diffuse Lewy body dementia.

Whereas tauopathies involve frontotemporal dementia, supranuclear palsy, chronic traumatic encephalopathy, and advanced Alzheimer's disease.

How to Evaluate Frontal Lobe Syndrome?

• Before diagnosing frontal lobe syndrome, it is of utmost importance to rule out other causes that may cause cognitive impairment, such as vitamin B12, syphilis serology, and thyroid function.

• Computed tomography (CT) scan should be done to diagnose acute bleeding or hydrocephalus.

• Magnetic resonance imaging (MRI) should be done to rule out hematomas, atrophy, or any other pathologies.

• If there are clinical signs and symptoms indicating frontotemporal dementia, a deoxy glucose positron emission tomography (PET) scan is suggested.

How to Diagnose Frontal Lobe Syndrome?

• The first and foremost thing done to test patients with frontal lobe syndrome is to perform a neurological examination. During the examination, behavioral changes should be noted, such as abulia, insight impairment, utilization behavior, environmental dependency, incontinence, etc.

• The patient’s history should be obtained from family and close relatives. Mental status should be examined to evaluate attention, memory, perseveration, ability to suppress inappropriate responses, etc.

• Other examinations include optokinetic nystagmus testing, hemiparesis, olfaction, motor persistence, gegenhalten, primitive reflexes, gait analysis, skull shape, etc. During the examination, also note whether the patient was subject to trauma, abuse, or psychiatric stress.

How to Treat Frontal Lobe Syndrome?

Treatment solely depends on the type of pathology present and the severity of the condition. Dementia, such as the lewy body, can be treated with acetylcholinesterase inhibitors. Whereas acetylcholinesterase inhibitors are not found beneficial in treating frontotemporal degeneration (FTD). The non-medical treatment used in treating FTD includes physical and occupational therapies.

Speech therapy is found beneficial in treating symptoms such as apraxia, aphasia, and dysarthria. For treating synuclein-associated psychoses, Pimavanserin, a selective serotonin 5-HT2A inverse agonist, is found useful.

Differential Diagnosis of Frontal Lobe Syndrome

Differential diagnoses include:

• Cerebrovascular accidents.

• Head trauma.

• Cerebral malignancies.

• Seizures related to the frontal lobe.

• Anoxic injury.

• Alzheimer’s disease.

• Hydrocephalus.

• Schizophrenia.

• Parkinson's disease.

• Huntington's disease, etc.

Prognosis of Frontal Lobe Syndrome

The prognosis usually depends on the underlying cause. For infections or resectable tumors (reversible and treatable cases), the prognosis is more favorable. For neurodegenerative disorders such as frontotemporal dementia, treatment is usually symptomatic, and the patient will eventually succumb to the disease.

What Complications Arise Due to Frontal Lobe Syndrome?

Complications are usually specific. Progressive neurodegenerative disorders have behavioral and social consequences requiring multiple support services both for the patient and their families.

Conclusion

Frontal lobe syndrome is a clinical disease caused by injury and reduced function of the prefrontal cortex, a vast association area of the frontal lobe. The etiological factors related to frontal lobe disorder include head trauma, cerebrovascular disease, head tumors, neurodegenerative disease, epilepsy, multiple sclerosis, and early-onset dementia. Frontal lobe syndrome caused by neurodegenerative disorders is usually due to two main histopathologies such as alpha-synuclein and tau protein. Diagnosis is usually made through a series of neurological examinations, and treatment solely depends on the type of pathology present and the severity of the condition.