What Are the Differences Between the Frontal Lobe and Temporal Lobe?
In 1892, Czech psychiatrist Arnold Pick first reported a 71-year-old male patient with clinically severe speech impairment accompanied by obvious mental symptoms. An autopsy revealed severe atrophy of the left cerebral temporal cortex. He then reported four patients with atrophy of the temporal lobe or frontotemporal lobe, whose main manifestations were speech changes and mental behavior abnormalities. Pathological examination revealed diffuse balloon-shaped neurons (Pick cells) and intracytoplasmic silver-like inclusion bodies (Pick bodies). In 1926, Onari and Spatz referred to this disease, which is dominated by frontotemporal atrophy, as "Pick's disease." In the 1980s and 1990s, some scholars found that the clinical characteristics of certain degenerative diseases are similar to those of Pick's disease, but lack typical pathological manifestations (Pick cells and Pick bodies). Many terms have emerged, such as frontotemporal dementia, non-Alzheimer's disease of frontal degeneration, frontotemporal degeneration, primary progressive aphasia, and semantic dementia. In recent years, based on the more consistent pathological characteristics of prefrontal and pretemporal atrophy, this type of disease is collectively referred to as frontotemporal lobe degeneration (FTLD). Then, according to the site of atrophy and the corresponding early prominent symptoms, the clinical is further divided into three subtypes: frontotemporal dementia, progressive non-fluent aphasia, and semantic dementia (see Classification of diseases). [1]
| Zhou Aihong | (Deputy Chief Physician) | Department of Neurology, Xuanwu Hospital |
Frontotemporal lobe degeneration (FTLD) is a degenerative disease of the central nervous system, characterized by degenerative atrophy of the frontal and temporal lobe of the brain. . Patients often have onset in the pre-senile period, with personality changes, social behavior abnormalities, and language expression or naming disorders as the earliest and most prominent symptoms. The memory and visual spatial function are less damaged, but as the disease progresses (3-4 years later) The patient eventually developed comprehensive dementia and functional decline. In the early stages of the disease, limb movement is usually normal, but some patients may be associated with Parkinson's syndrome or motor neuron disease. Its etiology and pathogenesis are not clear, and may be related to tau gene mutations.
- Western Medicine Name
- Frontotemporal degeneration
- English name
- frontotemporal lobe degeneration, FTLD
- Affiliated Department
- Internal Medicine-Neurology
- Disease site
- brain
- The main symptoms
- Personality changes, abnormal social behavior, language expression or naming disorders
- Main cause
- Unknown cause
- Multiple groups
- Older age (45-65 years)
Introduction of frontotemporal degeneration disease
In 1892, Czech psychiatrist Arnold Pick first reported a 71-year-old male patient with clinically severe speech impairment accompanied by obvious mental symptoms. An autopsy revealed severe atrophy of the left cerebral temporal cortex. He then reported four patients with atrophy of the temporal lobe or frontotemporal lobe, whose main manifestations were speech changes and mental behavior abnormalities. Pathological examination revealed diffuse balloon-shaped neurons (Pick cells) and intracytoplasmic silver-like inclusion bodies (Pick bodies). In 1926, Onari and Spatz referred to this disease, which is dominated by frontotemporal atrophy, as "Pick's disease." In the 1980s and 1990s, some scholars found that the clinical characteristics of certain degenerative diseases are similar to those of Pick's disease, but lack typical pathological manifestations (Pick cells and Pick bodies). Many terms have emerged, such as frontotemporal dementia, non-Alzheimer's disease of frontal degeneration, frontotemporal degeneration, primary progressive aphasia, and semantic dementia. In recent years, based on the more consistent pathological characteristics of prefrontal and pretemporal atrophy, this type of disease is collectively referred to as frontotemporal lobe degeneration (FTLD). Then, according to the site of atrophy and the corresponding early prominent symptoms, the clinic is further divided into three subtypes: frontotemporal dementia, progressive nonfluent aphasia, and semantic dementia (see Classification of diseases). [1]
Frontotemporal Degeneration Pathophysiology
With the development of immunohistochemistry and biochemistry, the pathology of frontotemporal degeneration has been deeply understood.
(1) Gross pathology: The main manifestation is localized brain atrophy, and the weight of the patient's whole brain is reduced, most of which are between 1000 and 1250 g. The atrophy is mainly located in the cerebral hemisphere, including most of the frontal, temporal, and insular lobe regions, and the anterior parietal lobe, sometimes forming a "knife-like" atrophy. The initial lesions are not exactly the same, but as the disease progresses, the lesions often extend to other sites. Some patients may involve subcortical structures such as the basal ganglia and substantia nigra.
(2) Microscopic pathology: Hematoxylin-eosin staining (HE staining) showed microvesicle degeneration and neuron loss in affected cortex, and balloon-like neurons were seen in some patients. Changes in white matter demyelination and glial cell proliferation can also be seen. Some patients may have severe neuronal loss in the basal ganglia and substantia nigra.
(3) Immunohistochemistry: Tau and ubiquitin staining were positive in some cases of immunohistochemical staining, suggesting the deposition of tau protein and ubiquitin.
Causes of frontotemporal degeneration
The etiology and pathogenesis are not completely clear. About 10% to 30% of patients are associated with mutations in the tau gene located on chromosome 17. Tau protein is an important microtubule-related protein, which promotes the assembly of microtubules and participates in the maintenance of cell morphology, material transport, cell division and other important biological processes. The tau gene mutation can reduce the binding of tau protein to microtubules, disintegrate the microtubules, and cause neuronal damage. At the same time, the abnormally deposited tau protein causes neuronal toxicity, leading to cell degeneration. In addition, some familial frontotemporal degeneration may be associated with mutations in the progranulin (PGRN) gene. Progranulin is a growth factor. Gene mutations may cause a reduction in growth factors and prevent nerve growth and repair. Recently, abnormal phosphorylation of TAR-DNA binding protein 43 (TDP-43, a nuclear protein that regulates transcription) has been found to be closely related to frontotemporal degeneration with motor neuron disease. Some rare genes or gene locus mutations have been reported. [2]
Frontotemporal degeneration disease classification
The disease spectrum of frontotemporal degeneration includes a series of clinically and pathologically different phenotypes. According to the site of atrophy and the corresponding early prominent symptoms, the clinic can be further divided into three subtypes: frontotemporal dementia, progressive non-fluent aphasia, and semantic dementia. Frontotemporal dementia is characterized by atrophy of the frontal and anterior temporal lobes, and clinical and behavioral and personality changes are prominent features throughout the disease; progressive non-fluent aphasia is the dominant side of the brain (most people are on the left) or double Caused by atrophy of lateral lateral fissure cortex, which is characterized by severe impairment of language expression; semantic dementia is associated with atrophy of the dominant temporal temporal cortex of the brain and is characterized by naming disorders and loss of vocabulary comprehension. Sometimes, spinal anterior horn cells are also affected in patients with frontotemporal degeneration. Therefore, some patients may have motor neuron disease at the same time, which is called the frontotemporal degeneration-motor neuron disease variant. Some patients may also have Parkinson's syndrome. [3]
Clinical manifestations of frontotemporal degeneration
Frontotemporal degeneration is relatively common in pre-senescence, accounting for 8% to 17% of early-onset dementias at necropsy, ranking third among all degenerative dementias, behind Alzheimer's disease and Lewy body dementia. The prevalence of the 45-64 age group is 4-15 / 100,000. About 40% have a positive family history. Frontal-temporal degeneration is characterized by progressively worsening language disorders and mental and behavioral abnormalities, which seriously affects the patient's normal communication and daily activities. With the progress of the disease, the patient develops to complete aphasia and comprehensive dementia, and completely depends on the family members to see passport data. Because the disease often occurs in pre-elderly age, and other functions of the patient's body are still in a good stage, compared with dementia that occurs in advanced age (such as Alzheimer's disease), frontotemporal degeneration has a greater impact on the quality of life of the patient and his family. serious.
Clinically, the age of onset of frontotemporal degeneration is most common between the ages of 45 and 65, but it can be as early as 17 years old and as late as over 80 years old. There is no clear gender difference. Its common symptoms are insidious onset, continuous progress, prominent manifestations of mental and behavioral abnormalities, and language dysfunction. Other cognitive impairments are relatively mild in the early stages. But as the disease progresses, other symptoms will eventually appear. Frontotemporal degeneration and cortical basal ganglia degeneration, progressive supranuclear palsy, motor neuron disease, and Parkinson's disease sometimes overlap with each other in pathology, genetics, and clinical aspects, and some patients with frontotemporal degeneration may have clinical symptoms of the above diseases. which performed. Some patients may experience autonomic symptoms such as low blood pressure, low body temperature, and instability. The symptoms of each subtype are as follows:
1. Frontotemporal dementia: Also known as frontal variant of frontotemporal lobe degeneration (fv-FTLD), which accounts for 40% of frontotemporal degeneration. Personality changes, abnormal social behavior, and impaired executive function are the earliest and most prominent symptoms, and they run through the disease. The patient's personality changed significantly, regardless of social rules and moral constraints. Some patients are impulsive, overactive, and indulgent. Some patients show indifference, lack of will, reduced activity, and stubborn personality. Some patients experience persistent and stereotyped behaviors, hyperalgesia, and dietary changes. Impaired planning, self-control, generalization, judgment, attention, problem solving, etc. Impairment of memory, perception, and visual spatial abilities is relatively late. Early frontal lobe primitive reflexes can occur, late periods can appear rigidity, tremor, and motor neuron disease.
2. Progressive nonfluent aphasia : Progressive nonfluent aphasia (PNFA) accounts for 20% of frontotemporal degeneration. The main clinical features are progressive aggravation of non-fluent aphasia. Patients have reduced spontaneous language, difficulty in finding words, short speech, lack of grammatical structure, phonetic errors, naming disorders, and can be accompanied by reading and writing disorders (alexia and dyslexia). Early understanding of the meaning of words was relatively reserved. Before the comprehensive decline of intelligence, language function impairment lasted for at least 2 years or more, and cognitive and work skills other than language function were basically retained. Patients with advanced disease are silent, unable to communicate with people, and have behavioral abnormalities similar to frontotemporal dementia. Physical examination showed primitive reflexes, part of extrapyramidal symptoms or motor neuron disease.
3. Semantic dementia: also known as temporal variant of frontotemporal degeneration, tv frontotemporal degeneration, accounting for 40% of frontotemporal degeneration. It is characterized by progressively worsening semantic memory and comprehension barriers. Patients' memory loss of semantic knowledge such as words, objects, and characters is manifested as severe naming and comprehension barriers, such as the inability to name objects such as buttons and toothbrushes. And loses memory of its function. The patient's spontaneous language is fluent, but his speech is empty and lacks solid words. "East" is often used to refer to specific objects, and "do" is used to refer to specific behaviors, which can be accompanied by reading and writing. May have behavioral changes, often showing compulsive and rigid behavior. Before the comprehensive decline of intelligence, language function impairment lasted for at least 2 years or more. As the disease progressed, other cognitive dysfunctions appeared. Later in the course of the disease, primitive reflexes, inability to move, rigidity, and tremor appeared. [1] [2]
Frontotemporal degeneration complications
Complications often occur in the late stages of the disease. In the later stage of the disease, complications such as falls, fractures, malnutrition, aspiration pneumonia, and urinary tract infections may occur due to dyskinesias, eating disorders, and defecation disorders.
Diagnosis of frontotemporal degeneration
Frontal-temporal degeneration
Routine blood, urine, and cerebrospinal fluid tests are normal, and neuropsychological assessment (assessment of intelligence and behavior) and brain imaging tests have important auxiliary roles in diagnosis and differential diagnosis.
1. Neuropsychological assessment: Neuropsychological assessment can help with diagnosis and differential diagnosis.
(1) Frontotemporal dementia: manifested as significant frontal lobe damage, mainly involving executive function, behavior, and personality, without severe forgetfulness, aphasia, or spatial dysfunction. Tests that evaluate executive function and personality behavior are sensitive to it. Patients performed poorly on the Wisconsin Card Sorting Test, the Tower of London Test, the Wiring Test, and the Stroop Interference Test. The frontal behavioral inventory (FBI) is helpful for the early diagnosis and differential diagnosis of frontotemporal dementia, and the accuracy rate for identifying frontotemporal dementia and other types of dementia is 92.7%.
(2) Primary progressive aphasia: Language function assessment is more sensitive. Common tests include the Boston Naming Test, Chinese Aphasia Set Test, and Semantic or Speech Fluency Test. Patients presented with non-fluent aphasia, reduced spontaneous language, less grammatical structure, and naming problems. Some types of words spoken within one minute were reduced, and some were accompanied by reading and writing problems. The memory, perception, and spatial structure ability tests were relatively good.
(3) Semantic dementia: commonly used semantic ability-related tests for evaluation, including object naming, picture naming, description-naming, word-painting matching, word definition tasks (such as presenting "ducks", asking subjects to give "living in water" Relevant descriptions of "li, flat mouth", etc.), classification tasks (such as presenting "lion and mouse, ask if they belong to the same category), semantic category fluency tests, etc., patients are significantly worse than normal people. Episodic memory, perception, spatial structure The ability check is relatively good, but semantic disorders often affect other cognitive tests, such as asking the patient what season it is now, and the patient cannot answer because he does not understand the meaning of the season.
2. Brain imaging: CT or nuclear magnetic resonance (MRI) examinations show limited frontal and / or anterior temporal lobe atrophy in patients with frontotemporal dementia, and the lesions can be symmetrical or asymmetrical. In patients with primary progressive aphasia, local atrophy around the lateral fissure can be seen, and the advantage is focused on the non-dominant side. Semantic dementia shows anterior temporal lobe atrophy, with a focus on the non-dominant side. PET or SPECT showed reduced metabolism at the corresponding site, which appeared earlier than MRI.
Diagnosis of frontotemporal degeneration
According to the onset of premature onset in the elderly, the early manifestations of mental and behavioral abnormalities and language dysfunction are prominent. Other cognitive impairments are relatively minor, and the disease continues to progress. Combined with imaging, the above symptoms caused by other diseases can be diagnosed. The following table is a summary of the clinical diagnostic criteria recommended by the International Frontotemporal Degeneration Working Group published in 2001.
Table 1 Diagnostic criteria of frontotemporal degeneration (2001) |
|---|
1. Behavioral or cognitive impairments manifested as one of the following: |
(1) Sustained personality changes occur early in the disease and are characterized by behavioral adjustment disorders that often lead to inappropriate behavioral responses or behavioral activities; |
(2) Progressive language dysfunction occurs early in the disease, which is characterized by language expression disorders or severe naming disorders and semantic disorders. |
2. The and deficiencies described above have resulted in significant impairments in social or occupational functions and have been significantly less significant than before. |
3. The course of disease is characterized by gradual onset and slow progress. |
4. The above manifestations are not caused by other central nervous system diseases (such as cerebrovascular disease) or systemic diseases (such as hypothyroidism) or drug abuse. |
5. The above manifestations do not only occur in delirium and non-mental diseases (such as depression) can be explained. |
Differential diagnosis of frontotemporal degeneration
It should be distinguished from other diseases with obvious mental behavior or language disorders. The main points of identification are the sequence of behavioral symptoms, language disorders and other cognitive impairments, as well as auxiliary examinations such as neuropsychological assessment and imaging.
1. Alzheimer's disease: Alzheimer's disease is the most common type of dementia in old age. Frontotemporal degeneration and Alzheimer's disease are both degenerative diseases, with insidious onset and continuous progress. Mental behavioral symptoms and language and semantic disorders will occur at some stage of the disease. They should be identified.
Table 2 Key points for identifying frontotemporal degeneration and Alzheimer's disease |
|---|
| Frontotemporal degeneration | Alzheimer's disease |
Age of onset | More common in pre-senescence | More common in old age |
Personality changes or language barriers | Appears early, severe | Middle-late stage disease |
Executive function | Appears early, severe | Middle-late stage disease |
Episodic memory disorder | Appear late | Appears early, severe |
Disorientation | Early no | Early common |
Visual spatial dysfunction | Early no | Early common |
Daily activity | In addition to frontotemporal dementia, early retention | Damage early |
Film degree exam | Early frontal or anterior temporal lobe damage | Early atrophy of hippocampus and medial temporal lobe |
Nervous system signs | Some patients may have symptoms of extrapyramidal or motor neuron disease at an early stage | No early, abnormal gait, increased tension, etc. |
2. Lewy body dementia: Lewy body dementia often has cognitive impairment, Parkinson's symptoms, and mental and behavioral abnormalities. It needs to be distinguished from frontotemporal dementia in frontotemporal degeneration. However, the cognitive impairment of Lewy body dementia is volatility, and the patient's orientation, visual spatial ability, and computing ability are affected, and these capabilities are relatively impaired in patients with frontotemporal degeneration. In addition, unlike frontotemporal degeneration, brain atrophy in patients with Lewy body dementia is more diffuse and can be identified.
3 Schizophrenia: Emotional, personality, behavioral, and cognitive changes in schizophrenia should be distinguished from frontotemporal dementia in frontotemporal degeneration. However, patients with schizophrenia often have stress-induced events, patients have obvious hallucinations, systemic and persistent delusions, and their cognitive impairment is relatively stable. CT and MRI have no characteristic brain changes and can be identified.
4 Simple aphasia caused by other reasons: Isolated language and semantic disorders in patients with primary progressive aphasia and semantic dementia can last for several years. It should be related to simple aphasia or semantic disorders caused by other causes such as cerebrovascular disease, herpes simplex virus encephalitis, etc. Identification. However, cerebrovascular disease and herpes simplex encephalitis are mostly acute, accompanied by focal signs of the nervous system, aphasia or semantic disorder improves after the acute phase, non-progressive, focal lesions on imaging can be identified. [3]
Frontotemporal degeneration disease treatment
There is no effective treatment method, mainly symptomatic, support, and exercise, which can stabilize the disease and control the symptoms to a certain extent. Treatment includes: 1. improving cognitive and communication skills; 2. controlling psycho-behavioral symptoms; 3. treating complications.
Frontotemporal degeneration improves cognitive and communication skills
(1) Drug treatment: The main drugs currently used in clinical treatment of dementia are cholinesterase inhibitors (such as donepezil, cabalatin, stone mountainine, etc.) and excitatory amino acid receptor antagonists (memantine hydrochloride). Excitatory amino acid receptor antagonists are well tolerated, the patient's communication ability can be slightly improved, and at the same time, psycho-behavioral symptoms have improved. Because patients with frontotemporal degeneration have no abnormalities in the cholinergic system, cholinesterase inhibitors are usually ineffective, but for some patients who may be associated with Alzheimer's disease (Decreased space capacity) has a certain effect.
(2) Non-pharmacological treatment : In terms of non-pharmacological intervention, there have been literature reports on the results of semantic training of 2 patients with semantic dementia and 3 patients with semantic memory impairment caused by herpes simplex virus encephalitis, and found that patients can relearn the names of people And faces, you can effectively remember the names of newly met friends and the names of drugs prescribed to them, and you can relearn some forgotten words. This effect continues after the training stops. This evidence suggests that semantic training may enable patients to regain semantic knowledge. Therefore, patients should be trained as much as possible in terms of language expression and semantic memory. Because patients often have reading and writing difficulties, they should also exercise in writing and reading.
Frontotemporal degeneration controls psychobehavioral symptoms
(1) Non-drug treatment: Non-drug treatment mainly includes psychological intervention for patients and caregivers. It is the first choice for improving mental behavior. Caregivers should respect the patient and be friendly to the language, while keeping the environment safe and relatively quiet to avoid inducing the psycho-behavioral symptoms of the patient. In addition, the behavior and emotional changes of patients need to be analyzed to find the causes or events that are prone to trigger in order to prevent and avoid inducements.
(2) Drug treatment: If the psycho-behavioral symptoms are mild, drug treatment is not necessary. For use, excitatory amino acid receptor antagonists are preferred. If symptoms persist, selective 5-HT reuptake inhibitors can be used. These drugs can reduce de-inhibition, impulsivity, repetitive stereotypes, and eating disorders. When the above drugs are not effective for mental symptoms, atypical antipsychotic drugs such as olanzapine or quetiapine can be used with caution, but the following principles must be followed: Start at a low dose, generally from 1/4 to 1/2 tablets per day Slow increase, if the effect is not obvious, in the case of no obvious side effects, increase 1/4 tablets every 1 to 2 weeks; try to use the minimum effective dose, generally not more than 1 tablet per day; closely monitor the medication situation and Side effects; fully explain the risks of treatment to patients and their families before use.
Treatment of frontotemporal degeneration complications
Late fall should prevent falls when gait abnormalities occur. Avoid cough and aspiration pneumonia, and avoid urinary tract infections, and should be actively treated if they occur. Selective 5-HT reuptake inhibitors have a certain effect in people with eating disorders. Nasal feeding is required for lower stomach tube if necessary. [2]
Prognosis of frontotemporal degeneration
This type of disease has a continuous and progressive course with a poor prognosis. The course of disease is 5 to 12 years, and it is mostly due to complications such as lung and urinary infections and bedsores.
Frontotemporal degeneration diet and precautions
Eat healthy. Some patients have increased food intake and do not know how to control them. They need family control. Some patients (especially advanced patients) eat less, need to eat less and eat more, and increase nutrition.
Prevention of frontotemporal degeneration
The current prevention of dementia is to avoid or control risk factors and strengthen protective factors. Risk factors for dementia can be divided into 4 categories:
(1) Demographic factors: age, education level;
(2) Genetic factors;
(3) vascular factors: hypertension, diabetes, heart disease, hyperlipidemia, etc .;
(4) Life habits: anxiety / depression, autism, etc. Protective factors include: regular physical exercise, regular mental exercise, skilled hobbies, and participation in social activities. It is recommended to control interventional risk factors (such as vascular factors, lifestyle habits) and adhere to protective behaviors.
Frontotemporal degeneration expert opinion
At present, the disease is easy to be missed or misdiagnosed. Patients with mental and behavioral abnormalities with (or without) language disorders after the age of 40 should go to the neurology department to determine whether it is a mental illness caused by an organic brain disease (such as this disease) Behavioral symptoms. Although there is no effective treatment for the disease at present, it can stabilize the disease to a certain extent, control symptoms, and reduce the burden on caregivers. [1] [2] [3]
