Index
Known as DFT (for its acronym in English) is the clinical presentation of frontotemporal lobar degeneration.
It is characterized by a progressive neuronal loss that predominantly affects the frontal or temporal lobes and the typical loss of more than 70% of the spindle neurons, while other types of neurons remain intact.
It was first described by Arnold Pick in 1892 and was originally called ” Pick’s disease“, a term now reserved for Pick’s disease, a specific type of frontotemporal dementia.
After the prevalence of Alzheimer’s disease (AD), frontotemporal dementia represents 20% of the cases of recent onset dementia. The signs and symptoms usually manifest at the end of adulthood, most commonly between the ages of 45 and 65, affecting approximately equal men and women.
Common signs and symptoms include significant changes in social and personal behavior, apathy, dullness of emotions and deficits in expressive and receptive language. Currently, there is no cure for frontotemporal dementia, but there are treatments that help relieve symptoms.
Signs and symptoms of frontotemporal dementia
Frontotemporal dementia is traditionally difficult to diagnose due to the heterogeneity of the associated symptoms. The signs and symptoms are classified into groups according to the functions of the frontal and temporal lobes:
Frontotemporal dementia behavior variant
It is characterized by changes in behavior and social behavior, with loss of social awareness and poor control of impulses.
Frontotemporal variant dementia of behavior is the form of frontotemporal dementia behavioral variant (FVC) characterized by early and progressive changes in personality, emotional dullness and / or loss of empathy.
Patients experience difficulties modulating behavior, and this often results in socially inappropriate responses or activities. Language impairment can also occur after changes in behavior have become noticeable.
Patients usually begin to have symptoms sometime in their 50s, although it may occur as early as age 20 or as late as age 80.
As with all frontotemporal degeneration, the course of frontotemporal variant behavior dementia will vary from one person to another.
Not all symptoms will be experienced by each person, nor will these symptoms develop in a pre-established sequence.
Key clinical features of frontotemporal variant behavior dementia
The hallmark of frontotemporal variant behavior degeneration is a progressive deterioration in a person’s ability to control or adjust their behavior in different social contexts resulting in embarrassing and inappropriate social situations that may be one of the most disturbing facets of frontotemporal degeneration .
People manifest a loss of empathy early in the disorder that is often considered as indifference to others, including loved ones. Apathy or lack of motivation may also be present.
In general, the patient does not recognize the changes in their own behaviors, nor shows awareness or concern about the effect that these behaviors have on the people around them.
Behavioral symptoms
Hyperoral behaviors include overeating, dietary compulsions, in which the person is limited to eating only specific foods (such as a certain Lifesaver flavor, or eating food only from a fast food restaurant) or trying to consume inedible items.
Patients can consume excessive amounts of fluids, alcohol and cigarettes.
Stereotyped and / or repetitive behaviors can include rereading the same book several times, rubbing hands and clapping, humming a song repeatedly or walking to the same location day after day.
Personal hygiene habits deteriorate at the beginning of the progression of the disease, since the person does not perform the daily tasks of bathing, grooming and dressing properly.
Hyperactive behavior is exhibited by some patients, and may include agitation, rhythm, wandering, outbursts of frustration and aggression.
The Hypersexual behavior can range from a preoccupation with sexual jokes to compulsive masturbation.
Impulsive acts can include theft, impulse buying and taking food from another person’s plate.
Emotional symptoms of frontotemporal dementia behavior variant
Apathy or indifference towards events and the surrounding environment can be characterized by less initiative and lack of motivation.
The lack of knowledge of the person’s own behavior develops early. In general, the patient does not recognize the changes in their own behaviors, nor shows awareness or concern about the effect that these behaviors have on the people around them, including loved ones.
Emotional dullness develops early in the course of the disorder and manifests as a loss of emotional warmth, empathy and sympathy, and the development of what appears to be indifference toward other people, including loved ones.
Mood swings can be abrupt and frequent.
Neurological symptoms of frontotemporal dementia behavior variant
Symptoms similar to those seen in Parkinson’s disease. Among patients with frontotemporal dementia with a behavioral variant, the term “parkinsonism” is used to distinguish the fact that they do not have Parkinson’s disease, although they do show some of these symptoms.
Symptoms include: decreased facial expression, bradykinesia (slowness of movement), stiffness (resistance to movement imposed) and postural instability.
Key pathological features of frontotemporal dementia behavior variant
Patients with variant behavioral frontotemporal degeneration may have one of three abnormal collections of proteins in their brain cells, which can be seen at autopsy: TDP-43 protein, tau or fused in sarcoma (FUS).
Most of these protein accumulations are usually found in areas of the brain that have lost the most volume, the frontal and temporal lobes.
Treatment for frontotemporal dementia variant of behavior
As with all forms of frontotemporal degeneration, there is currently no cure for frontotemporal variant behavioral dementia, and in most cases its progression can not be reduced.
Although no drug has been found to be effective specifically in frontotemporal degeneration, many physicians observe medications and treatment approaches directed at behavioral disturbances as needed.
For example, some patients with frontotemporal dementia benefit from selective serotonin reuptake inhibitors (SSRIs), which are used in the treatment of obsessive-compulsive behaviors, such as hoarding or craving sweets.
Doctors may also recommend antioxidants, such as coenzyme Q10, which are known to slow the progression of damage to brain cells in general, but there is little evidence to support this in frontotemporal degeneration.
Semantic dementia (DS)
It is characterized by the loss of semantic comprehension, which results in an impaired understanding of words, although speech remains fluid and grammatically blameless.
Semantic dementia, also known as primary progressive aphasia of the semantic variant, is a progressive neurodegenerative disorder characterized by the loss of semantic memory in both verbal and non-verbal domain.
However, the most common presentation symptoms are in the verbal domain (with loss of the meaning of the word).
Semantic dementia is a clinically defined syndrome, but it is associated with a predominant atrophy of the temporal lobe (left greater than the right) and, therefore, is sometimes called frontotemporal lobar degeneration of temporal variant.
Semantic dementia is one of the variants of primary progressive aphasia, which is the result of neurodegenerative disorders such as frontotemporal lobar degeneration or Alzheimer’s disease.
It is important to note the distinctions between Alzheimer’s disease and semantic dementia with respect to the types of memory affected.
In general, Alzheimer’s disease is known as a disorder that mainly affects episodic memory, defined as memory related to specific personal events for each individual.
Semantic dementia generally affects semantic memory, which refers to long-term memory that deals with common knowledge and facts.
It was first described by Arnold Pick in 1904 and in modern times was characterized by Professor Elizabeth Warrington in 1975, but did not receive the name of semantic dementia until 1989.
Clinical and neuropsychological characteristics, and their association with temporal lobe atrophy were described by Professor John Hodges and colleagues in 1992.
Semantic deficits
The defining characteristic of semantic dementia is the decrease in performance in tasks that require semantic memory. This includes difficulty in naming images and objects, comprehension of a single word, categorization and knowing uses and characteristics of objects.
Patients with semantic dementia also have difficulties in spontaneous speech creation, using words like “this” or “things” where more specific and meaningful words can be used.
The syntax is saved and patients with semantic dementia have the ability to discern syntactic violations and understand sentences with minimal lexical demands.
Patients with semantic dementia have a worse knowledge and association of concrete words, but retain knowledge and understanding of abstract words.
Patients with semantic dementia may retain knowledge of numbers and music, but have more difficulty with concrete concepts with visual associations.
Alterations in phonemic structure processing and prosodic predictability have also been observed.
Physical changes due to semantic dementia
The structural and functional magnetic resonance images show a characteristic pattern of atrophy in the temporal lobes (predominantly in the left), with greater involvement than inferior superiority and greater anterior atrophy of the temporal lobe than the posterior one.
This distinguishes it from Alzheimer’s disease, meta-analysis of magnetic resonance imaging and fludeoxyglucose; positron emission tomography studies confirmed these findings by identifying alterations in the lower temporal poles and tonsils as critical points of the disease.
Regions of the brain that have been discussed in the context of conceptual knowledge, semantic information processing and social cognition.
Based on these imaging methods, semantic dementia can be dissociated regionally from the other subtypes of frontotemporal lobar degeneration, frontotemporal dementia, and non-fluid progressive aphasia.
Selective glucose hypometabolism has been observed in the anterior temporal lobe, as well as in the medial temporal lobe and limbic areas.
Damage to the white matter tracts connecting the anterior temporal cortex with the longitudinal, arcuate, and uncinate fascicles, which are regions of the language network, is also seen using diffusion tensor images.
The images also show the alteration of the integrity of the axonal connections from the anterior temporal cortex to the frontal and posterior associative areas.
Functional abnormalities have also been observed in the structures of the hippocampus, the ventromedial prefrontal cortex, and the cingulate cortex.
Diagnosis and performance of semantic dementia
Patients with semantic dementia usually have difficulty generating familiar words or recognizing familiar objects and faces.
Clinical signs include fluid aphasia, anomie, impaired understanding of the meaning of the word, and associative visual agnosia (inability to attach images or semantically related objects).
Patients with semantic dementia have a low performance on semantic knowledge tests. The published tests include both verbal and non-verbal tasks, for example, Concrete and Abstract Word Synonym of Warrington , and The Pyramids and Palm Trees task .
The tests also reveal deficits in the name of the image (for example, “dog” for an image of a hippopotamus) and less fluidity of the category.
The question “What is a stapler?” Has been used as a primary diagnostic technique to discern how patients with semantic dementia understand the meaning of the word.
The speech of patients with semantic dementia is marked by pauses to search for words, a reduced frequency of content words, semantic paraphasias, circumlocutions, greater proportions of verbs to names, greater number of adverbs and multiple repetitions.
Patients with semantic dementia sometimes show symptoms of superficial dyslexia, a relatively selective impairment when reading low frequency words with unusual or atypical spelling to sound correspondences.
It is currently unknown why semantic memory is affected and semantic knowledge deteriorates in patients with semantic dementia, although the cause may be due to damage to an amodal semantic system.
This theory is supported by atrophy of the anterior temporal lobe, which is believed to contain a component of the semantic system that integrates conceptual information.
Others hypothesize that the damage is predominantly in the ventral temporal cortex, since patients with semantic dementia remember numbers and music, but have trouble associating visual cues with concrete words.
Due to the variety of symptoms presented by patients with dementia, it becomes more difficult to assess the capacity of semantic memory, especially with respect to musical elements.
In order to bypass explicit verbal learning tests for dementia, semantic melodic matching is a useful technique for detecting the semantic memory of patients with semantic dementia.
In addition, it is important to maintain that these tests should be compared with non-muscle domain tests, since musical cognition is not usually measured in patients with semantic dementia (there is less data available).
Relationship in genetics of semantic dementia
The majority of patients with semantic dementia have positive inclusions to ubiquitin, positive for TDP-43, tau-negative, although other pathologies have been described less frequently, namely, tau-positive Pick disease and Alzheimer’s disease.
Of all frontotemporal dementia syndromes, semantic dementia is less likely to occur in families and is usually sporadic.
Memory in dementia: musical objects, musical concepts and semantic memory
Melodies are a key aspect of musical objects that are thought to form the contents of semantic memory for music. Melodies are defined as familiar melodies that are associated with musical or extra musical meaning.
Using familiar songs, such as Christmas carols, they were used to test whether patients with semantic dementia could recognize the tones and melodies of songs if patients were simply given the words of the song.
In the analysis of semantic memory using melodies as stimuli, the contents of semantic memory can include many other aspects besides the recognition of melody, such as general information about music (composer, genre, year of release).
The results have shown that musicians suffering from semantic dementia are able to identify and recognize certain melodic tones.
Exploring the tests of music and semantic memory, the results of a study focused on the understanding of emotion in music indicated that patients with Alzheimer’s disease retained the ability to discern emotions from a song while patients with degenerative non-Alzheimer’s disease .
As with semantic dementia, they show problems of understanding these emotions. In addition, several patients with dementia, all with varied musical experience and knowledge, demonstrated an understanding of the fundamental rules of Western music.
Essentially, it was discovered that superior knowledge of music, such as the rules of composition, can be more solid than the knowledge of specific music.
With respect to the neurobiological correlates for this study, it was determined, through lesion studies, that the bilateral fronto-temporoparietal areas (but especially the left side of the brain) are significant in the associative processing of the melodies.
Based on the data from the imaging studies that analyzed the location of the processing melodies, it can be inferred that the anatomical location of the processes agrees with the findings that some patients with semantic dementia have intact recognition of the melody.
In addition, the neurobiological basis for the identification of musical emotions involved the limbic and paralimbic structures in this process.
In general, the results of these studies suggest that the neurobiological basis of musical semantic memory is located bilaterally in the cerebral hemispheres, probably around the fronto-temporal areas of the brain.
Unfortunately, due to the lack of studies that study musical semantic memory, the conclusions can not be more specific.
Treatment and prevention for semantic dementia
Currently there is no known curative treatment for semantic dementia. The average duration of the disease is 8 to 10 years, and its progression can not be reduced.
The progression of semantic dementia can lead to behavioral and social difficulties, so that supportive care is essential to improve the quality of life in patients with semantic dementia as they become more incomprehensible.
The continuous practice in lexical learning has been shown to improve semantic memory in patients with semantic dementia. Semantic dementia has no known preventive measures.
Progressive non-fluid aphasia
It is characterized by progressive difficulties in the production of speech. Progressive non-fluid aphasia is one of the three clinical syndromes associated with frontotemporal lobar degeneration.
Progressive non-fluid aphasia has an insidious onset of language deficits over time in comparison to other stroke-based aphasias that occur acutely after trauma to the brain.
This disorder commonly has a primary effect on the left hemisphere, causing symptomatic visualization of expressive language deficits (production difficulties) and, at times, can affect receptive skills by understanding a grammatically complex language.
Clinical characteristics of progressive non-fluid aphasia
The main clinical characteristics are the progressive difficulties of signature language with speech production.
There may be problems in different parts of the speech production system, therefore, patients may present an articulatory decomposition, a phonemic break (difficulties with sounds) and other problems.
However, it is rare for patients to have only one of these problems and most people will present with more than one problem. The features include:
- Hesitant and strenuous speech.
- Apraxia of speech.
- Stuttering (including the return of a stuttering infant).
- Anomia.
- Phonemic paraphasia (sound errors in speech, for example, “cato” for “cat”).
- Agrammatism (using the wrong word or time order).
As the disease develops, the amount of speech decreases and many patients become mute.
Cognitive domains other than language are rarely affected from the beginning. However, as the disease progresses, other domains may be affected. Problems with writing, reading and understanding speech can occur.
Classification
There is some confusion in the terminology used by different neurologists.
Mesulam’s original description in 1982 of the problems of progressive language caused by the neurodegenerative disease he called progressive primary aphasia (PPA) included patients with progressive non-fluid deficiency (PNFA, for its acronym in English) and progressive aphasia logopeda (LPA, for its acronym in English).
Imaging tests for progressive non-fluid aphasia
The imaging studies have shown different results that probably represent the heterogeneity of the language problems that can occur in cases of progressive lack of fluency. However, classic atrophy of the left perisylvian areas is observed.
The exhaustive meta-analyzes on magnetic resonance imaging and studies of positron emission tomography with fluorodeoxyglucose identified alterations in the entire left frontotemporal network for phonological and syntactic processing as the most consistent finding.
Based on these imaging methods, progressive non-fluid aphasia can be dissociated regionally from the other subtypes of frontotemporal lobar degeneration, frontotemporal dementia, and semantic dementia.
There is no curative treatment for this condition. Support management is useful.
Skills that are preserved in frontotemporal dementia
However, the following skills are preserved in the person with frontotemporal dementia:
Perception, is the organization, identification and interpretation of sensory information to represent and understand the information presented or the environment.
Spatial skills, spatial visualization capacity or visual-spatial ability is the ability to mentally manipulate two-dimensional and three-dimensional figures. It is usually measured with simple cognitive tests and is predictive of user performance with some types of user interfaces.
Memory, is the faculty of the mind through which information is encoded, stored and recovered.
Apraxia, is an motor disorder caused by damage to the brain (specifically the posterior parietal cortex) in which the individual has difficulty with motor planning to perform tasks or movements when asked, provided that the request or command is understood and is ready to perform the task.
The nature of brain damage determines the severity, and the absence of sensory loss or paralysis helps explain the level of difficulty.
In later stages of frontotemporal dementia, clinical phenotypes may overlap. Patients with frontotemporal dementia tend to have problems with binge eating and compulsive behaviors.
These binge eating habits are often associated with abnormal eating behavior that includes overeating, stuffing with food, changes in food preferences (cravings for more sweets, carbohydrates), eating inedible objects, and snatching others away.
Recent findings from structural magnetic resonance imaging research have indicated that dietary changes in frontotemporal dementia are associated with atrophy (wasting) in the right ventral insula, striatum, and orbitofrontal cortex.
Patients with frontotemporal dementia show marked deficiencies in executive functioning and working memory. Most patients with frontotemporal dementia become unable to perform skills that require complex planning or sequencing.
In addition to the characteristic cognitive dysfunction, several primitive reflexes known as frontal release signs can often be caused.
In general, the first of these signs of frontal release that appears is the palmomental reflex that appears relatively early in the course of the disease, while the palmar reflex and the rooting reflex appear late in the course of the disease.
In rare cases, frontotemporal dementia can occur in patients with motor neuron disease (typically amyotrophic lateral sclerosis). The prognosis for people with motor neuron disease is worse when combined with frontotemporal dementia, shortening survival by about one year.
Causes
A greater proportion of cases of frontotemporal dementia seems to have a family component than the most common neurodegenerative diseases, such as Alzheimer’s disease.
Each time more and more mutations and genetic variants are identified, so the lists of genetic influences require constant updating.
Tau-positive frontotemporal dementia with parkinsonism (FTDP-17) is caused by mutations in the MAPT gene (microtubule-associated tau protein) on chromosome 17 that encodes the Tau protein.
It has been determined that there is a direct relationship between the type of tau mutation and the neuropathology of genetic mutations.
Mutations in the splice junction of tau exon 10 lead to the selective deposition of repetitive tau in neurons and glia.
The disease phenotype associated with mutations in other parts of tau is less predictable, as described both typical neurofibrillary tangles (consisting of three repeat tau as 4 replicates) and Pick (consisting of three repeat tau).
The presence of tau deposits within the glia is also variable in families with mutations outside exon 10. This disease is now informally called FTDP-17T.
Frontotemporal dementia shows a link to the region of the tau locus on chromosome 17, but it is believed that there are two loci leading to frontotemporal dementia within megabases each other on chromosome 17.
Frontotemporal dementia caused by FTLD-TDP43 has numerous genetic causes. Some cases are due to mutations in the GRN gene, which is also found on chromosome 17.
Others are caused by valosin-containing protein mutations, although these patients present a complex picture of multisystem proteinopathy that may include amyotrophic lateral sclerosis, inclusion body myopathy, Paget’s disease of the bone, and frontotemporal dementia.
The most recent addition to the list is a repeat expansion of hexanucleotides in intron 1 of C9ORF72. Only one or two cases describing TARDBP mutations (the TDP-43 gene) were reported in a clinically pure frontotemporal dementia (frontotemporal dementia without motor neurone disease).
No genetic causes of the pathology of the FUS gene have been reported in frontotemporal dementia.
Pathology of frontotemporal dementia
There are 3 major histological subtypes found at autopsy: FTLD-tau, FTLD-TDP and FTLD-FUS. Dementia lacking distinctive histology (DLDH) is a rare and controversial entity.
New analyzes have allowed many cases previously described as dementia without distinctive histology to be reclassified in one of the positively defined subgroups. In rare cases, it was found that patients with clinical frontotemporal dementia had consistent changes with Alzheimer’s disease at autopsy.
The most severe cerebral atrophy seems to be associated with Pick’s disease, corticobasal degeneration and pathology of TDP protein associated with frontotemporal dementia behavior variant.
With respect to the genetic defects that have been found, repeated expansion in the C9orf72 gene is considered an important contribution to frontotemporal lobar degeneration, although defects in the GRN and MAPT genes are also associated with it.
Diagnosis
Structural magnetic resonance imaging often reveals atrophy of the frontal lobe or anterior temporal lobe, but in the first cases the exploration may seem normal. Atrophy can be bilateral or asymmetric.
The recording of images at different time points (for example, one year apart) may show evidence of atrophy that may otherwise be reported as normal (at individual time points).
Many research groups have begun to use techniques such as spectroscopy MRI, functional imaging and measurements of cortical thickness in an attempt to provide an earlier diagnosis the patient with frontotemporal dementia.
Positron emission tomography with fluorine-18-fluorodeoxyglucose classically shows anterior frontal and / or temporal hypometabolism, which helps to differentiate the disease from Alzheimer’s disease.
Positron emission tomography in Alzheimer’s disease classically shows biparietal hypometabolism. Meta-analyzes based on imaging methods have shown that frontotemporal dementia mainly affects a frontomedial network discussed in the context of social cognition or “theory of mind”.
This is in full agreement with the notion that on the basis of cognitive neuropsychological evidence, the ventromedial prefrontal cortex is an important locus of dysfunction at the beginning of the behavioral variant of frontotemporal degeneration.
The language subtypes of frontotemporal lobar degeneration (semantic dementia and non-fluid progressive aphasia) can be dissociated regionally by in vivo imaging approaches.
The confusion between Alzheimer’s disease and frontotemporal dementia is justifiable because of the similarities between their initial symptoms. Patients have no difficulty with movement and other motor tasks.
As the symptoms of frontotemporal dementia appear, it is difficult to differentiate between a diagnosis of Alzheimer’s disease and frontotemporal dementia.
There are clear differences in the behavioral and emotional symptoms of the two dementias, in particular, the dullness of the emotions seen in patients with frontotemporal dementia.
In the early stages of frontotemporal dementia, anxiety and depression are common, which can lead to an ambiguous diagnosis. However, over time, these ambiguities fade as this dementia progresses and symptoms of apathy, unique to frontotemporal dementia, begin to appear.
Recent studies over several years have developed new criteria for the diagnosis of frontotemporal variant behavioral dementia. Six different clinical features have been identified as symptoms of frontotemporal dementia of a behavioral variant.
- Disinhibition
- Apathy / inertia
- Loss of sympathy / empathy.
- Perseverative / compulsive behaviors.
- Hyperality
- Neuro-psychological profile dissecting.
Of the six characteristics, three must be present in a patient to diagnose one with possible frontotemporal dementia of a behavioral variant.
Similar to standard frontotemporal dementia, the main diagnosis comes from clinical trials that identify associated symptoms, rather than imaging studies.
The above criteria are used to distinguish frontotemporal variant dementia from the behavior of disorders such as Alzheimer’s and other causes of dementia.
In addition, the new criteria allow for a diagnostic hierarchy that distinguishes the possible frontotemporal dementia from the variant of possible, probable and definite behavior based on the number of symptoms present.
Neuropsychological tests
The progression of degeneration caused by the frontotemporal dementia behavioral variant can follow a predictable course. Degeneration begins in the orbitofrontal cortex and in medullary aspects such as the ventromedial cortex.
In later stages, it gradually expands its area to the dorsolateral cortex and temporal lobe. Therefore, the detection of dysfunction of the orbitofrontal cortex and the ventromedial cortex is important in the detection of early stage behavioral variant frontotemporal dementia.
As indicated above, a behavior change may occur before the appearance of any atrophy in the brain during the course of the disease.
Because of this, the exploration of images such as magnetic resonance imaging can be insensitive to early degeneration and it is difficult to detect frontotemporal dementia variant behavioral early stage.
In neuropsychology, there is a growing interest in the use of neuropsychological tests such as the Iowa game task or the Faux Pas recognition test as an alternative to images for the diagnosis of frontotemporal dementia of a behavioral variant.
It is known that both the Iowa game task and the Faux Pas test are sensitive to the dysfunction of the orbitofrontal cortex.
The Faux Pas recognition test is intended to measure one’s ability to detect types of false social errors (accidentally making a statement or action that offends others).
It is suggested that people with dysfunction of the orbitofrontal cortex show a tendency to commit social errors due to a lack of self-control.
Self-control is the ability of people to evaluate their behavior and ensure that their behavior is appropriate in particular situations.
The deterioration in self-control leads to the lack of signs of social emotion. Social emotions, such as shame, are important in the way they tell the individual that he or she should adapt social behavior appropriately to maintain relationships with others.
Although patients with damage to the orbitofrontal cortex retain intact knowledge of social norms, they do not apply it to real behavior because they do not generate social emotions that promote adaptive social behavior.
The other test, the Iowa gaming task, is a psychological test designed to simulate real-life decision-making. The underlying concept of this test is the somatic marker hypothesis.
This hypothesis argues that when people have to make complex and uncertain decisions, they use both cognitive and emotional processes to evaluate the values of the options available to them.
Each time a person makes a decision, both the physiological signals and the evoked emotion (somatic marker) are associated with their results and accumulate as experience.
People tend to choose the option that can produce the reinforced result with positive stimuli, therefore, it biases the decision making towards certain behaviors while avoiding others. It is believed that the somatic marker is processed in the orbitofrontal cortex.
The symptoms observed in frontotemporal dementia of behavioral variant are caused by the dysfunction of the orbitofrontal cortex, so these two neuropsychological tests could be useful to detect frontotemporal dementia variant behavior at the early stage.
However, since self-monitoring and somatic marker processes are so complex, they are likely to involve other regions of the brain. Therefore, neuropsychological tests are sensitive to dysfunction of the orbitofrontal cortex, but are not specific to it.
The weakness of these tests is that they do not necessarily show a dysfunction of the orbitofrontal cortex.
To resolve this problem, some researchers combined neuropsychological tests that detect dysfunction in the orbitofrontal cortex thereby increasing its specificity to the degeneration of the frontal lobe in order to detect behavioral variant frontotemporal dementia at an early stage.
They invented the Executive and Social Cognition Battery that comprises five neuropsychological tests.
- Iowa game task.
- Prueba False Step.
- Task of the hotel.
- Mind in the eyes.
- Multiple stage task.
The result has shown that this combined test is more sensitive to detect deficits in frontotemporal dementia of early behavioral variant.
Treatment of frontotemporal dementia
Currently, there is no cure for frontotemporal dementia. Treatments are available to manage behavioral symptoms. Disinhibition and compulsive behaviors can be controlled by selective inhibitors of serotonin reuptake.
Although Alzheimer’s disease and frontotemporal dementia share certain symptoms, they can not be treated with the same pharmacological agents because cholinergic systems are not affected in frontotemporal dementia.
Because frontotemporal dementia often occurs in younger people (ie, in their 40s or 50s), it can severely affect families.
Patients often still have children living in the home. Financially, it can be devastating since the disease attacks at the time of life that often includes the best years of salary.
Personality changes in individuals with frontotemporal dementia are involuntary. The management of the disease is unique for each individual, as different patients with frontotemporal dementia will show different symptoms, sometimes of a rebellious nature.
