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In diagnosing autosomal dominant cerebellar ataxia the individuals clinical history or their past health examinations, a current physical examination to check for any physical abnormalities, and a genetic screening of the patients genes and the genealogy of the family are done. The large category of cerebellar ataxia is caused by a deterioration of neurons in the cerebellum, therefore magnetic resonance imaging (MRI) is used to detect any structural abnormality such as lesions which are the primary cause of the ataxia. Computed tomography (CT) scans can also be used to view neuronal deterioration, but the MRI provides a more accurate and detailed picture.
Prenatal screening is not typically done for FHM, however it may be performed if requested. As penetrance is high, individuals found to carry mutations should be expected to develop signs of FHM at some point in life.
The types of imaging techniques that are most prominently utilized when studying and/or diagnosing CBD are:
- magnetic resonance imaging (MRI)
- single-photon emission computed tomography (SPECT)
- fluorodopa positron emission tomography (FDOPA PET)
Developments or improvements in imaging techniques provide the future possibility for definitive clinical diagnosis prior to death. However, despite their benefits, information learned from MRI and SPECT during the beginning of CBD progression tend to show no irregularities that would indicate the presence of such a neurodegenerative disease. FDOPA PET is used to study the efficacy of the dopamine pathway.
Despite the undoubted presence of cortical atrophy (as determined through MRI and SPECT) in individuals experiencing the symptoms of CBD, this is not an exclusive indicator for the disease. Thus, the utilization of this factor in the diagnosis of CBD should be used only in combination with other clinically present dysfunctions.
Transneuronal degeneration is the death of neurons resulting from the disruption of input from or output to other nearby neurons. It is an active excitotoxic process when a neuron is overstimulated by a neurotransmitter (most commonly glutamate) causing the dysfunction of that neuron (either damaging it or killing it) which drives neighboring neurons into metabolic deficit, resulting in rapid, widespread loss of neurons. This can be either anterograde or retrograde, indicating the direction of the degeneration relative to the original site of damage (see types). There are varying causes for transneuronal degeneration such as brain lesions, disconnection syndromes, respiratory chain deficient neuron interaction, and lobectomies. Although there are different causes, transneuronal degeneration generally results in the same effects (whether they be cellular, dendritic, or axonal) to varying degrees. Transneuronal degeneration is thought to be linked to a number of diseases, most notably Huntington's disease and Alzheimer's disease, and researchers recently have been performing experiments with monkeys and rats, monitoring lesions in different parts of the body to study more closely how exactly the process works.
One of the most significant problems associated with CBD is the inability to perform a definitive diagnosis while an individual exhibiting the symptoms associated with CBD is still alive. A clinical diagnosis of CBD is performed based upon the specified diagnostic criteria, which focus mainly on the symptoms correlated with the disease. However, this often results in complications as these symptoms often overlap with numerous other neurodegenerative diseases. Frequently, a differential diagnosis for CBD is performed, in which other diseases are eliminated based on specific symptoms that do not overlap. However, some of the symptoms of CBD used in this process are rare to the disease, and thus the differential diagnosis cannot always be used.
Postmortem diagnosis provides the only true indication of the presence of CBD. Most of these diagnoses utilize the Gallyas-Braak staining method, which is effective in identifying the presence of astroglial inclusions and coincidental tauopathy.
Transneuronal degeneration can be grouped into two general categories: anterograde and retrograde.
Diagnosis of FHM is made according to the following criteria:
- Two attacks of each of the following:
- At least one close (first or second degree) relative with FHM
- No other likely cause
Sporadic forms follow the same diagnostic criteria, with the exception of family history.
In all cases, family and patient history is used for diagnosis. Brain imaging techniques, such as MRI, CAT scans and SPECT, are used to look for signs of other familial conditions such as CADASIL or mitochondrial disease, and for evidence of cerebellar degeneration. With the discovery of causative genes, genetic sequencing can also be used to verify diagnosis (though not all genetic loci are known).
In terms of a cure there is currently none available, however for the disease to manifest itself, it requires mutant gene expression. Manipulating the use of protein homoestasis regulators can be therapuetic agents, or a treatment to try and correct an altered function that makes up the pathology is one current idea put forth by Bushart, et al. There is some evidence that for SCA1 and two other polyQ disorders that the pathology can be reversed after the disease is underway. There is no effective treatments that could alter the progression of this disease, therefore care is given, like occupational and physical therapy for gait dysfunction and speech therapy.
Diagnosis requires a neurological examination and neuroimaging can be helpful.
BVVL can be differentially diagnosed from similar conditions like Fazio-Londe syndrome and amyotrophic lateral sclerosis, in that those two conditions don't involve sensorineural hearing loss, while BVVL, Madras motor neuron disease, Nathalie syndrome, and Boltshauser syndrome do. Nathalie syndrome does not involve lower cranial nerve symptoms, so it can be excluded if those are present. If there is evidence of lower motor neuron involvement, Boltshauser syndrome can be excluded. Finally, if there is a family history of the condition, then BVVL is more likely than MMND, as MMND tends to be sporadic.
Genetic testing is able to identify genetic mutations underying BVVL.
The confirmatory diagnosis is made via brain biopsy, however, other tests can be used to help such as MRI, EEG, CT, as well as the physical exam and history
In regards to the diagnosis of spinal and bulbar muscular atrophy, the "AR Xq12" gene is the focus. Many mutations are reported and identified as missense/nonsense, that can be identified with 99.9% accuracy. Test for this gene in the majority of affected patients yields the diagnosis.
A 2006 study followed 223 patients for a number of years. Of these, 15 died, with a median age of 65 years. The authors tentatively concluded that this is in line with a previously reported estimate of a shortened life expectancy of 10-15 years (12 in their data).
The clinical course of BVVL can vary from one patient to another. There have been cases with progressive deterioration, deterioration followed by periods of stabilization, and deterioration with abrupt periods of increasing severity.
The syndrome has previously been considered to have a high mortality rate but the initial response of most patients to the Riboflavin protocol are very encouraging and seem to indicate a significantly improved life expectancy could be achievable. There are three documented cases of BVVL where the patient died within the first five years of the disease. On the contrary, most patients have survived more than 10 years after the onset of their first symptom, and several cases have survived 20–30 years after the onset of their first symptom.
Families with multiple cases of BVVL and, more generally, multiple cases of infantile progressive bulbar palsy can show variability in age of disease onset and survival. Dipti and Childs described such a situation in which a family had five children that had Infantile PBP. In this family, three siblings showed sensorineural deafness and other symptoms of BVVL at an older age. The other two siblings showed symptoms of Fazio-Londe disease and died before the age of two.
The progression of the degeneration caused by bvFTD may follow a predictable course. The degeneration begins in the orbitofrontal cortex and medial aspects such as ventromedial cortex. In later stages, it gradually expands its area to the dorsolateral cortex and the temporal lobe. Thus, the detection of dysfunction of the orbitofrontal cortex and ventromedial cortex is important in the detection of early stage bvFTD. As stated above, a behavioural change may occur before the appearance of any atrophy in the brain in the course of the disease. Because of that, image scanning such as MRI can be insensitive to the early degeneration and it is difficult to detect early-stage bvFTD.
In neuropsychology, there is an increasing interest in using neuropsychological tests such as the Iowa gambling task or Faux Pas Recognition test as an alternative to imaging for the diagnosis of bvFTD. Both the Iowa gambling task and the Faux Pas test are known to be sensitive to dysfunction of the orbitofrontal cortex.
Faux Pas Recognition test is intended to measure one’s ability to detect faux pas types of social blunders (accidentally make a statement or an action that offends others). It is suggested that people with orbitofrontal cortex dysfunction show a tendency to make social blunders due to a deficit in self-monitoring. Self-monitoring is the ability of individuals to evaluate their behaviour to make sure that their behaviour is appropriate in particular situations. The impairment in self-monitoring leads to a lack of social emotion signals. The social emotions such as embarrassment are important in the way that they signal the individual to adapt social behaviour in an appropriate manner to maintain relationships with others. Though patients with damage to the OFC retain intact knowledge of social norms, they fail to apply it to actual behaviour because they fail to generate social emotions that promote adaptive social behaviour.
The other test, the Iowa gambling task, is a psychological test intended 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 uncertain decisions, they employ both cognitive and emotional processes to assess the values of the choices available to them. Each time a person makes a decision, both physiological signals and evoked emotion (somatic marker) are associated with their outcomes and it accumulates as experience. People tend to choose the choice which might produce the outcome reinforced with positive stimuli, thus it biases decision-making towards certain behaviours while avoiding others. It is thought that somatic marker is processed in orbitofrontal cortex.
The symptoms observed in bvFTD are caused by dysfunction of the orbitofrontal cortex, thus these two neuropsychological tests might be useful in detecting the early stage bvFTD. However, as self-monitoring and somatic marker processes are so complex, it likely involves other brain regions. Therefore, neuropsychological tests are sensitive to the dysfunction of orbitofrontal cortex, yet not specific to it. The weakness of these tests is that they do not necessarily show dysfunction of the orbitofrontal cortex.
In order to solve this problem, some researchers combined neuropsychological tests which detect the dysfunction of orbitofrontal cortex into one so that it increases its specificity to the degeneration of the frontal lobe in order to detect the early-stage bvFTD. They invented the Executive and Social Cognition Battery which comprises five neuropsychological tests.
- Iowa gambling task
- Faux Pas test
- Hotel task
- Mind in the Eyes
- Multiple Errands Task
The result has shown that this combined test is more sensitive in detecting the deficits in early bvFTD.
Accurate diagnosis of these Parkinson-plus syndromes is improved when precise diagnostic criteria are used. Since diagnosis of individual Parkinson-plus syndromes is difficult, the prognosis is often poor. Proper diagnosis of these neurodegenerative disorders is important as individual treatments vary depending on the condition. The nuclear medicine SPECT procedure using I-IBZM, is an effective tool in the establishment of the differential diagnosis between patients with PD and Parkinson-plus syndromes.
There is no cure for spinocerebellar ataxia, which is currently considered to be a progressive and irreversible disease, although not all types cause equally severe disability.
In general, treatments are directed towards alleviating symptoms, not the disease itself. Many patients with hereditary or idiopathic forms of ataxia have other symptoms in addition to ataxia. Medications or other therapies might be appropriate for some of these symptoms, which could include tremor, stiffness, depression, spasticity, and sleep disorders, among others. Both onset of initial symptoms and duration of disease are variable. If the disease is caused by a polyglutamine trinucleotide repeat CAG expansion, a longer expansion may lead to an earlier onset and a more radical progression of clinical symptoms. Typically, a person afflicted with this disease will eventually be unable to perform daily tasks (ADLs). However, rehabilitation therapists can help patients to maximize their ability of self-care and delay deterioration to certain extent. Researchers are exploring multiple avenues for a cure including RNAi and the use of Stem Cells and several other avenues.
On January 18, 2017 BioBlast Pharma announced completion of Phase 2a clinical trials of their medication, Trehalose, in the treatment of SCA3. BioBlast has received FDA Fast Track status and Orphan Drug status for their treatment. The information provided by BioBlast in their research indicates that they hope this treatment may prove efficacious in other SCA treatments that have similar pathology related to PolyA and PolyQ diseases.
In addition, Dr. Beverly Davidson has been working on a methodology using RNAi technology to find a potential cure for over 2 decades. Her research began in the mid-1990s and progressed to work with mouse models about a decade later and most recently has moved to a study with non-human primates. The results from her most recent research "are supportive of clinical application of this gene therapy". Dr. Davidson along with Dr. Pedro Gonzalez-Alegre are currently working to move this technique into a Phase 1 clinical trial.
Finally, another gene transfer technology discovered in 2011 has also been shown by Dr. Davidson to hold great promise and offers yet another avenue to a potential future cure.
Physical therapists can assist patients in maintaining their level of independence through therapeutic exercise programmes. One recent research report demonstrated a gain of 2 SARA points (Scale for the Assessment and Rating of Ataxia) from physical therapy. In general, physical therapy emphasises postural balance and gait training for ataxia patients. General conditioning such as range-of-motion exercises and muscle strengthening would also be included in therapeutic exercise programmes. Research showed that spinocerebellar ataxia 2 (SCA2) patients with a mild stage of the disease gained significant improvement in static balance and neurological indices after six months of a physical therapy exercise training program. Occupational therapists may assist patients with incoordination or ataxia issues through the use of adaptive devices. Such devices may include a cane, crutches, walker, or wheelchair for those with impaired gait. Other devices are available to assist with writing, feeding, and self care if hand and arm coordination are impaired. A randomised clinical trial revealed that an intensive rehabilitation program with physical and occupational therapies for patients with degenerative cerebellar diseases can significantly improve functional gains in ataxia, gait, and activities of daily living. Some level of improvement was shown to be maintained 24 weeks post-treatment. Speech language pathologists may use both behavioral intervention strategies as well as augmentative and alternative communication devices to help patients with impaired speech.
Currently, there is no cure for FTD. Treatments are available to manage the behavioral symptoms. Disinhibition and compulsive behaviors can be controlled by selective serotonin reuptake inhibitors (SSRIs). Although Alzheimer's and FTD share certain symptoms, they cannot be treated with the same pharmacological agents because the cholinergic systems are not affected in FTD.
Because FTD often occurs in younger people (i.e. in their 40's or 50's), it can severely affect families. Patients often still have children living in the home. Financially, it can be devastating as the disease strikes at the time of life that often includes the top wage-earning years.
Personality changes in individuals with FTD are involuntary. Managing the disease is unique to each individual, as different patients with FTD will display different symptoms, sometimes of rebellious nature.
The importance of correctly recognizing progressive muscular atrophy as opposed to ALS is important for several reasons.
- 1) the prognosis is a little better. A recent study found the 5-year survival rate in PMA to be 33% (vs 20% in ALS) and the 10-year survival rate to be 12% (vs 6% in ALS).
- 2) Patients with PMA do not suffer from the cognitive change identified in certain groups of patients with MND.
- 3) Because PMA patients do not have UMN signs, they usually do not meet the "World Federation of Neurology El Escorial Research Criteria" for “Definite” or “Probable” ALS and so are ineligible to participate in the majority of clinical research trials such as drugs trials or brain scans.
- 4) Because of its rarity (even compared to ALS) and confusion about the condition, some insurance policies or local healthcare policies may not recognize PMA as being the life-changing illness that it is. In cases where being classified as being PMA rather than ALS is likely to restrict access to services, it may be preferable to be diagnosed as "slowly progressive ALS" or "lower motor neuron predominant" ALS.
An initial diagnosis of PMA could turn out to be slowly progressive ALS many years later, sometimes even decades after the initial diagnosis. The occurrence of upper motor neurone symptoms such as brisk reflexes, spasticity, or a Babinski sign would indicate a progression to ALS; the correct diagnosis is also occasionally made on autopsy.
There are 3 main histological subtypes found at post-mortem:
- FTLD-tau is characterised by tau positive inclusions often referred to as Pick-bodies. Examples of FTLD-tau include; Pick's disease, corticobasal degeneration, progressive supranuclear palsy.
- FTLD-TDP (or FTLD-U ) is characterised by ubiquitin and TDP-43 positive, tau negative, FUS negative inclusions. The pathological histology of this subtype is so diverse it is subdivided into four subtypes based on the detailed histological findings:
Two physicians independently categorized the various forms of TDP-43 associated disorders. Both classifications were considered equally valid by the medical community, but the physicians in question have jointly proposed a compromise classification to avoid confusion.
- FTLD-FUS; which is characterised by FUS positive cytoplasmic inclusions, intra nuclear inclusions, and neuritic threads. All of which are present in the cortex, medulla, hippocampus, and motor cells of the spinal cord and XIIth cranial nerve.
Dementia lacking distinctive histology (DLDH) is a rare and controversial entity. New analyses have allowed many cases previously described as DLDH to be reclassified into one of the positively defined subgroups.
Frontotemporal lobar degeneration (FTLD) is a pathological process that occurs in frontotemporal dementia. It is characterized by atrophy in the frontal lobe and temporal lobe of the brain, with sparing of the parietal and occipital lobes.
Common proteinopathies that are found in FTLD include the accumulation of Tau proteins and TARDBPs. Mutations in the C9orf72 gene have been established as a major genetic contribution of FTLD, although defects in the GRN and MAPT genes are also associated with it.
Electrical stimulation can promote nerve regeneration. The frequency of stimulation is an important factor in the success of both quality and quantity of axon regeneration as well as growth of the surrounding myelin and blood vessels that support the axon. Histological analysis and measurement of regeneration showed that low frequency stimulation had a more successful outcome than high frequency stimulation on regeneration of damaged sciatic nerves.
Surgery can be done in case a nerve has become cut or otherwise divided. Recovery of a nerve after surgical repair depends mainly on the age of the patient. Young children can recover close-to-normal nerve function. In contrast, a patient over 60 years old with a cut nerve in the hand would expect to recover only protective sensation, that is, the ability to distinguish hot/cold or sharp/dull. Many other factors also affect nerve recovery. The use of autologous nerve grafting procedures that involve redirection of regenerative donor nerve fibers into the graft conduit has been successful in restoring target muscle function. Localized delivery of soluble neurotrophic factors may help promote the rate of axon regeneration observed within these graft conduits.
An expanding area of nerve regeneration research deals with the development of scaffolding and bio-conduits. Scaffolding developed from biomaterial would be useful in nerve regeneration if they successfully exhibit essentially the same role as the endoneurial tubes and Schwann cell do in guiding regrowing axons.
The serum creatine phosphokinase (CPK) can be mildly elevated. While the CPK is often a good marker for damage to muscle tissue, it is not a helpful marker in CIP/CIM, because CIP/CIM is a gradual process and does not usually involve significant muscle cell death (necrosis). Also, even if necrosis is present, it may be brief and is therefore easily missed. If a lumbar puncture (spinal tap) is performed, the protein level in the cerebral spinal fluid would be normal.
Initial screening for CIP/CIM may be performed using an objective scoring system for muscle strength. The Medical Research Council (MRC) score is one such tool, and sometimes used to help identify CIP/CIM patients in research studies. The MRC score involves assessing strength in 3 muscle groups in the right and left sides of both the upper and lower extremities. Each muscle tested is given a score of 0-5, giving a total possible score of 60. An MRC score less than 48 is suggestive of CIP/CIM. However, the tool requires that patients be awake and cooperative, which is often not the case. Also, the screening tool is non-specific, because it does not identify the cause a person's muscle weakness.
Once weakness is detected, the evaluation of muscle strength should be repeated several times. If the weakness persists, then a muscle biopsy, a nerve conduction study (electrophysiological studies), or both should be performed.
PMA is a diagnosis of exclusion, there is no specific test which can conclusively establish whether a patient has the condition. Instead, a number of other possibilities have to be ruled out, such as multifocal motor neuropathy or spinal muscular atrophy. Tests used in the diagnostic process include MRI, clinical examination, and EMG. EMG tests in patients who do have PMA usually show denervation (neurone death) in most affected body parts, and in some unaffected parts too.
It typically takes longer to be diagnosed with PMA than ALS, an average of 20 months for PMA vs 15 months in ALS/MND.