New diagnostic criteria known as the Armstrong criteria were proposed in 2013, although the accuracy of these is limited and further research is needed. Criteria * Insidious onset and gradual progression * Lasts 1 year or more * Meets one of the four subtypes: * Possible CBS * FBS or NAV * PSPS plus at least one CBS feature other than limb rigidity or akinesia * No exclusion criteria present * More likely if onset is after age 50 * More likely if no family history (2 or more relatives) * More likely if no genetic mutation affecting T (e.g., MAPT) Possible<unk>  syndrome subtype Symptoms may be symmetric or asymmetric. One or more of: # limb rigidity or akinesia # limb dystonia # limb myoclonus, plus one of: # orobuccal or limb apraxia # cortical sensory deficit # alien limb phenomena (more than simple levitation) More likely (probable sporadic CBS) if: * Asymmetric presentation * Onset after age 50 * No family history (2 or more relatives) * No genetic mutation affecting T (e.g. MAPT) * plus two of: # limb rigidity or akinesia # limb dystonia # limb myoclonus * plus two of: # orobuccal or limb apraxia, # cortical sensory deficit # alien limb phenomena (more than simple levitation) Frontal behavioural-spatial syndrome subtype Two of: # executive dysfunction # behavioural or personality changes # visuospatial deficits NAV of primary progressive aphasia subtype Effortful, agrammatic speech plus at least one of: # impaired grammar/sentence comprehension with relatively preserved single word comprehension or # groping, distorted speech production (apraxia of speech) Progressive supranuclear palsy syndrome subtype Three of: # axial or symmetric limb rigidity or akinesia # postural instability or falls # urinary incontinence # behavioural changes # supranuclear vertical gaze palsy or decreased vertical saccade velocity Exclusion criteria These apply to all types of<unk> . * Evidence of Lewy body disease * multiple system atrophy * Alzheimer's disease * ALS * semantic or logopenic variant primary progressive aphasia * structural lesion suggestive of focal cause * granulin mutation or reduced plasma progranulin levels * TDP-43 or fused in sarcoma (FUS) mutations The diagnostic criteria for clinical use may result in a misdiagnosis of other tau-based diseases. The probable criteria are proposed for clinical research. Clinical vs. postmortem One of the most significant problems associated with<unk>  is the inability to perform a definitive diagnosis while an individual exhibiting the symptoms associated with<unk>  is still alive. A clinical diagnosis of<unk>  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<unk>  is performed, in which other diseases are eliminated based on specific symptoms that do not overlap. However, some of the symptoms of<unk>  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<unk> . Most of these diagnoses utilize the Gallyas-Braak staining method, which is effective in identifying the presence of astroglial inclusions and coincidental tauopathy. Overlap with other diseases Progressive supranuclear palsy (PSP) is frequently the disease most often confused with<unk> . Both PSP and<unk>  result in similar symptoms, and both display tauopathies upon histological inspection. However, it has been noted that tauopathy in PSP results in tuft-shaped astrocytes in contrast with the ring-shaped astrocytic plaques found as a result of<unk> . Individuals diagnosed with PD often exhibit similar movement dysfunction as those diagnosed with<unk> , which adds complexity to its diagnosis. Some other neurodegenerative diseases including Alzheimer's disease (AD), dementia with Lewy bodies (DLB), chronic traumatic encephalopathy (CTE) and frontotemporal dementia (FTD) also show commonalities with<unk> . Neuroimaging The types of imaging techniques that are most prominently utilized when studying and/or diagnosing<unk>  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<unk>  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<unk> , this is not an exclusive indicator for the disease. Thus, the utilization of this factor in the diagnosis of<unk>  should be used only in combination with other clinically present dysfunctions. MRI MRI images are useful in displaying atrophied portions of neuroanatomical positions within the brain. As a result, it is especially effective in identifying regions within different areas of the brain that have been negatively affected due to the complications associated with<unk> . To be specific, MRI of<unk>  typically shows posterior parietal and frontal cortical atrophy with unequal representation in corresponding sides. In addition, atrophy has been noted in the corpus callosum. Functional MRI (fMRI) has been used to evaluate the activation patterns in various regions of the brain of individuals affected with<unk> . Upon the performance of simple finger motor tasks, subjects with<unk>  experienced lower levels of activity in the parietal cortex, sensorimotor cortex, and supplementary motor cortex than those individuals tested in a control group. SPECT SPECT is currently being used to try to detect<unk> . With many patients of<unk> , there are areas in the basal ganglia which have difficulties receiving dopamine, typically asymmetrically. Specifically affected, are dopamine transporters which are presynaptic on the nigrostriatal cells. SPECT is used to detect these abnormalities in Dopamine transporters. Given that many patients have asymmetrical loss of function and metabolism this can help differentiate patients with<unk>  and those with Alzheimer's. SPECT studies of individuals diagnosed with<unk>  involve perfusion analysis throughout the parts of the brain. SPECT evaluation through perfusion observation consists of monitoring blood release into different locations in tissue or organ regions, which, in the case of<unk> , pertains to localized areas within the brain. Tissue can be characterized as experiencing overperfusion, underperfusion, hypoperfusion, or hyperperfusion. Overperfusion and underperfusion relate to a comparison with the overall perfusion levels within the entire body, whereas hypoperfusion and hyperperfusion are calculated in comparison to the blood flow requirements of the tissue in question. In general, the measurements taken for<unk>  using SPECT are referred to as regional cerebral blood flow (rCBF). In general, SPECT reveals hypoperfusion within both the posterior regions of the frontal and parietal lobes. As in images gathered through MRI, SPECT images indicated asymmetry in the presentation of abnormalities throughout the brain. Additional studies have revealed the presence of perfusion anomalies in the thalamus, temporal cortex, basal ganglia, and pontocerebellar (from the pons to the cerebellum) locations within subjects' brains. FDOPA PET Research has suggested that the integrity of the dopamine system in the striatum has been damaged as an effect of<unk> . Current studies employing the use of FDOPA PET scanning (FDOPA PET) as a possible method for identifying<unk>  have focused on analyzing the efficiency of neurons in the striatum that utilize the neurotransmitter dopamine. These studies have concluded that, in general, dopamine uptake was diminished in the caudate and the putamen. This characteristic also has the potential to be useful in distinguishing<unk>  from the similar PD, as individuals having been diagnosed with PD were more likely to have a lower uptake of dopamine than in individuals with<unk> . Other clinical tests or procedures that monitor the presence of dopamine within the brain (β-CIT SPECT and IBZM SPECT) have shown similar findings. β-CIT serves as an indicator for presynaptic dopaminergic neurons, whereas IBZM is a tracer that shows an affinity for the postsynaptic neurons of the same type. Despite agreement with other imaging studies, these two SPECT methods suffer some scrutiny due to better accuracy in other imaging methods. However, β-CIT SPECT has proven to be helpful in distinguishing<unk>  from PSP and multiple system atrophy (MSA).<unk>  syndrome All of the disorders and dysfunctions associated with<unk>  can often be categorized into a class of symptoms that present with the disease of<unk> . These symptoms that aid in clinical diagnosis are collectively referred to as<unk>  syndrome (CBS) or<unk>  syndrome <unk> S). Alzheimer's disease, Pick's disease, FTDP-17 and progressive supranuclear palsy can display a<unk>  syndrome. It has been suggested that the nomenclature of<unk>  only be used for naming the disease after it has received verification through postmortem analysis of the neuropathology. CBS patients with greater temporoparietal<unk>  are more likely to have AD pathology as opposed to frontotemporal lobar<unk> .
Corticobasal degeneration
Progressive supranuclear palsy
Wallerian degeneration
White dot syndromes
Cerebellar degeneration
Central chromatolysis
Tauopathy
Multiple system atrophy