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.

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.

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.

Diagnosis of MSA can be challenging because there is no test that can definitively make or confirm the diagnosis in a living patient. Clinical diagnostic criteria were defined in 1998 and updated in 2007. Certain signs and symptoms of MSA also occur with other disorders, such as Parkinson's disease, making the diagnosis more difficult.

Both MRI and CT scanning frequently show a decrease in the size of the cerebellum and pons in those with cerebellar features. The putamen is hypodense on T2-weighted MRI and may show an increased deposition of iron in Parkinsonian form. In cerebellar form, a "hot cross" sign has been emphasized; it reflects atrophy of the pontocereballar fibers that manifest in T2 signal intensity in atrophic pons.

A definitive diagnosis can only be made pathologically on finding abundant glial cytoplasmic inclusions in the central nervous system.

Computed tomography (CT) scans of people with PD usually appear normal. MRI has become more accurate in diagnosis of the disease over time, specifically through iron-sensitive T2* and SWI sequences at a magnetic field strength of at least 3T, both of which can demonstrate absence of the characteristic 'swallow tail' imaging pattern in the dorsolateral substantia nigra. In a meta-analysis, absence of this pattern was 98% sensitive and 95% specific for the disease. Diffusion MRI has shown potential in distinguishing between PD and Parkinson plus syndromes, though its diagnostic value is still under investigation. CT and MRI are also used to rule out other diseases that can be secondary causes of parkinsonism, most commonly encephalitis and chronic ischemic insults, as well as less frequent entities such as basal ganglia tumors and hydrocephalus.

Dopamine-related activity in the basal ganglia can be directly measured with PET and SPECT scans. A finding of reduced dopamine-related activity in the basal ganglia can rule out drug-induced parkinsonism, but reduced basal ganglia dopamine-related activity is seen in both PD and the Parkinson-plus disorders so these scans are not reliable in distinguishing PD from other neurodegenerative causes of parkinsonism.

A physician will initially assess for Parkinson's disease with a careful medical history and neurological examination. People may be given levodopa, with any resulting improvement in motor impairment helping to confirm the PD diagnosis. The finding of Lewy bodies in the midbrain on autopsy is usually considered final proof that the person had PD. The clinical course of the illness over time may reveal it is not Parkinson's disease, requiring that the clinical presentation be periodically reviewed to confirm accuracy of the diagnosis.

Other causes that can secondarily produce parkinsonism are stroke and drugs. Parkinson plus syndromes such as progressive supranuclear palsy and multiple system atrophy must be ruled out. Anti-Parkinson's medications are typically less effective at controlling symptoms in Parkinson plus syndromes. Faster progression rates, early cognitive dysfunction or postural instability, minimal tremor or symmetry at onset may indicate a Parkinson plus disease rather than PD itself. Genetic forms with an autosomal dominant or recessive pattern of inheritance are sometimes referred to as familial Parkinson's disease or familial parkinsonism.

Medical organizations have created diagnostic criteria to ease and standardize the diagnostic process, especially in the early stages of the disease. The most widely known criteria come from the UK Queen Square Brain Bank for Neurological Disorders and the U.S. National Institute of Neurological Disorders and Stroke. The Queen Square Brain Bank criteria require slowness of movement (bradykinesia) plus either rigidity, resting tremor, or postural instability. Other possible causes of these symptoms need to be ruled out. Finally, three or more of the following supportive features are required during onset or evolution: unilateral onset, tremor at rest, progression in time, asymmetry of motor symptoms, response to levodopa for at least five years, clinical course of at least ten years and appearance of dyskinesias induced by the intake of excessive levodopa.

When PD diagnoses are checked by autopsy, movement disorders experts are found on average to be 79.6% accurate at initial assessment and 83.9% accurate after they have refined their diagnosis at a follow-up examination. When clinical diagnoses performed mainly by nonexperts are checked by autopsy, average accuracy is 73.8%. Overall, 80.6% of PD diagnoses are accurate, and 82.7% of diagnoses using the Brain Bank criteria are accurate.

A task force of the International Parkinson and Movement Disorder Society (MDS) has proposed diagnostic criteria for Parkinson’s disease as well as research criteria for the diagnosis of prodromal disease, but these will require validation against the more established criteria.

Genetic testing can confirm a neuroferritinopathy diagnosis. A diagnosis can be made by analyzing the protein sequences of affected individuals and comparing them to known neuroferritinopathy sequences.

It is possible to detect the signs of Alexander disease with magnetic resonance imaging (MRI), which looks for specific changes in the brain that may be tell-tale signs for the disease. It is even possible to detect adult-onset Alexander disease with MRI. Alexander disease may also be revealed by genetic testing for the known cause of Alexander disease. A rough diagnosis may also be made through revealing of clinical symptoms including, enlarged head size, along with radiological studies, and negative tests for other leukodystrophies.

Blood tests usually come back normal in affected individuals, so they do not serve as a reliable means of diagnosis. Blood tests can show low serum ferritin levels. However, this is unreliable as method of diagnosis, as some patients show typical serum ferritin levels even at the latest stages of neuroferritinopathy. Cerebral spinal fluid tests also are typically normal.

Ferritin found in the skin, liver, kidney, and muscle tissues may help in diagnosing neuroferritinopathy. More cytochrome c oxidase-negative fibers are also often found in the muscle biopsies of affected individuals.

A neurological examination would show evidence of muscle rigidity; weakness; and abnormal postures, movements, and tremors. If other family members are also affected, this may help determine the diagnosis. Genetic tests can confirm an abnormal gene causing the disease. However, this test is not yet widely available. Other movement disorders and diseases must be ruled out. Individuals exhibiting any of the above listed symptoms are often tested using MRI (Magnetic Resonance Imaging) for a number of neuro-related disorders. As PKAN is a disease prominently evident in the brain, MRIs are very useful in making a sound diagnosis. An MRI usually shows iron deposits in the basal ganglia. Development of diagnostic criteria continues in the hope of further separating PKAN from other forms of neurodegenerative diseases featuring NBIA.

Microscopic features of PKAN include:

- Iron granules

- Spheroid bodies

- Lewy bodies within neurons

Parkinson-plus syndromes are usually more rapidly progressive and less likely to respond to antiparkinsonian medication than PD. However, the additional features of the diseases may respond to medications not used in PD.

Current therapy for Parkinson-plus syndromes is centered around a multidisciplinary treatment of symptoms.

These disorders have been linked to pesticide exposure.

There is no cure or treatment for GSS. It can, however, be identified through genetic testing. GSS is the slowest to progress among human prion diseases. Duration of illness can range from 3 months to 13 years, with an average duration of 5 or 6 years.

MSA usually progresses more quickly than Parkinson's disease. There is no remission from the disease. The average remaining lifespan after the onset of symptoms in patients with MSA is 7.9 years. Almost 80% of patients are disabled within five years of onset of the motor symptoms, and only 20% survive past 12 years. Rate of progression differs in every case and speed of decline may vary widely in individual patients.

O’Sullivan and colleagues (2008) identified early autonomic dysfunction to be the most important early clinical prognostic feature regarding survival in MSA. Patients with concomitant motor and autonomic dysfunction within three years of symptom onset had a shorter survival duration, in addition to becoming wheelchair dependent and bed-ridden at an earlier stage than those who developed these symptoms after three years from symptom onset. Their study also showed that when patients with early autonomic dysfunction develop frequent falling, or wheelchair dependence, or severe dysphagia, or require residential care, there is a shorter interval from this point to death.

The prognosis is generally poor. With early onset, death usually occurs within 10 years from the onset of symptoms. Individuals with the infantile form usually die before the age of 7. Usually, the later the disease occurs, the slower its course is.

The symptoms of DLB overlap clinically with those of Alzheimer's disease and Parkinson's disease, but are associated more commonly with the latter. Because of this overlap, early DLB is often misdiagnosed. The overlap of neuropathological and presenting symptoms (cognitive, emotional, and motor) may make an accurate differential diagnosis difficult. In fact, DLB often is confused in its early stages with Alzheimer's disease and/or vascular dementia (multi-infarct dementia). However, while Alzheimer’s disease usually begins gradually, DLB frequently has a rapid or acute onset, with an especially rapid cognitive and physical decline in the first few months. Thus, DLB tends to progress more rapidly than Alzheimer’s disease. Despite the difficulty, a prompt diagnosis is important because of the risks of sensitivity to certain neuroleptic (antipsychotic) medications and because appropriate treatment of symptoms may improve life for both the person with DLB and the person's caregivers.

Dementia with Lewy bodies is distinguished from the dementia that sometimes occurs in Parkinson's disease by the time frame in which dementia symptoms appear relative to Parkinson symptoms. Parkinson's disease with dementia (PDD) would be the diagnosis when the onset of dementia is more than a year after the onset of Parkinsonian symptoms. DLB is diagnosed when cognitive symptoms begin at the same time or within a year of Parkinson symptoms.

FXTAS can be diagnosed using a combination of molecular, clinical, and radiological findings. In order for individuals to acquire FXTAS, they must first be permutation carriers, having between 55-200 CGG trinucleotide repeat expansion of the FMR1 gene. A definite, probable, or possible diagnosis of FXTAS can be assigned based on a clinician's confidence based on combined clinical or radiological findings in conjunction with the molecular permutation.

Clinical findings are divided into major and minor symptoms. Major symptoms include intention tremor and gait ataxia. Minor symptoms such as parkinsonism, short-term memory deficit, and executive function decline can further contribute to a diagnosis of FXTAS. Radiological findings are similarly divided into major and minor categories. As patients with FXTAS can have distinct brain scans from other movement disorders, a scan showing white matter lesions of the middle cerebellar peduncle is a major finding that can be attributed to FXTAS. Overall or generalized brain tissue atrophy and cerebral white matter lesions can also be minor indicators for a diagnosis.

For a definite diagnosis to be made, a major radiological finding and one major clinical finding must be present. Probable diagnosis can be made off either a major radiological finding and a minor clinical finding or two major clinical findings alone. The possible category for diagnosis can be made with a minor radiological finding and a major clinical finding.

There is no cure for GSS, nor is there any known treatment to slow the progression of the disease. However, therapies and medication are aimed at treating or slowing down the effects of the symptoms. Their goal is to try to improve the patient's quality of life as much as possible. Despite there being no cure for GSS, it is possible to undergo testing for the presence of the underlying genetic mutation. Testing for GSS involves a blood and DNA examination in order to attempt to detect the mutated gene at certain codons. If the genetic mutation is present, the patient will eventually be afflicted by GSS, and, due to the genetic nature of the disease, the offspring of the patient are predisposed to a higher risk of inheriting the mutation.

Protein function tests that demonstrate a reduce in chorein levels and also genetic analysis can confirm the diagnosis given to a patient. For a disease like this it is often necessary to sample the blood of the patient on multiple occasions with a specific request given to the haematologist to examine the film for acanthocytes. Another point is that the diagnosis of the disease can be confirmed by the absence of chorein in the western blot of the erythrocyte membranes.

Currently, an estimated 60 to 75% of diagnosed dementias are of the Alzheimer's and mixed (Alzheimer's and vascular dementia) type, 10 to 15% are Lewy body type, with the remaining types being of an entire spectrum of dementias, including frontotemporal lobar degeneration (Pick's disease), alcoholic dementia, pure vascular dementia, etc. Dementia with Lewy bodies tends to be under-recognized. Dementia with Lewy bodies is slightly more prevalent in men than women. DLB increases in prevalence with age; the mean age at presentation is 75 years.

Dementia with Lewy bodies affects about one million individuals in the United States.

Neurodegeneration is the progressive loss of structure or function of neurons, including death of neurons. Many neurodegenerative diseases – including amyotrophic lateral sclerosis, Parkinson's, Alzheimer's, and Huntington's – occur as a result of neurodegenerative processes. Such diseases are incurable, resulting in progressive degeneration and/or death of neuron cells. As research progresses, many similarities appear that relate these diseases to one another on a sub-cellular level. Discovering these similarities offers hope for therapeutic advances that could ameliorate many diseases simultaneously. There are many parallels between different neurodegenerative disorders including atypical protein assemblies as well as induced cell death. Neurodegeneration can be found in many different levels of neuronal circuitry ranging from molecular to systemic.

The process of neurodegeneration is not well understood, so the diseases that stem from it have, as yet, no cures. In the search for effective treatments (as opposed to palliative care), investigators employ animal models of disease to test potential therapeutic agents. Model organisms provide an inexpensive and relatively quick means to perform two main functions: target identification and target validation. Together, these help show the value of any specific therapeutic strategies and drugs when attempting to ameliorate disease severity. An example is the drug Dimebon (Medivation). This drug is in phase III clinical trials for use in Alzheimer's disease, and also recently finished phase II clinical trials for use in Huntington's disease. In March 2010, the results of a clinical trial phase III were released; the investigational Alzheimer's disease drug Dimebon failed in the pivotal CONNECTION trial of patients with mild-to-moderate disease. With CONCERT, the remaining Pfizer and Medivation Phase III trial for Dimebon (latrepirdine) in Alzheimer's disease failed in 2012, effectively ending the development in this indication.

In another experiment using a rat model of Alzheimer's disease, it was demonstrated that systemic administration of hypothalamic proline-rich peptide (PRP)-1 offers neuroprotective effects and can prevent neurodegeneration in hippocampus amyloid-beta 25–35. This suggests that there could be therapeutic value to PRP-1.

Protein degradation offers therapeutic options both in preventing the synthesis and degradation of irregular proteins. There is also interest in upregulating autophagy to help clear protein aggregates implicated in neurodegeneration. Both of these options involve very complex pathways that we are only beginning to understand.

The goal of immunotherapy is to enhance aspects of the immune system. Both active and passive vaccinations have been proposed for Alzheimer's disease and other conditions, however more research must be done to prove safety and efficacy in humans.

Tauopathy belongs to a class of neurodegenerative diseases associated with the pathological aggregation of tau protein in neurofibrillary or gliofibrillary tangles in the human brain. Tangles are formed by hyperphosphorylation of a microtubule-associated protein known as tau, causing it to aggregate in an insoluble form. (These aggregations of hyperphosphorylated tau protein are also referred to as paired helical filaments). The precise mechanism of tangle formation is not completely understood, and it is still controversial as to whether tangles are a primary causative factor in the disease or play a more peripheral role. Primary tauopathies, i.e., conditions in which neurofibrillary tangles (NFT) are predominantly observed, include:

- Primary age-related tauopathy (PART)/Neurofibrillary tangle-predominant senile dementia, with NFTs similar to AD, but without plaques.

- Chronic traumatic encephalopathy, including dementia pugilistica

- Progressive supranuclear palsy

- Corticobasal degeneration

- Frontotemporal dementia and parkinsonism linked to chromosome 17

- Lytico-Bodig disease (Parkinson-dementia complex of Guam)

- Ganglioglioma and gangliocytoma

- Meningioangiomatosis

- Postencephalitic parkinsonism

- Subacute sclerosing panencephalitis

- As well as lead encephalopathy, tuberous sclerosis, Hallervorden-Spatz disease, and lipofuscinosis

Neurofibrillary tangles were first described by Alois Alzheimer in one of his patients suffering from Alzheimer's disease (AD), which is considered a secondary tauopathy. AD is also classified as an amyloidosis because of the presence of senile plaques.

The degree of NFT involvement in AD is defined by Braak stages. Braak stages I and II are used when NFT involvement is confined mainly to the transentorhinal region of the brain, stages III and IV when there's also involvement of limbic regions such as the hippocampus, and V and VI when there's extensive neocortical involvement. This should not be confused with the degree of senile plaque involvement, which progresses differently.

In both Pick's disease and corticobasal degeneration, tau proteins are deposited as inclusion bodies within swollen or "ballooned" neurons.

Argyrophilic grain disease (AGD), another type of dementia, is marked by an abundance of argyrophilic grains and coiled bodies upon microscopic examination of brain tissue. Some consider it to be a type of Alzheimer's disease. It may co-exist with other tauopathies such as progressive supranuclear palsy and corticobasal degeneration, and also Pick's disease.

Huntington's disease (HD): a neurodegenerative disease caused by a CAG tripled expansion in the Huntington gene is the most recently described tauopathy (Fernandez-Nogales et al. Nat Med 2014). JJ Lucas and co-workers demonstrate that, in brains with HD, tau levels are increased and the 4R/3R balance is altered. In addition, the Lucas study shows intranuclear insoluble deposits of tau; these "Lucas' rods" were also found in brains with Alzheimer's disease.

Tauopathies are often overlapped with synucleinopathies, possibly due to interaction between the synuclein and tau proteins.

The non-Alzheimer's tauopathies are sometimes grouped together as "Pick's complex" due to their association with frontotemporal dementia, or frontotemporal lobar degeneration.

The medical management of FXTAS aims to reduce the level of disability and minimize symptoms. Presently, there are many gaps in the research on the management of FXTAS, as the disorder was first described in the literature in 2001. There is no treatment modality aimed at reversing the pathogenesis of FXTAS. However, there are a variety of drug therapies that are being utilized in the management of FXTAS symptoms, although there is a lack of randomized control trials assessing the efficacy these therapies and support is limited to anecdotal evidence. Therefore, many of the treatments are based on what has been helpful in disorders with similar clinical presentations.

There is no cure for FXTAS. Current treatment includes medications for alleviating symptoms of tremor, ataxia, mood changes, anxiety, cognitive decline, dementia, neuropathic pain, or fibromyalgia. Neurological rehabilitation has not been studied for patients with FXTAS but should also be considered as a possible form of therapy. Additionally, occupational and physical therapy may help to improve performance of functional tasks.

Every disease has different signs and symptoms. Some of them are persistent headache; pain in the face, back, arms, or legs; an inability to concentrate; loss of feeling; memory loss; loss of muscle strength; tremors; seizures; increased reflexes, spasticity, tics; paralysis; and slurred speech. One should seek medical attention if affected by these.