Because<unk>  is progressive, a standard set of diagnostic criteria can be used, which is centered on the disease's evolution. Included in these fundamental features are problems with cortical processing, dysfunction of the basal ganglia, and a sudden and detrimental onset. Psychiatric and cognitive dysfunctions, although present in<unk> , are much less prevalent and lack establishment as common indicators of the presence of the disease. Although<unk>  has a plethora of symptoms, some are more prevalent than others. In a study of 147 patients with<unk> , it was found that all of them had at least one Parkinsonian sign, 95% having two and 93% had some higher order dysfunction (cognitive impairments like acalculia, sensory loss, dementia, neglect, etc.). In a separate study of 14 patients recorded 3 years after the onset of symptoms, many patients had high numbers of motor symptoms. 71% had bradykinesia (slow movements), 64% showed apraxia, 43% reported limb dystonia, and although more cognitive 36% had dementia. In another study of 36, over half had a useless/alien arm and 27% had a gait impediment21. From this, we can see why<unk>  is hard to diagnose. Even if it can be distinguished as different from one of the other similar diseases, the varying combinations of symptoms create a difficult path to diagnosis. Motor and associated cortical dysfunctions Some of the most prevalent symptom types in people exhibiting<unk>  pertain to identifiable movement disorders and problems with cortical processing. These symptoms are initial indicators of the presence of the disease. Each of the associated movement complications typically appears asymmetrically and the symptoms are not observed uniformly throughout the body. For example, a person exhibiting an alien hand syndrome (explained later) in one hand, will not correspondingly display the same symptom in the other hand. Predominant movement disorders and cortical dysfunctions associated with<unk>  include: * Parkinsonism * Alien hand syndrome * Apraxia (ideomotor apraxia and limb-kinetic apraxia) * Aphasia Parkinsonism The presence of parkinsonism as a clinical symptom of<unk>  is largely responsible for complications in developing unique diagnostic criteria for the disease. Other such diseases in which parkinsonism forms an integral diagnostic characteristic are Parkinson's disease (PD) and progressive supranuclear palsy (PSP). Parkinsonism in<unk>  is largely present in an extremity such as the arm, and is always asymmetric. It has been suggested that non-dominant arm is involved more often. Common associated movement dysfunctions that comprise parkinsonism are rigidity, bradykinesia, and gait disorder, with limb rigidity forming the most typical manifestation of parkinsonism in<unk> . Despite being relatively indistinct, this rigidity can lead to disturbances in gait and correlated movements. Bradykinesia in<unk>  occurs when there is notable slowing in the completion of certain movements in the limbs. In an associated study, it was determined that, three years following first diagnosis, 71% of persons with<unk>  demonstrate the presence of bradykinesia. Alien hand syndrome Alien hand syndrome has been shown to be prevalent in roughly 60% of those people diagnosed with<unk> . This disorder involves the failure of an individual to control the movements of their hand, which results from the sensation that the limb is "foreign". The movements of the alien limb are a reaction to external stimuli and do not occur sporadically or without stimulation. The presence of an alien limb has a distinct appearance in<unk> , in which the diagnosed individual may have a "tactile mitgehen". This mitgehen (German, meaning "to go with") is relatively specific to<unk> , and involves the active following of an experimenter's hand by the subject's hand when both hands are in direct contact. Another, rarer form of alien hand syndrome has been noted in<unk> , in which an individual's hand displays an avoidance response to external stimuli. Additionally, sensory impairment, revealed through limb numbness or the sensation of prickling, may also concurrently arise with alien hand syndrome, as both symptoms are indicative of cortical dysfunction. Like most of the movement disorders, alien hand syndrome also presents asymmetrically in those diagnosed with<unk> . Apraxia Ideomotor apraxia (IMA), although clearly present in<unk> , often manifests atypically due to the additional presence of bradykinesia and rigidity in those individuals exhibiting the disorders. The IMA symptom in<unk>  is characterized by the inability to repeat or mimic particular movements (whether significant or random) both with or without the implementation of objects. This form of IMA is present in the hands and arms, while IMA in the lower extremities may cause problems with walking. Those with<unk>  that exhibit IMA may appear to have trouble initiating walking, as the foot may appear to be fixed to floor. This can cause stumbling and difficulties in maintaining balance. IMA is associated with deterioration in the premotor cortex, parietal association areas, connecting white matter tracts, thalamus, and basal ganglia. Some individuals with<unk>  exhibit limb-kinetic apraxia, which involves dysfunction of more fine motor movements often performed by the hands and fingers. Aphasia Aphasia in<unk>  is revealed through the inability to speak or a difficulty in initiating spoken dialogue and falls under the non-fluent (as opposed to fluent or flowing) subtype of the disorder. This may be related to speech impairment such as dysarthria, and thus is not a true aphasia, as aphasia is related to a change in language function, such as difficulty retrieving words or putting words together to form meaningful sentences. The speech and/or language impairments in<unk>  result in disconnected speech patterns and the omission of words. Individuals with this symptom of<unk>  often lose the ability to speak as the disease progresses. Psychiatric and cognitive disorders Psychiatric problems associated with<unk>  often present as a result of the debilitating symptoms of the disease. Prominent psychiatric and cognitive conditions cited in individuals with<unk>  include dementia, depression, and irritability, with dementia forming a key feature that sometimes leads to the misdiagnosis of<unk>  as another cognitive disorder such as Alzheimer's disease (AD). Frontotemporal dementia can be an early feature.
Corticobasal degeneration
Progressive supranuclear palsy
Wallerian degeneration
White dot syndromes
Cerebellar degeneration
Central chromatolysis
Tauopathy
Multiple system atrophy