<unk>  refers to a lack of coordinated muscle movements that include gait abnormality and is the cerebellar sign that typifies all spinocerebellar<unk>  (SCA) types, though individuals with<unk>  also develop pyramidal and bulbar signs as the disease progresses. The average age of onset is between 30 and 40 years of age, though exceptions exist. From the first symptoms, duration is typically between one and three decades, where earlier onset correlates with faster progression. Spinocerebellar<unk> <unk> , like other SCAs, often causes dysarthria, a motor disorder of speech often manifest as slurring of words; pathological nystagmus, a disorder in which eyes drift involuntarily affecting vision; and gait and balance issues.<unk>  is also commonly present with dysphagia, a swallowing disorder that can cause choking while eating and drinking; and hypermetric saccades, where the eye tends to move faster or further than intended as it tracks an object or moves from one focus to another. As the disease progresses, more severe neurologic symptoms can appear like dysmetria, where limb movements consistently overshoot the desired position; dysdiadochokinesia, where repeated body movements become uncoordinated; or hypotonia, where muscles atrophy. While new symptoms appear as<unk>  progresses, nystagmus may disappear as eye movements and saccades slow down. Fatality may ultimately be caused by loss of bulbar functions, but complications from symptoms, such as pneumonia from swallowing problems, or trauma from falls, can be fatal as well. The severity and exact phenotype of these symptoms may vary between types of SCA.<unk>  dysarthria may vary in severity depending on the task and is often associated with more strained, strangled or harsh sounding vocalization than that of other disorders. Because of the significant variance between cases of<unk> , typical signs and symptoms may appear alongside more subtle or rare symptoms. Maculopathy has been reported in rare cases, and may be linked effects from the mutation on the ATXN1 locus on genes in neighboring loci. Task specific dystonias have been reported in individual cases, often in the form of writer's cramps or cervical dystonia. SCAs can also be detected before serious atrophy with electrophysiologic techniques, using electrodes on the scalp to detect changes in electric potential within the brain in response to sensations or movements. Individuals with<unk>  often exhibit abnormal brainstem auditory evoked potential, including prolonged latency and absent or poorly defined waveforms, with one study reporting 73.3% of test subjects exhibiting abnormalities. The same study also found abnormalities in visual evoked potential and median somatosensory evoked potential in some<unk>  persons. These results were similar to those exhibited in other SCAs and differences between the SCAs were not statistically significant, so electrophysiologic techniques cannot replace genetic testing for specific diagnoses of SCAs. All SCAs cause atrophy in various neural tissues that are detectable using magnetic resonance imaging, computed tomography, or other imaging techniques. In<unk>  some degradation in the grey matter of the cerebellum and brain stem can sometimes be detected in presymptomatic individuals with the expansion in ATXN1. Typically, grey matter loss can be observed in cerebellar vermis in all lobules of the cerebellum and in the paramedian portions of both hemispheres. White matter loss can also be observed in the middle cerebellar peduncles. The volume loss can be correlated to severity and duration. An estimated 77% of cases of progressive cerebellar disease are reported to have one or more mental health disorders, and<unk> 9% exhibit cognitive disorders. These estimates are consistently higher than the portion with mental health disorders in the general population, but still follow other general patterns, like correlations between depression frequency and sex or age. It is unclear if depression can be linked causally to cerebellar degeneration; one study reports data consistent with depression primarily being a response to the disability, not a symptom of it, while another reports evidence that depression may have a causal link; prevalence of depression varies differently between<unk> ypes than does the rate of progression of disability.
Spinocerebellar ataxia type 1
Spinocerebellar ataxia type 6
Spinocerebellar ataxia type-13
Autosomal recessive cerebellar ataxia type 1
Metachromatic leukodystrophy
Benign hereditary chorea
Stratton Parker syndrome
Friedreich's ataxia