Spinocerebellar ataxia type 2 olfactory impairment shows a pattern similar to other major neurodegenerative diseases

Centro para la Investigación y Rehabilitación de las Ataxias Hereditarias Carlos J. Finlay, Holguín, Cuba.
Journal of Neurology (Impact Factor: 3.38). 10/2006; 253(9):1165-9. DOI: 10.1007/s00415-006-0183-2
Source: PubMed


Olfactory function is affected in different neurodegenerative diseases. Recently, it has been found that some hereditary ataxias are also associated with significant olfactory impairment. However, the initial findings did not examine the nature of the olfactory impairment associated with these ataxias. In the present article the effect of spinocerebellar ataxia type 2 (SCA2) on olfactory function was studied in 53 SCA2 patients and 53 healthy control subjects from Holguín, Cuba. Several tests were applied to evaluate olfactory threshold, description, identification and discrimination. The results show significant impairment in SCA2 patients on all olfactory measurements, and the pattern of olfactory deficits found suggests that they have much in common with those reported for other neurodegenerative diseases such as Parkinson's and Alzheimer's diseases.

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    • "Additionally, SCA2 patients show a significant impairment of olfactory threshold, identification and discrimination capabilities. The score of the University of Pennsylvania smell identification test (UPSIT) is significantly reduced and it correlates positively with ataxia score but it is not influenced by the age, age at onset, disease duration and CAG repeats (Velázquez et al, 2006). "

    Spinocerebellar Ataxia, 04/2012; , ISBN: 978-953-51-0542-8
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    • "Spinocerebellar ataxia type 2 (SCA2) is a genetic-based disorder with primary symptoms of progressive gait ataxia, diminished saccade velocity [1], poor coordination of speech musculature (dysarthria), olfactory deficits [2], [3] and absence of neurological reflexes such as the knee jerk reaction (areflexia) [4]–[6]. This polyglutamine (PolyQ) disorder produces severe degeneration of pontine nuclei, inferior olives, and Purkinje cells in the cerebellum [7], [8]. "
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    ABSTRACT: Motor deficits are a critical component of the clinical characteristics of patients with spinocerebellar ataxia type 2. However, there is no current information on the preclinical manifestation of those motor deficits in presymptomatic gene carriers. To further understand and characterize the onset of the clinical manifestation in this disease, we tested presymptomatic spinocerebellar ataxia type 2 gene carriers, and volunteers, in a task that evaluates their motor performance and their motor learning capabilities. 28 presymptomatic spinocerebellar ataxia type 2 gene carriers and an equal number of control volunteers matched for age and gender participated in the study. Both groups were tested in a prism adaptation task known to be sensible to both motor performance and visuomotor learning deficits. Our results clearly show that although motor learning capabilities are intact, motor performance deficits are present even years before the clinical manifestation of the disease start. The results show a clear deficit in motor performance that can be detected years before the clinical onset of the disease. This motor performance deficit appears before any motor learning or clinical manifestations of the disease. These observations identify the performance coefficient as an objective and quantitative physiological biomarker that could be useful to assess the efficiency of different therapeutic agents.
    PLoS ONE 02/2009; 4(4):e5398. DOI:10.1371/journal.pone.0005398 · 3.23 Impact Factor
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    • "First, there are reports of olfactory dysfunction in patients with cerebellar diseases (Connelly et al., 2003; Mainland et al., 2005; Tucker, 1911; Velazquez-Perez et al., 2006). Second, the staggerer mouse, which has abnormalities in the olivocerebellar pathway, is hyposmic (Deiss and Baudoin, 1997; Deiss and Baudoin, 1999). "
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    ABSTRACT: Harmane (1-methyl-9H-pyrido[3,4-b]indole), a neurotoxin, may be an environmental risk factor for essential tremor (ET). Harmane and related chemicals are toxic to the cerebellum. Whether it is through this mechanism (cerebellar toxicity) that harmane leads to ET is unknown. Impaired olfaction may be a feature of cerebellar disease. To determine whether blood harmane concentrations correlate with olfactory test scores in patients with ET. Blood harmane concentrations were quantified using high performance liquid chromatography. Odor identification testing was performed with the University of Pennsylvania Smell Identification Test (UPSIT). In 83 ET cases, higher log blood harmane concentration was correlated with lower UPSIT score (rho=-0.46, p<0.001). 25/40 (62.5%) cases with high log blood harmane concentration (based on a median split) had low UPSIT scores (based on a median split) vs. 12/43 (27.9%) ET cases with low log blood harmane concentration (adjusted odd ratios (OR) 4.04, 95% confidence intervals (CI) 1.42-11.50, p=0.009). When compared with the low log blood harmane tertile, the odds of olfactory dysfunction were 2.64 times higher in cases in the middle tertile and 10.95 times higher in cases in the high tertile. In 69 control subjects, higher log blood harmane concentration was not correlated with lower UPSIT score (rho=0.12, p=0.32). Blood harmane concentrations were correlated with UPSIT scores in ET cases but not controls. These analyses set the stage for postmortem studies to further explore the role of harmane as a cerebellar toxin in ET.
    NeuroToxicology 05/2008; 29(3):460-5. DOI:10.1016/j.neuro.2008.02.013 · 3.38 Impact Factor
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