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

Abstract

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.

Sniffing out the cerebellum: Figure 1

“…In AD and PD, it has been shown that patients show severe deficits in the three olfactory domains that constitute the peripheral and central olfactory systems 5. This has also been shown in SCA2 patients to a lesser extent,12 and in this study,13 suggesting a similar process stretching across the neurodegenerative disorders that targets the central olfactory pathways early in the disease onset. Following on from the series reported here, in these and in a more genetically defined group of patients it would be important to carry out more detailed cognitive testing, including the cerebellar cognitive profile,2 functional imaging and the SS-16 combined with testing of olfactory detection threshold, identification and discrimination.…”

Olfactory impairment in familial ataxias

“…Fernandez-Ruiz et al [13] reported olfactory impairments in 29 patients with autosomal dominant, recessive and sporadic ataxia in comparison to 29 age and gender matched controls, however, they did not correlate the UPSIT with the MMSE scores. Velazquez-Perez et al [25] found that UPSIT scores were lower in a group of 53 SCA 2 patients when compared to 53 controls but when demented subjects were excluded, there was no significant difference in UPSIT scores between groups. Recently, Braga-Neto et al [14] demonstrated olfactory dysfunction in 41 subjects with SCA 3 even when matched for age, gender and MMSE scores.…”

Motor Decline in Clinically Presymptomatic Spinocerebellar Ataxia Type 2 Gene Carriers

“…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].…”