Impact of disease duration on functional status of patients with spinocerebellar ataxia type 2

Functionality and disease severity in spinocerebellar ataxias

ABSTRACT Background: Spinocerebellar ataxias (SCAs) are a group of neurodegenerative diseases characterized by deterioration of balance and functionality that tends to follow disease progression. There is no established link between formal clinical markers for severity and functional/balance scores that could guide rehabilitation teams. Objective: To evaluate the relationship between functional scales and ataxia severity in order to identify cutoff landmarks for functional loss and estimate the mean SARA (Scale for Assessment and Rating of Ataxia) score for the risk ratings for falls on the BBS (Berg Balance Scale). Methods: Consecutive patients with a molecular diagnosis of SCA (total 89: 31 with SCA2 and 58 with SCA3) were assessed for functionality FIM-ADL (Functional Independence Measure-activities of daily living and Lawton-IADL (instrumental activities of daily living), balance (BBS) and disease severity (SARA). Results: The main disability cutoff landmarks were that the need for supervision for FIM-ADL starts with 12 points on SARA and the need for supervision for Lawton-IADL starts with 14 points on SARA. The first items to require assistance were “expression” and “shopping”, respectively. At 20 points on SARA, patients were dependent on all FIM and Lawton items. The item with the greatest impact on distinguishing dependents from independents was “means of transport” in Lawton-IADL and the domain “locomotion” in FIM-ADL. The mean SARA score for patients classified as low risk in the BBS was 9.9 points, and it was 17.4 for medium risk and 25.2 for high risk. Conclusions: Analysis on the correlation between the severity of ataxia and functional scales can form an important guide for understanding the progression of functional dependence among individuals with SCAs.

Ophthalmic Manifestations and Genetics of the Polyglutamine Autosomal Dominant Spinocerebellar Ataxias: A Review

Spinocerebellar ataxia (SCA) is a part of the cerebellar neurodegenerative disease group that is diverse in genetics and phenotypes. It usually shows autosomal dominant inheritance. SCAs, always together with the cerebellar degeneration, may exhibit clinical deficits in brainstem or eye, especially retina or optic nerve. Interestingly, autosomal dominant SCAs share a common genetic mechanism; the length of the glutamine chain is abnormally expanded due to the increase in the cytosine–adenine–guanine (CAG) repeats of the disease causing gene. Studies have suggested that the mutant ataxin induces alteration of protein conformation and abnormal aggregation resulting in nuclear inclusions, and causes cellular loss of photoreceptors through a toxic effect. As a result, these pathologic changes induce a downregulation of genes involved in the phototransduction, development, and differentiation of photoreceptors such as CRX, one of the photoreceptor transcription factors. However, the exact mechanism of neuronal degeneration by mutant ataxin restricted to only certain type of neuronal cell including cerebellar Purkinje neurons and photoreceptor is still unclear. The most common SCAs are types 1, 2, 3, 6, 7, and 17 which contain about 80% of autosomal dominant SCA cases. Various aspects of eye movement abnormalities are evident depending on the degree of cerebellar and brainstem degeneration in SCAs. In addition, certain types of SCAs such as SCA7 are characterized by both cerebellar ataxia and visual loss mainly due to retinal degeneration. The severity of the retinopathy can vary from occult macular photoreceptor disruption to extensive retinal atrophy and is correlated with the number of CAG repeats. The value of using optical coherence tomography in conjunction with electrodiagnostic and genetic testing is emphasized as the combination of these tests can provide critical information regarding the etiology, morphological evaluation, and functional significances. Therefore, ophthalmologists need to recognize and differentiate SCAs in order to properly diagnose and evaluate the disease. In this review, we have described and discussed SCAs showing ophthalmic abnormalities with particular attention to their ophthalmic features, neurodegenerative mechanisms, genetics, and future perspectives.

Assessment of ventilatory function in patients with spinocerebellar ataxia type 2

BACKGROUND

Subclinical ventilatory dysfunction is observed in individuals with spinocerebellar ataxias (SCA). No studies have correlated ventilatory dysfunction to clinical and functional decline in SCA2.

OBJECTIVE

To evaluate the relationship between the values of peak expiratory flow (PEF), maximum inspiratory pressure (MIP), and presence of respiratory complaints with age, disease duration, age at onset of symptoms, balance scores, independence in basic (ADL) and instrumental (IADL) Activities of Daily Living (ADLs), and severity of ataxia (SARA) in individuals with SCA2.

METHODS

Cross-sectional study evaluating age, disease duration, age at onset of symptoms, scores in the Berg Balance Scale and in the SARA, Functional Independence Measure and Lawton's scale, values of PEF and MIP, and the presence of respiratory complaints.

RESULTS

The study included 36 individuals with SCA2, with a mean age of 42.5±2.4 years, disease duration of 7.6±8.2 years, age 33.7±11.5 years at onset of symptoms, and 9.9±10.3 points in the SARA scale. The lowest PEF values correlated with the longer disease duration (p=0.021). The lowest values of PEF and MIP correlated with greater balance impairment (p=0.019 and p=0.045, respectively), increased degree of dependence in the ADL (p=0.006 and p=0.050, respectively) and IADL (p=0.003 and p=0.001, respectively) scales, and highest severity of ataxia (p=0.00 and p=0.017, respectively). Respiratory complaints were observed in 12 (33.3%) individuals and were not related to age, disease duration, age at onset of symptoms, balance, independence, ataxia severity, or PEF and MIP values.

CONCLUSION

Ventilatory dysfunction, even when asymptomatic, is related to balance impairment, independence, and ataxia severity in individuals with SCA2.

Molecular Mechanisms and Therapeutics for Spinocerebellar Ataxia Type 2

The effective therapeutic treatment and the disease-modifying therapy for spinocerebellar ataxia type 2 (SCA2) (a progressive hereditary disease caused by an expansion of polyglutamine in the ataxin-2 protein) is not available yet. At present, only symptomatic treatment and methods of palliative care are prescribed to the patients. Many attempts were made to study the physiological, molecular, and biochemical changes in SCA2 patients and in a variety of the model systems to find new therapeutic targets for SCA2 treatment. A better understanding of the uncovered molecular mechanisms of the disease allowed the scientific community to develop strategies of potential therapy and helped to create some promising therapeutic approaches for SCA2 treatment. Recent progress in this field will be discussed in this review article.

Quality of life in individuals with spinocerebellar ataxia type 10: a preliminary study

ABSTRACT Spinocerebellar ataxia type 10 (SCA10) is characterized by gait ataxia, dysarthria, nystagmus, epilepsy, reduced cognitive ability and depression, which lead to functional loss and behavioral changes. These signs gradually evolve and may interfere with the physical, emotional, and social aspects of quality of life (QoL). Objective: To assess the self-perception of quality of life and its association with disease duration, severity of ataxia, balance and functional independence. Methods: This study focused on the disease duration, ataxia severity (SARA), balance (Berg Balance Scale), functionality (FIM, Lawton IADL) and QoL (SF-36 v.2) of 15 individuals with SCA10. Results: The population sample consisted of eight females and seven males, with a mean age of 43.8 (± 8.2) years, mean age of symptom onset of 33.1 (± 8.9) years and mean disease duration of 9.8 (± 11.2) years. The mean Berg Balance Scale score was 47.2 (± 12), mean SARA score (n = 14) 11.5 (± 7.3), mean Lawton IADL score 20.4 (± 1.8) and mean FIM score 120.3 (± 5.4). Individuals with SCA10 had a greater impairment of QoL in the “role-physical” domain (p = 0.04). The longer the disease duration (p = 0.02), risk of falling (p = 0.04), severity of ataxia (p = 0.00) and functional dependence in activities of daily living (p = 0.03) and instrumental activities of daily living (p = 0.00), the worse the QoL was in the “physical functioning” domain, with a decrease of 1.62 points for each year of disease duration. Conclusion: In this sample, the greatest impairment of QoL in individuals with SCA10 was observed in “physical functioning” and “physical role”.