Saccade velocity as a surrogate disease marker in spinocerebellar ataxia type 2.

We measured in 82 spinocerebellar ataxia type 2 (SCA2) patients and in 80 controls maximal saccade velocity (MSV) and correlated it to polyglutamine expansion size and disease duration. MSV is strongly decreased in SCA2 patients and is influenced mostly by polyglutamine size.

[Dysautonomic features in patients with Cuban type 2 spinocerebellar ataxia]. / Manifestaciones disautonómicas en pacientes de ataxia espinocerebelosa tipo 2 cubana.

INTRODUCTION: Dysautonomic features are the clinical signs and symptoms derived from anomalous functioning of the sympathetic or parasympathetic nervous systems in either the peripheral or central parts. OBJECTIVE: To identify the clinical features related to dysautonomia in a patient with spinocerebellar ataxia with severe functional disability. PATIENTS AND METHODS: We studied a series of cases, including 21 patients with severe disability (confirmed to their bed or wheelchair, unable to walk and totally or partly dependent on other people for essential everyday activities). The patients and their families were closely questioned, and full clinical examination included a test for orthostasia. RESULTS: All patients had some signs of peripheral dysautonomia: all had vasomotor disorders (orthostasia, distal pallor and coldness, Raynaud s phenomenon, etc.), 95.2% (constipation, urinary and rectal incontinence, polachuria, palpitations, tachycardia at rest, etc.), exocrine gland disorders in 71.4% (increased lachrymation, reduced sweating, increased or reduced salivation), 87.5% peripheral tissue nutrition disorders. Similarly, in all patients studied there was evidence of central dysautonomic disorder, with a syndrome of cachexia with bulimia, sleep disorders together with dysregulation of thirst and body temperature. CONCLUSIONS: In patients with type 2 hereditary spinocerebellar ataxia with severe disability there was involvement of the peripheral and central nervous system regulating autonomic function.

[Automatic analysis of the alternate movements of the arms in patients with type 2 spino cellular ataxia]. / Análisis automático de los movimientos alternativos de miembros superiores en pacientes con ataxia espinocerebelosa tipo 2.

INTRODUCTION: A patient with type 2 spino cerebellar ataxia has difficulty in carrying out alternate movements such as pronation and supination. OBJECTIVES. To evaluate the function of an automatized system for measuring disorders of alternate movements. PATIENTS AND METHODS: We studied the measurement of diadochokinesia in two groups of healthy patients, a first group (64 persons) to determine the normal intervals and a second group to validate the test (52 persons). We also studied 100 patients for validation of the system. A further 53 patients were evaluated before and after rehabilitation. RESULTS: Analysis of the basic measurements for diagnosis of duodochokinesia showed that the higher the cut off point, the greater the sensitivity of the test, whereas the opposite occurred with the specificity. Thus, regarding a higher cut off, there is a five times greater probability of a positive results in the patients than in healthy persons. However, the probability of a normal result is six times higher in healthy than in affected persons. The results of variant analysis done on patients before and after rehabilitation suggest that the presence of quantitative changes in the second study was due to the positive effect of neuro rehabilitation. CONCLUSION: The technique used is effective for differentiation of affected from healthy persons and its use is justified in the evaluation of co ordination ability after rehabilitation

[Spinocerebellar ataxia type 2 in Cuba. A study of the electrophysiological phenotype and its correlation with clinical and molecular variables]. / Ataxia espinocerebelosa tipo 2 en cuba. Estudio del fenotipo electrofisiológico y su correlación con variables clínicas y moleculares.

INTRODUCTION: The spinocerebellar ataxia type 2 has a prevalence of 43 per 100,000 inhabitants in Holguín province, which is the highest one reported worldwide. It is due to an intergenerational CAG repeat expansion contained in the first exon of disease causing gene, and it is characterized by a high variability in its clinical and electrophysiological presentation, even intrafamiliarly. OBJECTIVE: Factors identification, which explains this variability, could lead to the findings of therapeutical ways that may retard the disease onset. PATIENTS AND METHODS: We have done this research in order to contribute to this phenotypic variability knowledge of the different structures and functions of the nervous system. RESULTS: By means of molecular and electrophysiological studies we have found two groups well differentiated in a 52-patient sample. The first one was characterized by CAG repeat expansions above 41 units and by the total blockade of the afferent conduction that is, basic electrophysiological alteration with axonal damage predominance. The second one was characterized by CAG repeat expansions lower or equal to 41 units and showed a high variability in it s electrophysiological behavior with myelinic damage predominance. We realized of the existence of statistical significance correlations between the electrophysiological, clinical and molecular variables considered. CONCLUSIONS: These findings suggest that for by CAG repeat expansions lower or equal to 41 units should be affecting other genetics and/or environmental factors that explain the variability found in this group which are not significant for clinical and electrophysiological presentation in individuals with CAG repeat expansions above 41 units.

Saccade velocity is reduced in presymptomatic spinocerebellar ataxia type 2.

OBJECTIVE: A characteristic feature of spinocerebellar ataxia type 2 (SCA2) is saccadic slowing at early disease stages. We sought to determine whether this sign is detectable before clinical manifestation and quantifies the disease progression throughout life in linear fashion. METHODS: In a specialized ataxia clinic, 54 presymptomatic carriers of SCA2 polyglutamine expansions and 56 relatives without mutation were documented with regard to their maximal saccade velocity (MSV). RESULTS: Among the control individuals, a significant effect of aging on MSV was observed. After elimination of this age influence through a matched-pair approach, a presymptomatic decrease of MSV could be shown. The MSV reduction was stronger in carriers of large expansions. In the years before calculated disease manifestation, the MSV impairment advanced insidiously. CONCLUSION: Saccade velocity is a sensitive SCA2 endophenotype that reflects early pontine degeneration and may be a useful diagnostic parameter before the onset of ataxia. SIGNIFICANCE: Future neuroprotective therapies of polyglutamine neurodegeneration may be assessed by MSV from earliest to prefinal disease stages.