Treatment for speech disorder in Friedreich ataxia and other hereditary ataxia syndromes

Background Hereditary ataxia syndromes can result in significant speech impairment, a symptom thought to be responsive to treatment. The type of speech impairment most commonly reported in hereditary ataxias is dysarthria. Dysarthria is a collective term referring to a group of movement disorders affecting the muscular control of speech. Dysarthria affects the ability of individuals to communicate and to participate in society. This in turn reduces quality of life. Given the harmful impact of speech disorder on a person's functioning, treatment of speech impairment in these conditions is important and evidence‐based interventions are needed. Objectives To assess the effects of interventions for speech disorder in adults and children with Friedreich ataxia and other hereditary ataxias. Search methods On 14 October 2013, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE, EMBASE, CINAHL Plus, PsycINFO, Education Resources Information Center (ERIC), Linguistics and Language Behavior s (LLBA), Dissertation s and trials registries. We checked all references in the identified trials to identify any additional published data. Selection criteria We considered for inclusion randomised controlled trials (RCTs) or quasi‐RCTs that compared treatments for hereditary ataxias with no treatment, placebo or another treatment or combination of treatments, where investigators measured speech production. Data collection and analysis Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias of included studies using the standard methodological procedures expected by The Cochrane Collaboration. The review authors collected information on adverse effects from included studies. We did not conduct a meta‐analysis as no two studies utilised the same assessment procedures within the same treatment. Main results Fourteen clinical trials, involving 721 participants, met the criteria for inclusion in the review. Thirteen studies compared a pharmaceutical treatment with placebo (or a low dose of the intervention), in heterogenous groups of degenerative cerebellar ataxias. Three compounds were studied in two trials each: a levorotatory form of 5‐hydroxytryptophan (L‐5HT), idebenone and thyrotropin‐releasing hormone tartrate (TRH‐T); each of the other compounds (riluzole, varenicline, buspirone, betamethasone, coenzyme Q10 with vitamin E, α‐tocopheryl quinone and erythropoietin) were studied in one