***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND AND PURPOSE A pilot study of high dose coenzyme Q(10 ) ( CoQ(10))/vitamin E therapy in Friedreich 's ataxia ( FRDA ) patients result ed in significant clinical improvements in most patients . This study investigated the potential for this treatment to modify clinical progression in FRDA in a r and omized double blind trial . METHODS Fifty FRDA patients were r and omly divided into high or low dose CoQ(10)/ vitamin E groups . The change in International Co-operative Ataxia Ratings Scale ( ICARS ) was assessed over 2 years as the primary end-point . A post hoc analysis was made using cross-sectional data . RESULTS At baseline serum CoQ(10 ) and vitamin E levels were significantly decreased in the FRDA patients ( P < 0.001 ) . During the trial CoQ(10 ) and vitamin E levels significantly increased in both groups ( P < 0.01 ) . The primary and secondary end-points were not significantly different between the therapy groups . When compared to cross-sectional data 49 % of all patients demonstrated improved ICARS scores . This responder group had significantly lower baseline serum CoQ(10 ) levels . CONCLUSIONS A high proportion of FRDA patients have a decreased serum CoQ(10 ) level which was the best predictor of a positive clinical response to CoQ(10)/vitamin E therapy . Low and high dose CoQ(10)/vitamin E therapies were equally effective in improving ICARS scores Background : Friedreich ’s ataxia ( FRDA ) , the most common genetic cause of ataxia , is characterised by progressive neurodegeneration and cardiomyopathy . Initial treatments are likely to slow progression rather than reverse morbidity . An appropriate and sensitive scale to measure disease progress is critical to detect the benefit of treatments . Objective : To compare the  Friedreich Ataxia Rating Scale ( FARS )  with other scales proposed as outcome measures for FRDA . Methods : 76 participants were assessed with the  FARS  and the  International Cooperative Ataxia Rating Scale ( ICARS )  and 72 of these participants were also assessed with the  Functional Independence Measure  and the  Modified Barthel Index .  43 participants had repeat measures at an interval of 12 months . Sensitivity and responsiveness were assessed using the effect size for each measure and the sample size required for a placebo-controlled clinical trial . Results : The FARS showed a high correlation with the other three measures . A significant change in the score over 12 months was detected by the FARS , the International Cooperative Ataxia Rating Scale and the Functional Independence Measure . The FARS had the greatest effect size and requires fewer patients for an equivalently powered study . Conclusions : Of the scales assessed , the FARS is the best to use in clinical trials of FRDA . This is based on effect size , and power calculations that show that fewer participants are required to demonstrate the same effect of an intervention . Further work is required to develop more sensitive and responsive instruments Objective : To examine the potential validity of performance measures and examination-based scales in Friedreich ataxia ( FA ) by examining their correlation with disease characteristics . Methods : The authors assessed the properties of a c and i date clinical outcome measure , the  Friedreich Ataxia Rating Scale ( FARS )  , and simple performance measures ( 9-hole peg test , the timed 25-foot walk , PATA test , and low-contrast letter acuity )  in 155 patients with FA from six institutions , and correlated the scores with disease duration , functional disability , activity of daily living scores , age , and shorter GAA repeat length to assess whether these measures capture the severity of neurologic dysfunction in FA . Results : Scores for the FARS and performance measures correlated significantly with functional disability , activities of daily living scores , and disease duration , showing that these measures meet essential criteria for construct validity for measuring the progressive nature of FA . In addition , the FARS and transformed performance measures scores were predicted by age and shorter GAA repeat length in linear regression models accounting for sex and testing site . Correlations between performance measures were moderate in magnitude , suggesting that each test captures separate yet related dimensions of neurologic function in FA and that a composite measure might better predict disease status . Composite measures created using cohort means and st and ard deviations predicted disease status better than or equal to single performance measures or examination-based measures . Conclusions : The Friedreich Ataxia Rating Scale , performance measures , and performance measure composites provide valid assessment s of disease progression in Friedreich ataxia Genetic disorders of iron metabolism and chronic inflammation often evoke local iron accumulation . In Friedreich ataxia , decreased iron-sulphur cluster and heme formation leads to mitochondrial iron accumulation and ensuing oxidative damage that primarily affects sensory neurons , the myocardium , and endocrine gl and s. We assessed the possibility of reducing brain iron accumulation in Friedreich ataxia patients with a membrane-permeant chelator capable of shuttling chelated iron from cells to transferrin , using regimens suitable for patients with no systemic iron overload . Brain magnetic resonance imaging ( MRI ) of Friedreich ataxia patients compared with age-matched controls revealed smaller and irregularly shaped dentate nuclei with significantly ( P < .027 ) higher H-relaxation rates R2 * , indicating regional iron accumulation . A 6-month treatment with 20 to 30 mg/kg/d deferiprone of 9 adolescent patients with no overt cardiomyopathy  reduced R2 * from 18.3 s(-1 ) ( + /- 1.6 s(-1 ) ) to 15.7 s(-1 ) ( + /- 0.7 s(-1 ) ; P < .002 ) , specifically in dentate nuclei and proportionally to the initial R2 * ( r = 0.90 ) . Chelator treatment caused no apparent hematologic or neurologic side effects while reducing neuropathy and ataxic gait in the youngest patients . To our knowledge , this is the first clinical demonstration of chelation removing labile iron accumulated in a specific brain area implicated in a neurodegenerative disease . The use of moderate chelation for relocating iron from areas of deposition to areas of deprivation has clinical implication s for various neurodegenerative and hematologic disorders BACKGROUND Decreased mitochondrial respiratory chain function and increased oxidative stress have been implicated in the pathogenesis of Friedreich ataxia ( FRDA ) , raising the possibility that energy enhancement and antioxidant therapies may be an effective treatment . OBJECTIVE To evaluate the long-term efficacy of a combined antioxidant and mitochondrial enhancement therapy on the bioenergetics and clinical course of FRDA . DESIGN Open-labeled pilot trial over 47 months . Patients Seventy-seven patients with clinical and genetically defined FRDA . Intervention A combined coenzyme Q(10 ) ( 400 mg/d ) and vitamin E ( 2100 IU/d ) therapy of 10 patients with FRDA over 47 months . MAIN OUTCOME MEASURES Clinical assessment using echocardiography and the International Cooperative Ataxia Rating Scale and cardiac and skeletal muscle bioenergetics as assessed using phosphorus P 31 magnetic resonance spectroscopy . RESULTS There was a significant improvement in cardiac and skeletal muscle bioenergetics that was maintained throughout the 47 months of therapy . Echocardiographic data revealed significantly increased fractional shortening at the 35- and 47-month time points . Comparison with cross-sectional data from 77 patients with FRDA indicated the changes in total International Cooperative Ataxia Rating Scale and kinetic scores over the trial period were better than predicted for 7 patients , but the posture and gait and h and dexterity scores progressed as predicted . CONCLUSION This therapy result ed in sustained improvement in mitochondrial energy synthesis that was associated with a slowing of the progression of certain clinical features and a significant improvement in cardiac function OBJECTIVE To assess the efficacy of idebenone on neurological function in patients with Friedreich ataxia . DESIGN R and omized , double-blind , placebo-controlled intervention trial . SETTING Children 's Hospital of Philadelphia and the University of California at Los Angeles . PARTICIPANTS Seventy ambulatory pediatric patients ( age , 8 - 18 years ) with a baseline International Cooperative Ataxia Rating Scale ( ICARS ) score of 10 to 54 . INTERVENTIONS Participants were r and omized into 1 of 3 treatment arms : 450 or 900 mg of idebenone per day ( in those with a body weight < or = or > 45 kg , respectively ; n = 22 ) ; 1350 or 2250 mg of idebenone per day ( n = 24 ) ; or placebo ( n = 24 ) . MAIN OUTCOME MEASURES Mean change from baseline to week 24 in ICARS score was the primary efficacy variable . Mean change in Friedreich Ataxia Rating Scale ( FARS ) score , performance measures , and activities of daily living were the secondary efficacy variables . RESULTS Patients who received idebenone improved by 2.5 points on mean ICARS score compared with baseline , while patients in the placebo group improved by 1.3 points . Patients who took idebenone also improved by 1.6 points on the FARS , while patients taking placebo declined by 0.6 points . For both end points , the difference between the idebenone and placebo groups was not statistically different . CONCLUSIONS Idebenone did not significantly alter neurological function in Friedreich ataxia during the 6-month study . Larger studies of longer duration may be needed to assess the therapeutic potential of drug c and i date s on neurological function in Friedreich ataxia . Trial Registration clinical trials.gov Identifier : NCT00537680 Fast breath-hold cardiovascular magnetic resonance ( CMR ) shows excellent results for inter study reproducibility of left ventricular ( LV ) volumes , ejection fraction , and mass , which are thought to be superior to results of 2-dimensional echocardiography . However , there is no direct comparison of the inter study reproducibility of both methods in the same subjects . A total of 60 subjects ( normal volunteers [ n = 20 ] , or patients with heart failure [ n = 20 ] or LV hypertrophy [ n = 20 ] ) underwent 2 CMRs and 2 echocardiographic studies for assessment of LV volumes , function , and mass . The inter study reproducibility coefficient of variability was superior for CMR in all groups for all parameters . Statistical significance was reached for end-systolic volume ( 4.4 % to 9.2 % vs 13.7 % to 20.3 % , p < 0.001 ) , ejection fraction ( 2.4 % to 7.3 % vs 8.6 % to 19.4 % , p < 0.001 ) , and mass ( 2.8 % to 4.8 % vs 11.6 % to 15.7 % p < 0.001 ) , with a trend for end-diastolic volume ( 2.9 % to 4.9 % vs 5.5 % to 10.5 % , p = 0.17 ) . The superior inter study reproducibility result ed in considerably lower calculated sample sizes ( reductions of 55 % to 93 % ) required by CMR compared with echocardiography to show clinical ly relevant changes in LV dimensions and function . Thus , CMR has excellent inter study reproducibility in normal , dilated , and hypertrophic hearts , and is superior to 2-dimensional echocardiography BACKGROUND Antioxidant therapy is a new therapeutical approach for patients with Friedreich ataxia . AIMS To assess the effectiveness of long-term idebenone treatment in Friedreich ataxia patients . METHODS An open-labelled prospect i ve study . Ten paediatric patients ( age range 8 - 18 years ) and 14 adults ( age range 18 - 46 years ) with genetic diagnosis of Friedreich ataxia were treated with idebenone ( 5 - 20mg/kg/day ) for 3 - 5 years . Neurological evolution was evaluated using the International Cooperative Ataxia Rating Scale ( ICARS ) , and cardiological outcomes using echocardiography . RESULTS In paediatric patients , no significant differences were observed in ICARS scores and echocardiographic measurements when comparing baseline status and after 5 years of follow-up . Concerning adult cases , ICARS scores showed a significant increase in neurological dysfunctions during 3 years of therapy ( Wilcoxon test , p=0.005 ) , while echocardiographic measurements remained unchanged . CONCLUSIONS Our results indicate that longer-term idebenone treatment prevented progression of cardiomyopathy in both paediatric and adult patients , whereas its stabilizing effect on neurological dysfunction was present only in the paediatric population , mainly before puberty . This suggests that the age at which idebenone treatment is initiated may be an important factor in the effectiveness of the therapy To determine the role of recombinant human erythropoietin as a possible treatment option in Friedreich 's ataxia , we performed an open‐label clinical pilot study . Primary outcome measure was the change of frataxin levels at week 8 versus baseline . Twelve Friedreich 's ataxia patients received 5,000 units recombinant human erythropoietin three times weekly subcutaneously . Frataxin levels were measured in isolated lymphocytes by enzyme‐linked immunosorbent assay . In addition , urinary 8‐hydroxydeoxyguanosine and serum peroxides , were measured . Treatment with recombinant human erythropoietin showed a persistent and significant increase in frataxin levels after 8 weeks ( p < 0.01 ) . All patients showed a reduction of oxid 
    Output:
    
No RCT using idebenone or any other pharmacological treatment has shown significant benefit on neurological symptoms associated with Friedreich ataxia .