The Role of Verbal Fluency in the Cerebellar Cognitive Affective Syndrome Scale in Friedreich Ataxia.

Cerebellar pathology engenders the disturbance of movement that characterizes Friedreich ataxia (FRDA), yet the impact of cerebellar pathology on cognition in FRDA remains unclear. Numerous studies have unequivocally demonstrated the role of the cerebellar pathology in disturbed cognitive, language and affective regulation, referred to as Cerebellar Cognitive Affective Syndrome (CCAS), and quantified by the CCAS-Scale (CCAS-S). The presence of dysarthria in many individuals with ataxia, particularly FRDA, may confound results on some items of the CCAS-S resulting in false-positive scores. This study explored the relationship between performance on the CCAS-S and clinical metrics of disease severity in 57 adults with FRDA. In addition, this study explored the relationship between measures of intelligibility and naturalness of speech and scores on the CCAS-S in a subgroup of 39 individuals with FRDA. We demonstrated a significant relationship between clinical metrics and performance on the CCAS-S. In addition, we confirmed the items that returned the greatest rate of failure were based on Verbal Fluency Tasks, revealing a significant relationship between these items and measures of speech. Measures of speech explained over half of the variance in the CCAS-S score suggesting the role of dysarthria in the performance on the CCAS-S is not clear. Further work is required prior to adopting the CCAS-S as a cognitive screening tool for individuals with FRDA.

The Responsiveness of Gait and Balance Outcomes to Disease Progression in Friedreich Ataxia.

To identify gait and balance measures that are responsive to change during the timeline of a clinical trial in Friedreich ataxia (FRDA), we administered a battery of potential measures three times over a 12-month period. Sixty-one ambulant individuals with FRDA underwent assessment of gait and balance at baseline, 6 months and 12 months. Outcomes included GAITRite® spatiotemporal gait parameters; Biodex Balance System Postural Stability Test (PST) and Limits of Stability; Berg Balance Scale (BBS); Timed 25-Foot Walk Test; Dynamic Gait Index (DGI); SenseWear MF Armband step and energy activity; and the Friedreich Ataxia Rating Scale Upright Stability Subscale (FARS USS). The standardised response mean (SRM) or correlation coefficients were reported as effect size indices for comparison of internal responsiveness. Internal responsiveness was also analysed in subgroups. SenseWear Armband daily step count had the largest effect size of all the variables over 6 months (SRM = -0.615), while the PST medial-lateral index had the largest effect size (SRM = 0.829) over 12 months. The FARS USS (SRM = 0.824) and BBS (SRM = -0.720) were the only outcomes able to detect change over 12 months in all subgroups. The DGI was the most responsive outcome in children, detecting a mean change of -2.59 (95% CI -3.52 to -1.66, p < 0.001, SRM = -1.429). In conclusion, the FARS USS and BBS are highly responsive and can detect change in a wide range of ambulant individuals with FRDA. However, therapeutic effects in children may be best measured by the DGI.

Can rehabilitation improve the health and well-being in Friedreich's ataxia: a randomized controlled trial?

OBJECTIVE: To determine the effectiveness of a six-week rehabilitation programme followed by a home exercise programme for Friedreich's ataxia. DESIGN: Randomized, delayed-start control single-blind trial. SETTING: Outpatient rehabilitation centre. SUBJECTS: Ambulant or non-ambulant individuals with Friedreich's ataxia. INTERVENTION: Participants were randomized to a six-week outpatient rehabilitation programme, immediately (intervention group) or after a six-week delayed-start (control group). The rehabilitation was followed by a six-week home exercise programme. MAIN MEASURES: The primary outcome was the Functional Independence Measure. Other measures included the Friedreich Ataxia Impact Scale and the Friedreich Ataxia Rating Scale. Outcomes were administered at baseline, 6, 12 and 18 weeks. RESULTS: Of 159 individuals screened, 92 were excluded and 48 declined to participate. A total of 19 participants were enrolled in the study. There was no significant difference in Functional Independence Measure change from baseline to six weeks in the intervention group (mean ± standard deviation, 2.00 ± 3.16) as compared to the control group (0.56 ± 4.06). Change in the Friedreich Ataxia Impact Scale body movement subscale indicated a significant improvement in health and well-being in the intervention group compared to the control group ( P = 0.003). Significant within-group improvements in the Friedreich Ataxia Impact Scale and the motor domain of the Functional Independence Measure post-rehabilitation were not sustained post-home exercise programme. CONCLUSION: Our study indicates that rehabilitation can improve health and well-being in individuals with Friedreich's ataxia; however, a larger study is required to have sufficient power to detect a significant change in the most sensitive measure of function, the motor domain of the Functional Independence Measure.

Progress in the treatment of Friedreich ataxia.

Friedreich ataxia (FRDA) is a progressive neurological disorder affecting approximately 1 in 29,000 individuals of European descent. At present, there is no approved pharmacological treatment for this condition however research into treatment of FRDA has advanced considerably over the last two decades since the genetic cause was identified. Current proposed treatment strategies include decreasing oxidative stress, increasing cellular frataxin, improving mitochondrial function as well as modulating frataxin controlled metabolic pathways. Genetic and cell based therapies also hold great promise. Finally, physical therapies are being explored as a means of maximising function in those affected by FRDA.

Compound heterozygous FXN mutations and clinical outcome in friedreich ataxia.

OBJECTIVE: Friedreich ataxia (FRDA) is an inherited neurodegenerative disease characterized by ataxia and cardiomyopathy. Homozygous GAA trinucleotide repeat expansions in the first intron of FXN occur in 96% of affected individuals and reduce frataxin expression. Remaining individuals are compound heterozygous for a GAA expansion and a FXN point/insertion/deletion mutation. We examined disease-causing mutations and the impact on frataxin structure/function and clinical outcome in FRDA. METHODS: We compared clinical information from 111 compound heterozygotes and 131 individuals with homozygous expansions. Frataxin mutations were examined using structural modeling, stability analyses and systematic literature review, and categorized into four groups: (1) homozygous expansions, and three compound heterozygote groups; (2) null (no frataxin produced); (3) moderate/strong impact; and (4) minimal impact. Mean age of onset and the presence of cardiomyopathy and diabetes mellitus were compared using regression analyses. RESULTS: Mutations in the hydrophobic core of frataxin affected stability whereas surface residue mutations affected interactions with iron sulfur cluster assembly and heme biosynthetic proteins. The null group of compound heterozygotes had significantly earlier age of onset and increased diabetes mellitus, compared to the homozygous expansion group. There were no significant differences in mean age of onset between homozygotes and the minimal and moderate/strong impact groups. INTERPRETATION: In compound heterozygotes, expression of partially functional mutant frataxin delays age of onset and reduces diabetes mellitus, compared to those with no frataxin expression from the non-expanded allele. This integrated analysis of categorized frataxin mutations and their correlation with clinical outcome provide a definitive resource for investigating disease pathogenesis in FRDA.

Deferiprone in Friedreich ataxia: a 6-month randomized controlled trial.

OBJECTIVE: We conducted a 6-month, randomized, double-blind, placebo-controlled study to assess safety, tolerability, and efficacy of deferiprone in Friedreich ataxia (FRDA). METHODS: Seventy-two patients were treated with deferiprone 20, 40, or 60mg/kg/day or placebo, divided into 2 daily doses. Safety was the primary objective; secondary objectives included standardized neurological assessments (Friedreich Ataxia Rating Scale [FARS], International Cooperative Ataxia Rating Scale [ICARS], 9-Hole Peg Test [9HPT], Timed 25-Foot Walk, Low-Contrast Letter Acuity), general functional status (Activities of Daily Living), and cardiac assessments. RESULTS: Deferiprone was well tolerated at 20mg/kg/day, whereas more adverse events occurred in the 40mg/kg/day than in the placebo group. The 60mg/kg/day dose was discontinued due to worsening of ataxia in 2 patients. One patient on deferiprone 20mg/kg/day experienced reversible neutropenia, but none developed agranulocytosis. Deferiprone-treated patients receiving 20 or 40mg/kg/day showed a decline in the left ventricular mass index, compared to an increase in the placebo-treated patients. Patients receiving 20mg/kg/day of deferiprone had no significant change in FARS, similar to the placebo-treated patients, whereas those receiving 40mg/kg/day had worsening in FARS and ICARS scores. The lack of deterioration in the placebo arm impaired the ability to detect any potential protective effect of deferiprone. However, subgroup analyses in patients with less severe disease suggested a benefit of deferiprone 20mg/kg/day on ICARS, FARS, kinetic function, and 9HPT. INTERPRETATION: This study demonstrated an acceptable safety profile of deferiprone at 20mg/kg/day for the treatment of patients with FRDA. Subgroup analyses raise the possibility that, in patients with less severe disease, deferiprone 20mg/kg/day may reduce disease progression, whereas higher doses appear to worsen ataxia.

A study of up to 12 years of follow-up of Friedreich ataxia utilising four measurement tools.

OBJECTIVE: To explore the progression of Friedreich ataxia by analysing the change in scores of four clinical measures (the Friedreich Ataxia Rating Scale (FARS), the International Cooperative Ataxia Rating Scale (ICARS), the Functional Independence Measure (FIM) and the Modified Barthel Index (MBI)) over a period of up to 12 years, to ascertain the effects of clinical variables on performance of these measures, and to determine the most sensitive rating scale for measuring disease progression. METHODS: We measured the disease progression of up to 147 individuals against disease duration grouped into 5-year intervals. Additional subgroups were created to study the effects of the size of the smaller FXN intron 1 GAA repeat size (GAA1) and onset age on rating scale performance. RESULTS: Both the FARS and ICARS demonstrated greater change in the first 20 years post disease onset than in the subsequent 20 years during which there was little change in the mean score. While the FIM and MBI continued to deteriorate beyond 20 years post disease onset, floor effects were noted. As measured by the FARS, individuals with a larger GAA1 repeat were found to progress more quickly in the first 20 years of disease. CONCLUSIONS: Individuals with larger GAA1 repeat sizes and earlier ages of disease onset were shown to deteriorate at a faster rate and were associated with greater FARS and ICARS scores and lower FIM and MBI scores, which are indicative of greater disease severity.

HFE p.C282Y heterozygosity is associated with earlier disease onset in Friedreich ataxia.

BACKGROUND: Friedreich ataxia (FRDA) generally results from reduced frataxin, a mitochondrial protein involved in iron metabolism. We assessed whether HFE p.C282Y and/or p.H63D heterozygosity modifies age at disease onset or disease severity in individuals with FRDA. METHODS: One hundred seventy individuals with FRDA were assessed for the association of HFE p.C282Y and p.H63D with (1) age at disease onset and (2) Friedreich Ataxia Rating Scale (FARS) score. RESULTS: After adjusting for the smaller FXN GAA repeat size and sex, individuals with FRDA and heterozygous for p.C282Y had disease onset on average 3.72 years earlier than those homozygous for the wild-type amino acid (P = 0.02). Neither mutation affected disease severity as measured by FARS. CONCLUSIONS: It is hypothesized that the association between p.C282Y heterozygosity and an earlier age at FRDA onset relates to exacerbation of the already dysregulated iron metabolism that plays a major role in the pathogenesis of FRDA.

FXN methylation predicts expression and clinical outcome in Friedreich ataxia.

OBJECTIVE: Friedreich ataxia (FA) is the most common ataxia and results from an expanded GAA repeat in the first intron of FXN. This leads to epigenetic modifications and reduced frataxin. We investigated the relationships between genetic, epigenetic, and clinical parameters in a large case-control study of FA. METHODS: Clinical data and samples were obtained from individuals with FA during annual visits to our dedicated FA clinic. GAA expansions were evaluated by polymerase chain reaction (PCR) and restriction endonuclease digest. DNA methylation was measured using bisulfite-based EpiTYPER MassARRAY (Sequenom, San Diego, CA). FXN expression was determined using real-time reverse transcriptase PCR. Significant correlations between the different parameters were examined using the nonparametric Spearman rank correlation coefficient, as well as univariate and multivariate regression modeling. RESULTS: Characteristic DNA methylation was identified upstream and downstream of the expansion, and validated in an independent FA cohort. Univariate and multivariate analyses showed significant inverse correlations between upstream methylation and FXN expression, and variation in downstream methylation and age of onset. FXN expression also inversely correlated with the Friedreich Ataxia Rating Scale score, an indicator of disease severity. INTERPRETATION: These novel findings provide compelling evidence for the link between the GAA expansion, the DNA methylation profile, FXN expression, and clinical outcome in FA. Epigenetic profiling of FXN could be used to gain greater insight into disease onset and progression, but also as a biomarker to learn more about specific treatment responses and pharmacological mechanism(s). This work also highlights the potential for developing therapies aimed at increasing frataxin levels to treat this debilitating disease.

Harmonizing results of ataxia rating scales: mFARS, SARA, and ICARS.

The ever-increasing body of ataxia research provides opportunities for large-scale meta-analyses, systematic reviews, and data aggregation. Because multiple standardized scales are used to quantify ataxia severity, harmonization of these measures is necessary for quantitative data pooling. We applied the modified Friedreich Ataxia Rating Scale (mFARS), the Scale for the Assessment and Rating of Ataxia (SARA), and the International Cooperative Ataxia Rating Scale (ICARS) to a large cohort of people with Friedreich's ataxia. We provide regression coefficients for scale interconversion and discuss the reliability of this approach, together with insights into the differential sensitivities of mFARS and SARA to disease progression.

Determining the Validity of Conducting Rating Scales in Friedreich Ataxia through Video.

BACKGROUND: The Friedreich Ataxia Rating Scale (FARS) and the Scale for the Assessment and Rating of Ataxia (SARA) are commonly used neurological rating scales in Friedreich ataxia (FRDA). The modified Friedreich Ataxia Rating Scale (mFARS) has been accepted as an appropriate outcome measure for clinical trials in FRDA. OBJECTIVES: The COVID-19 pandemic has resulted in limited face-to-face interactions with individuals involved in natural history studies and clinical trials. The aim of this study was to determine the validity of conducting the mFARS and SARA through video. METHODS: Individuals who had the mFARS administered face-to-face in the previous 6 months were invited to participate. Participants were sent instructions and asked to have a carer present to assist. The mFARS and SARA were then administered by video. Differences between face-to-face and video scores and the reliability between scores obtained face-to-face and by video were examined. RESULTS: The mFARS and SARA were conducted by video with 19 individuals. Excellent test-retest reliability was seen in the mFARS lower limb coordination (ICC = 0.96, 95% CI 0.90-0.98) and upright stability sections (ICC = 0.97, 95% CI 0.93-0.99), total mFARS (ICC = 0.97, 95% CI 0.92-0.99) and SARA scores (ICC = 0.98, 95% CI 0.95-0.99). CONCLUSIONS: Excellent test-retest reliability was demonstrated in the majority of the mFARS sections, and in the total mFARS and SARA scores, suggesting that video is a valid method of conducting these scales. This method enables inclusion of participants who are unable to travel to study sites. A larger cohort will be required to further validate the use of video mFARS and SARA for future studies.

Probing the multifactorial source of hand dysfunction in Friedreich ataxia.

Friedreich ataxia (FRDA) has a significant effect on hand function which in turn, may compromise independence and quality of life. This study sought to identify the extent of muscle weakness, spasticity and changes in joint range in the hands of individuals with FRDA. We used the Modified Tardieu Scale (MTS), testing of muscle strength and goniometry to examine hand function in 19 individuals with FRDA. Relationships between clinical measures of disease severity, functional independence and measures of hand function were also explored. We found evidence for both upper and lower motor neuron impairment in this population. Thirteen (68.0%) participants had spasticity in the dominant wrist and finger flexors, and seven (36.8%) had contracture in at least one joint of either hand. Sixteen (84.3%) participants demonstrated weakness in the intrinsic musculature of the hands and the majority demonstrated some degree of hyperextension at the metacarpophalangeal joints of either hand. Significant correlations were found between functional independence capacity and clinical parameters, and components of spasticity and weakness in both the dominant and non-dominant hands. Moreover, spasticity and weakness in the dominant hand were shown to be significant predictors of reduced functional independence capacity. This study highlights for the first time the incidence of upper limb spasticity which, in combination with weakness and contracture, suggests a multifactorial source of hand dysfunction in people with FRDA.

How does performance of the Friedreich Ataxia Functional Composite compare to rating scales?

Progression of Friedreich ataxia (FRDA) is often measured using neurological rating scales such as the Friedreich Ataxia Rating Scale (FARS). Performance scales comprising functional measures have been used in other conditions due to their increased sensitivity and reproducibility and may replace examination-based measures. The aims of this study were to examine the relationship between the Friedreich Ataxia Functional Composite (FAFC) measures and characteristics of FRDA to determine if the FAFC is more sensitive to clinical change over time compared to its components. One hundred and twenty-two individuals completed the timed 25-foot walk (T25FW), 9-Hole Peg Test (9HPT) and the low-contrast letter acuity (LCLA) test at baseline, 63 at year 1, 34 at year 2 and 25 at year 3. Composite scores, Z2 (T25FW and 9HPT) and Z3 (T25FW, 9HPT and LCLA) were created. Correlation analyses were conducted. Change in FAFC components were examined over 1, 2, and 3 years. The FARS, Z2, Z3 and 9HPT showed significant change over all time points compared to baseline. The T25FW only demonstrated significant change over 3 years. The LCLA demonstrated no significant change over any of the time points. The FAFC shows significant change over time and indicates disease progression, however, this may result from individual components driving the differences. The LCLA showed no change over time, rendering Z3 redundant. The FAFC is of limited value in cohorts with non-ambulant individuals as it leads to skewing of the dataset and is better suited to less affected populations.

A longitudinal study of the Friedreich Ataxia Impact Scale.

BACKGROUND: Quality of life in Friedreich ataxia (FRDA) has been explored using various generic health status measurement tools, most commonly the Short Form Health Survey Version 2 (SF-36v2). The tool did not address many specific issues related to disease impact in people with FRDA. The Friedreich Ataxia Impact Scale (FAIS) was developed to examine clinically relevant areas in FRDA. The aims of the current study were to assess the relationship between the FAIS and clinical characteristics of FRDA, as well as to determine the responsiveness of the FAIS to change over one and two years. METHODS: One hundred and four individuals with FRDA, homozygous for the GAA expansion in intron 1 of FXN, completed the FAIS at baseline. Seventy individuals completed the FAIS again 12 months later and 49 completed the FAIS at 24 months. Clinical parameters and neurologic scales (Friedreich Ataxia Rating Scale (FARS)) were also recorded. RESULTS: The total FARS score, onset age and disease duration correlated significantly with FAIS subscales measuring symptoms and physical functioning. The physical and mental summary measures of the SF-36 V2 also correlated well with the FAIS subscales. Speech was the only subscale that demonstrated significant change over one and two years. CONCLUSIONS: The FAIS provides valuable insight into the perspective of individuals with FRDA on their health status, and is an important measure of morbidity. It has, however, limited responsiveness to change and its use in intervention studies is questionable.

An open-label trial in Friedreich ataxia suggests clinical benefit with high-dose resveratrol, without effect on frataxin levels.

Friedreich ataxia (FRDA) is due to a triplet repeat expansion in FXN, resulting in deficiency of the mitochondrial protein frataxin. Resveratrol is a naturally occurring polyphenol, identified to increase frataxin expression in cellular and mouse models of FRDA and has anti-oxidant properties. This open-label, non-randomized trial evaluated the effect of two different doses of resveratrol on peripheral blood mononuclear cell (PBMC) frataxin levels over a 12-week period in individuals with FRDA. Secondary outcome measures included PMBC FXN mRNA, oxidative stress markers, and clinical measures of disease severity. Safety and tolerability were studied. Twenty-four participants completed the study; 12 received low-dose resveratrol (1 g daily) and 12 high-dose resveratrol (5 g daily). PBMC frataxin levels did not change in either dosage group [low-dose group change: 0.08 pg/µg protein (95% CI -0.05, 0.21, p = 0.21); high-dose group change: 0.03 pg/µg protein (95% CI -0.10, 0.15, p = 0.62)]. Improvement in neurologic function was evident in the high-dose group [change in Friedreich Ataxia Rating Scale -3.4 points, 95% CI (-6.6, -0.3), p = 0.036], but not the low-dose group. Significant improvements in audiologic and speech measures, and in the oxidative stress marker plasma F2-isoprostane were demonstrated in the high-dose group only. There were no improvements in cardiac measures or patient-reported outcome measures. No serious adverse events were recorded. Gastrointestinal side-effects were a common, dose-related adverse event. This open-label study shows no effect of resveratrol on frataxin levels in FRDA, but suggests that independent positive clinical and biologic effects of high-dose resveratrol may exist. Further assessment of efficacy is warranted in a randomized placebo-controlled trial.

Increased prevalence of sleep-disordered breathing in Friedreich ataxia.

OBJECTIVES: We sought to document the prevalence and nature of sleep-disordered breathing (SDB) in individuals with Friedreich ataxia (FRDA) as well as establish the relationship, if any, between SDB and clinical parameters of FRDA. METHODS: Eighty-two individuals with FRDA were administered the Epworth Sleepiness Scale on an annual basis for up to 3 years. Individuals were referred for a sleep study if they had an Epworth Sleepiness Scale score >8 or had clinical symptoms suggestive of SDB. RESULTS: From this cohort, 21 individuals underwent a sleep study and 17 were diagnosed with obstructive sleep apnea syndrome, giving a minimum prevalence of 21%, which is greater than that found in the general population (3%-7%). Moreover, the presence of obstructive sleep apnea was significantly correlated with the duration of disease and clinical severity of FRDA. CONCLUSION: It is recommended that individuals with FRDA undergo regular screening for obstructive sleep apnea to identify the need for a sleep study and subsequent treatment if SDB is diagnosed.