Hypothesis: Friedreich’s ataxia (FA) is an inherited disease characterized by progressive motor weakness, sensory loss, balance deficits, and an ataxic gait pattern. Increased gait variability is a common feature of ataxia and is related to balance deficits and falls risk in people with cerebellar disorders. Earlier age at FA onset has been shown to be predictive of wheelchair use and loss of ambulation. The relationship between disease duration, balance deficits and gait variability has not been investigated in adults with FA. We hypothesize that longer disease duration and increased balance deficits are related to increased gait variability in adults with FA.
Subjects: Eight adults with genetically confirmed FA (29.4 ± 9.0 years) and average disease duration 9.9 ± 3.8 years
Materials/Methods: This research represents a component of a longitudinal study which examined balance, gait and neurological status in adults with FA. Gait variability, specifically step and stride length variability, was measured at comfortable and fast walking speeds using the GAITRite Walkway System. Balance was assessed using the Berg Balance Scale (BBS) and the Biodex Balance System SD. Pearson’s product correlation coefficient was employed to assess the relationship between disease duration, quantitative balance parameters and gait variability; while Spearman’s rank correlation coefficient was used to assess the relationship between BBS scores, disease duration and gait variability.
Results: BBS scores were not associated with gait variability (p>0.05). Disease duration was positively correlated with step length variability during fast walking (p=0.047). The Biodex Postural Stability test overall stability indices with eyes closed were positively correlated with stride length variability during comfortable walking (p=0.006) and with step and stride length variability during fast walking (p=0.014 and p=0.004, respectively). The Biodex Limits of Stability test overall directional control scores were negatively associated with step length variability during fast walking (p=0.038). There were no other significant correlations between disease duration, balance variables and gait variability.
Conclusions: Greater gait variability was exhibited by adults with FA who had longer disease duration. Results demonstrated a strong association between postural stability indices, limits of stability scores and step and stride length variability, particularly during fast walking. This study is the first to demonstrate a relationship between disease duration, balance deficits and gait variability in adults with FA.
Clinical Relevance: Worsening balance deficits in adults with FA may contribute to increased gait variability, particularly in those with longer disease duration. Knowledge of the relationship among these variables may assist physical therapists to predict when adults with FA would benefit most from interventions to ameliorate impairments of balance and gait variability and predict future activity limitations in walking.
Available at: http://works.bepress.com/kelly_sullivan/180/