Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a disorder marked by loss of motoneurons. We hypothesized that subjects with ALS would have an altered gait rhythm, with an increase in both the magnitude of the stride-to-stride fluctuations and perturbations in the fluctuation dynamics. To test for this locomotor instability, we quantitatively compared the gait rhythm of subjects with ALS with that of normal controls and with that of subjects with Parkinson's disease (PD) and Huntington's disease (HD), pathologies of the basal ganglia. Subjects walked for 5 min at their usual pace wearing an ankle-worn recorder that enabled determination of the duration of each stride and of stride-to-stride fluctuations. We found that the gait of patients with ALS is less steady and more temporally disorganized compared with that of healthy controls. In addition, advanced ALS, HD, and PD were associated with certain common, as well as apparently distinct, features of altered stride dynamics. Thus stride-to-stride control of gait rhythm is apparently compromised with ALS. Moreover, a matrix of markers based on gait dynamics may be useful in characterizing certain pathologies of motor control and, possibly, in quantitatively monitoring disease progression and evaluating therapeutic interventions.

Gait dynamics, fractals and falls: Finding meaning in the stride-to-stride fluctuations of human walking

“…Application of other analysis methods allows one to capture other features of gait time series and generate an array or matrix of outcome measures, each evaluating different aspects of the dynamics. Studies in neurodegenerative disease support the idea that such a matrix of dynamical measures may be helpful in more fully characterizing different pathologic states (Hausdorff, Cudkowicz, Firtion, Wei, & Goldberger, 1998;Hausdorff et al, 2000.…”

“…In support of this idea, a recent study demonstrated that a pair of measures of gait dynamics that characterize the stride-tostride fluctuations can be used to distinguish among different neurodegenerative diseases (Carletti, Fanelli, & Guarino, 2006). In other words, by generating a matrix of parameters that reflect different features of gait dynamics, we may be able to improve our ability to evaluate gait dynamics and instability and its response to different therapeutic interventions (Hausdorff et al, 2000).…”

“…Patients with mild Lou Gehrig's disease (amyotrophic lateral sclerosis, ALS) had an apparently normal gait pattern, but significant changes in a non-stationary index of the stride-to-stride fluctuations (p < .04), compared to healthy controls. Perhaps equally important, among participants with ALS, Parkinson's disease, and Huntington's disease, certain changes in gait dynamics appear to be common to neurological impairment while others are apparently disease specific (Hausdorff et al, 2000). For example, while an increased stride time variability appears to be common in all three groups, to varying degrees, changes in the fractal properties and other dynamic properties appear to be more sensitive to specific diseases.…”

“…A reduced average stride length plays an important role in the gait disturbance of PD, however, another critical feature characteristic of PD is a loss of consistency and a decline in the ability to produce a steady gait rhythm. Patients with PD walk with increased stride-to-stride variability and have a decreased fractal scaling index (Blin, Ferrandez, & Serratrice, 1990;Frenkel-Toledo et al, 2005b;Hausdorff et al, 1998;Hausdorff, Peng et al, 1995;Hausdorff et al, 2000). Increased stride-to-stride variability, both in the stride length and stride time, has been observed in advanced PD (Blin et al, 1990;Hausdorff et al, 1998;Stolze et al, 2001) as well as in patients early in the disease process who have not even begun to take anti-parkinsonian medications (Baltadjieva, Giladi, Gruendlinger, Peretz, & Hausdorff, 2006;Hausdorff, Peng et al, 1995).…”

“…Gait disturbances and falls are one of the most significant motor complaints in PD and a leading cause of loss of independence and institutionalization (Ashburn, Stack, Pickering, & Ward, 2001;Bloem, Hausdorff, Visser, & Giladi, 2004;Hausdorff et al, 2000). As discussed above, gait variability apparently predicts falls in older adults with 'idiopathic falls' as well as in patients with Alzheimer's disease (Azizah, Lajoie, & Teasdale, 2003;Hausdorff, Edelberg et al, 1997;Hausdorff, Rios et al, 2001;Maki, 1997;Nakamura, Meguro, & Sasaki, 1996;Visser, 1983;).…”