Neuro-degenerative disease often affects gait and mobility. To understand better the pathophysiology of these diseases and to improve our ability to measure responses to therapeutic interventions, it may be helpful to quantify gait dynamics accurately. The records in this database are from patients with Parkinson's disease (n = 15), Huntington's disease (n = 20), or amyotrophic lateral sclerosis (n = 13). Records from 16 healthy control subjects are also included here.
The raw data were obtained using force-sensitive resistors, with the output roughly proportional to the force under the foot. Stride-to-stride measures of footfall contact times were derived from these signals, as illustrated below. (Click here for a PostScript version of this figure.)
![[Examples of Gait Time Series]](example-ts.png)
Each of the 64 records is identified by the name of the subject group (hunt, park, als, or control) followed by an arbitrary ID number. The four files associated with each record have names beginning with the record name, and suffixes indicating the type and contents of the file:
| Suffix | Contents |
|---|---|
| .hea | Header (text) |
| .let | Left foot signal (binary) |
| .rit | Right foot signal (binary) |
| .ts | Derived time series (text) |
Within the time series (.ts) files, the contents are:
| Column | Contents |
|---|---|
| 1 | Elapsed Time (sec) |
| 2 | Left Stride Interval (sec) |
| 3 | Right Stride Interval (sec) |
| 4 | Left Swing Interval (sec) |
| 5 | Right Swing Interval (sec) |
| 6 | Left Swing Interval (% of stride) |
| 7 | Right Swing Interval (% of stride) |
| 8 | Left Stance Interval (sec) |
| 9 | Right Stance Interval (sec) |
| 10 | Left Stance Interval (% of stride) |
| 11 | Right Stance Interval (% of stride) |
| 12 | Double Support Interval (sec) |
| 13 | Double Support Interval (% of stride) |
Please note that these time series have not been filtered.
A separate file (subject-description.txt, a tab-delimited text file) includes clinical information for each subject, including age, gender, height, weight, walking speed, and a measure of disease severity or duration. For the subjects with Parkinson's disease, this is the Hohn and Yahr score (a higher score indicates more advanced disease). For the subjects with Huntington's disease, this is the total functional capacity measure (a lower score indicates more advanced functional impairment). For the subjects with amyotrophic lateral sclerosis, the number here is the time in months since the diagnosis of the disease. For the control subjects, an arbitrary 0 is used as a place holder.
Questions for study
We have done some initial analyses of these data sets. Much, however, is still unknown. For example: Are the dynamics of the sub-phases of the stride (e.g., stance and swing) identical to that of the stride itself? What is the effect of disease on gait asymmetry? Are stride dynamics nonlinear? Does this change with disease?
References
We have reported the association between disease and the dynamics of the stride time. For more information about our analyses of these data files, please see:
- Hausdorff JM, Lertratanakul A, Cudkowicz ME, Peterson AL, Kaliton D, Goldberger AL. Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis. J Applied Physiology; 88:2045-2053, 2000.
- Hausdorff JM, Mitchell SL, Firtion R, Peng CK, Cudkowicz ME, Wei JY, Goldberger AL. Altered fractal dynamics of gait: reduced stride-interval correlations with aging and Huntington's disease. J Applied Physiology; 82:262-269, 1997.
Address for correspondence: jhausdor@caregroup.harvard.edu