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As mentioned previously, D.L.'s gait improvement was not as dramatic as T.R.'s. However, since T.R. lives in another state and was not available for the quantitative part of the study, only D.L.'s gait performance was analyzed at the Biomechanics Laboratory.
D.L. reported feeling generally looser in treatment conditions L (laser pointer) and V (VV Sport with display on) than in either condition N (no treatment) or G (VV Sport with display off).
The stride length and walking speed data are shown in Table 5.1. The uncertainty in the stride length is 5 millimeters; the time uncertainty of the foot strike data, used in the walking speed calculations, is 20 milliseconds.
| Condition | Length
1 |
(m)
2 |
Speed
1 |
(m/min)
2 |
Average Length (m) | Average Speed (m/min) |
|---|---|---|---|---|---|---|
| N | 1.214 | 1.179 | 75.9 | 73.7 | 1.197 | 74.8 |
| L | 1.267 | 1.332 | 76.0 | 79.9 | 1.300 | 78.0 |
| G | 1.123 | 1.234 | 62.4 | 66.1 | 1.124 | 64.3 |
| V | 1.284 | 1.268 | 71.3 | 76.1 | 1.276 | 73.7 |
Thus, the laser pointer provided an 8.2% improvement in average stride length over the control condition, for the trials analyzed. Stride length improvement of the VV Sport with the image on over the control average is more modest, at an average of 6.4%. Of course, the small size of the sample and the presence of the force plate cue force one to treat these data with caution.
Condition V, in which the image is displayed, represents a 13% increase in stride length over condition G, in which the image is not displayed. The relatively poor results for condition G compared to both V and the control (N) may reflect the effect of occluding part of the visual field. Another possibility is that a blank screen close to the eye is perceived as a wall, and that condition G is similar to an akinetic patient becoming ``stuck'' in a corner.
The walking speed data does not distinguish strongly between conditions N, L, and V. The relative slowness in condition G may be due to the reasons discussed in the preceding paragraph.
We also obtained data on the percentage of time spent in each of four
parts of the gait cycle for each leg (see Table 5.2)
. This data allows one
to look at the symmetry of the gait between the two legs. The four
parts of the gait cycle examined are heel descending, heel pressing
down on the ground, heel rising, and foot swinging forward. The data
are averaged over the two trials analyzed for each condition.
| Condition | Descending | Down | Rising | Swinging | |
|---|---|---|---|---|---|
| N | Affected
Unaffected |
4%
7% |
37%
41% |
23%
17% |
36%
35% |
| L | Affected
Unaffected |
4%
6% |
36%
36% |
22%
20% |
38%
38% |
| G | Affected
Unaffected |
7%
8% |
38%
38% |
20%
20% |
35%
34% |
| V | Affected
Unaffected |
7%
7% |
39%
41% |
17%
17% |
37%
35% |
The least symmetric gait is seen in condition N, as one would suspect. Conditions L and V provide an improvement over N, although given the sample size one can say no more than that the data are suggestive.
It is surprising that the most symmetric gait is provided by condition G. This may be related to the shorter stride length and lower walking speed for this condition.
Overlaying the graphs of knee angle versus time, with the initial affected heel strikes lined up, does not reveal any substantial difference in that gait parameter for the four conditions. While the L and V conditions arguably produced a better straightening of the knee than condition N, the same is not true when compared to condition G.
The other time-dependent data similarly failed to distinguish among the four treatment conditions.
As we achieved the best results in the second and fourth treatment conditions, there does not seem to have been a systematic learning effect across quantitative trials.