Handling of the patient.
Do we need machines to move
the limbs of our patients on the treadmill? Our current believe
is no, no, possibly in the future.
No, because all patients
trained thisway stop using their own voluntary activity during the
whole or part of the gait cycle. This violates one of the main principles
(see above): Use as much and as intensively as possible your remaining
activity and thereby enhance it. Activity related motor learning
will not happen with passive movements. Elegant animal experiments
are currently being performed by the Edgerton group in Los Angeles,
which show precisely that this prediction is correct.
No, because nothing can be better in
setting, tilting, dorsiflexing etc a limb and can react immediately
if the gait does not develop properly than a skilled therapist.
An impractical number of sensors on each joint would be needed to
report - very fast - the emerging movement, the computing device
calculate the deviation and several motors correct the movement
via a feedback loop. The active component contributed or anticipated
by the patient (which might then be pre-settable) needs to be worked
in.
Possibly in the future: Interesting features might evolve
from such presetting (see above), if they allow the patient to realize
his achieved or expected active contribution. Thisway a feedback
type of setting is created, which when properly set, demands active
movement by the patient which can be graded according to the patients
momentary conditions or the state of the training schedule.
Most recent models of the Locomat (Colombo
ETH Zürich, 2005) include some feedback features. However,
when we recently (Jan. 2005) tested the device together with a mid
thoracic completely paralyzed girl which had been using it for a
few weeks, we realized that she had learned to trick the robot:
By using her latissimus dorsi muscles she moved her pelvis enough
for the machine to assume active hip flexion. And it had taken a
considerable amount of time to mount the robot, too much for everyday
use. One argument pro robot we often heard (and might in fact be
a major reason why it was purchased by some rehab institutions)
is that "patients like it". An unusual level of decision
making indeed, if it is not accompanied by superior progress in
walking capability (which there is no published evidence for up
till today, July 2005). The Step Trainer introduced by Hesse
has a similar problem: While during stance phase active work by
the patient is demanded, swing phase happens passively lest the
patient is continually reminded to actively contribute.
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