Biomedical Engineering Reference
In-Depth Information
10.3.2.3 TNMES
Therapeutic neuromuscular electrical stimulation (TNMES) of the wrist and finger
extensors is a therapy in which muscles are stimulated without voluntary muscle
contraction. TNMES makes use of the key element intensity in therapy. An
increase of muscle force of the stimulated muscles is mentioned in some studies as
a beneficial effect of TNMES. However, it is not known whether improvements on
arm and hand function are clinically relevant or whether functional improvements
can be achieved (De Kroon 2002).
10.4 ROBOTIC DEVICES
To enhance motor relearning during rehabilitation therapy, integration of the
previously mentioned key elements is essential. Unfortunately in current clin-
ical practice this is labor-intensive and requires one-to-one manual interactions
with therapists, which poses a high strain on therapists (Volpe 2002). With the
upcoming technologies of robotic devices and augmented feedback it is possible
to provide a combination of intense, task-specific, and interactive therapy in a
motivating environment. With robotic devices, patients may therefore achieve
increased gains from rehabilitation treatment (Feys 1998, Kwakkel 1999).
10.4.1 Passive and Active Movement
Robotic devices can be used in rehabilitation therapy for passive, active-assisted
and active-resisted movement training. The training modality depends on the
amount of assisting force provided by the robot; total assistance for passive
movements, no assistance for active movements, and force against the movement
direction for active-resisted.
Studies reporting the design and development of robotic devices have been
reported extensively. However, only a few studies examine the effect of robotic
devices on stroke rehabilitation in a clinical setting. Overall, robot-aided therapy
on the upper extremity in stroke survivors seems to improve both short and long-
term motor functions, but functional improvements are rarely seen. These studies
mainly focused on the proximal arm, while proper control of both arm and hand
are pre-requisites for many activities of daily living (Prange 2006, Kwakkel 2008).
10.4.2 Gravity Compensation
Most robotic devices use one of the modalities of training, passive, active-assisted,
or active-resisted, in combination with gravity compensation. Until recently it was
unknown what the effect of solely gravity compensation is on the arm and hand
function of stroke survivors. A device providing solely gravity compensation is the
Freebal (Stienen 2007), see
Figure 10.1
.
Research to the effect of providing gravity
compensation has shown an instantaneously increase of the range of motion of the
