The different functions of the BPB (as a stimulator, biopotential signal sensor, goniometry sensor, pressure or temperature sensor) and the availability of multiple BPBs in one patient (up to 850 BPBs) gives the clinician many opportunities to restore neurological function, especially in poststroke syndrome, spinal cord injury, cerebral palsy, multiple sclerosis, traumatic brain injury, and for limb sensing in amputees to control fitted prostheses.

Take, for example, the case where a paralyzed upper extremity is implanted with multiple BPBs placed near motor-points or nerves of muscles in the arm, forearm, and hand. It will be possible to trigger sequential functional muscle actions to extend the arm and forearm, and open the hand to grasp an object. The limits of each functional action can be controlled from implanted BPBs working as goniometry sensors, measuring the angles of the elbow (see Figure 18.9) and wrist, and implanted BPBs working as pressure sensors, measuring the pressure at the finger tip (Figure 18.13).

The reverse of this extension can be similarly achieved using this stimulating and sensing system to bring the grasped object, for example, to the mouth. Similar closed-loop controls of stimulation could be used in the lower extremities for standing and ambulation. For partially paralyzed extremities, sensing of the muscle activities using BPBs would act as triggers to other BPBs to stimulate the motor-points of these muscles, thus augmenting the total action. Goniometry sensors would add the closed-loop controls to reduce or stop the actions. This approach could be used to augment swallowing, bladder control, and respiration.

Where pressure points need to be monitored — for example, at the heel (as a trigger for improving walking in stroke patients), the buttock (to avoid pressure sores), or hand (to detect the grasping of an

FIGURE 18.14 (See color insert following page 15-4). Use of BPBs in amputee patients.

object) — BPB devices placed in these sites can measure the pressure and either trigger motor-point functional stimulation to activate muscles, or stop a functional stimulation sequence.

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