A general framework for automatic closed-loop control of bladder voiding induced by intraspinal microstimulation in rats

Individuals with spinal cord injury or neurological disorders have problems in voiding function due to the dyssynergic contraction of the urethral sphincter. Here, we introduce a closed-loop control of intraspinal microstimulation (ISMS) for efficient bladder voiding. The strategy is based on asynchronous two-electrode ISMS with combined pulse-amplitude and pulse-frequency modulation without requiring rhizotomy, neurotomy, or high-frequency blocking. Intermittent stimulation is alternately applied to the two electrodes that are implanted in the S2 lateral ventral horn and S1 dorsal gray commissure, to excite the bladder motoneurons and to inhibit the urethral sphincter motoneurons. Asynchronous stimulation would lead to reduce the net electric field and to maximize the selective stimulation. The proposed closed-loop system attains a highly voiding efficiency of 77.2-100%, with an average of 91.28 +/- 8.4%. This work represents a promising approach to the development of a natural and robust motor neuroprosthesis device for restoring bladder functions.

Automated summary

The study introduces a closed-loop control of intraspinal microstimulation (ISMS) for efficient bladder voiding, utilizing asynchronous two-electrode stimulation to activate bladder motoneurons and inhibit urethral sphincter motoneurons. This approach achieves high voiding efficiency and presents a promising method for restoring bladder functions with a natural and robust motor neuroprosthesis device.