Stimulator

A stimulator is a device that delivers a stimulus to evoke a physiological or neural response. Stimulators may provide electrical, magnetic, optical, acoustic, or mechanical input and are used in medicine, neuroscience research, and industry. The term is often contrasted with stimulant, a substance that increases activity.

Medical electrical stimulators include implantable and external devices. Implantable examples are cardiac pacemakers and implantable cardioverter-defibrillators that deliver electrical pulses to regulate heart rhythm; deep brain stimulators and spinal cord stimulators that modulate neural circuits; cochlear implants that stimulate the auditory nerve; and peripheral nerve stimulators or functional electrical stimulation systems that activate muscles. External devices include transcutaneous electrical nerve stimulation (TENS) for pain relief, surface neuromuscular electrical stimulation (NMES), and other non-invasive stimulators used for therapy or rehabilitation.

Non-electrical stimulators include devices using magnetic fields for brain stimulation, such as transcranial magnetic stimulation (TMS), or weak direct currents in transcranial direct current stimulation (tDCS). Optical, acoustic, and mechanical stimulators are used in research, diagnostics, and industry and vary widely in mechanism and application.

Design and safety: Stimulators typically integrate a power source, electrodes or transducers, and a control or sensing unit. Many are regulated medical devices requiring risk management, clinical testing, and regulatory approval by authorities such as the FDA or EU medical device regulation. Considerations include biocompatibility, leakage currents, device interactions, battery life, and patient-specific anatomy. The field is advancing toward closed-loop systems that adjust stimulation based on feedback.