Are transcutaneous electrical nerve stimulation (TENS) and functional electrical stimulation (FES) curative treatments for wrist drop?

FES—Not TENS—Is the Evidence-Based Treatment for Wrist Drop, But Neither "Cures" the Condition

Functional electrical stimulation (FES) combined with intensive task-specific wrist extension exercises is the first-line therapy for severe wrist drop, while TENS should not be used because it delivers only sensory-level currents that do not produce the muscle contraction and proprioceptive feedback required for motor recovery. 1, 2

Why FES Works and TENS Does Not

FES actively contracts paralyzed or weak wrist extensor muscles by delivering motor-level currents that depolarize peripheral motor nerves, producing functional movements and proprioceptive feedback that promotes neural reorganization and motor learning. 1 In contrast, TENS delivers sensory-level currents designed to activate pain-inhibitory pathways without causing muscle contraction, making it fundamentally inappropriate for motor rehabilitation. 1, 3

The American Stroke Association explicitly recommends FES combined with active exercise rather than TENS or immobilization for severe wrist drop. 1, 2

Expected Outcomes: Improvement, Not Cure

FES produces measurable gains but does not "cure" wrist drop:

• Meta-analysis of randomized controlled trials demonstrates significant increases in wrist-extension muscle force (high-quality evidence). 2
• Short-term application leads to improved motor strength and motor control with measurable reduction in impairment severity (moderate evidence from multiple RCTs). 2
• However, evidence does NOT consistently show improvements in functional outcomes or activities of daily living—patients gain muscle force but may not translate this into meaningful hand function. 2, 4

FES Protocol for Wrist Drop

Timing and Duration

• Initiate FES within the first 6 months post-injury to align with the critical window for motor recovery. 1, 2, 4
• Apply surface electrodes to wrist and forearm extensor muscles for 30 minutes, three times daily, during active attempts at wrist extension. 1, 2
• FES is a time-limited intervention typically used during the first several weeks of rehabilitation, not a permanent solution. 1, 2, 4

Integration with Active Practice

• FES must be paired with intensive, progressive, task-oriented training; FES alone is insufficient for functional gains. 1, 2
• Start with supported wrist extension movements on a table surface, advancing to unsupported movements. 2
• Add structured resistance training starting at 40% of 1-repetition maximum with 10–15 repetitions, progressing to 41–60% intensity as tolerated. 2

Electrode Placement

• Position surface electrodes over the motor points of wrist extensor muscle groups. 1
• Modern FES devices monitor EMG or EEG signals and deliver stimulation only when the patient attempts the corresponding voluntary movement. 1

Critical Pitfalls to Avoid

Do Not Use TENS for Wrist Drop

• TENS has demonstrated only insignificant or very low levels of pain and functional improvement across diverse populations. 5
• While one pediatric study showed TENS combined with exercise improved handgrip strength in hemiplegic cerebral palsy, 6 this does not translate to adult wrist drop rehabilitation where motor-level stimulation is required.
• TENS is appropriate for pain management in neuropathic or musculoskeletal conditions, 3, 7 but not for motor rehabilitation.

Avoid Static Splinting

• Static splinting or immobilization of the wrist should be avoided because it promotes learned non-use, muscle deconditioning, compensatory accessory-muscle strategies, increased pain, and overall poorer functional recovery. 1, 2
• If a removable splint is deemed necessary for positioning, monitor closely and discontinue if pain or skin breakdown occurs. 1, 2

Do Not Confuse FES with Other Modalities

• Do not confuse percutaneous tibial nerve stimulation (PTNS) with FES—PTNS is used for pelvic floor disorders, not motor rehabilitation. 1
• Constraint-induced movement therapy (CIMT) is not recommended for severe wrist drop because it requires minimum baseline wrist extension of ≈20° and finger extension of ≈10°, which patients with severe wrist drop do not meet. 2

Evidence Strength and Nuances

The American Heart Association's 2010 comprehensive stroke rehabilitation statement noted conflicting evidence for upper extremity electrical stimulation, with a meta-analysis failing to find advantage over usual care for wrist and finger stimulation. 8 However, more recent guideline syntheses (2025–2026) from the American Stroke Association and VA/DoD clinical practice guidelines have clarified that FES has the strongest evidence for enhancing motor function in severe wrist drop when combined with active practice. 2, 4

For lower extremity applications, FES combined with biofeedback or physical therapy has shown superior results for foot drop, with benefits evident when the stimulator is used. 8, 4 Implantable nerve stimulators have demonstrated safety and effectiveness in reducing foot drop with improvements in gait speed and walking endurance. 8, 4

Bottom Line Algorithm

1. Confirm wrist drop etiology: Rule out peripheral radial nerve pathology with nerve conduction studies; consider rare central causes such as cerebral peduncle infarction. 9
2. If within 6 months of stroke or nerve injury: Initiate FES to wrist extensors, 30 minutes three times daily, during active extension attempts. 1, 2
3. Combine with intensive task practice: Progress from supported to unsupported movements with resistance training. 1, 2
4. Do not use TENS: It lacks motor-level stimulation and proprioceptive feedback. 1
5. Avoid static splinting: Use only if absolutely necessary for positioning, with close monitoring. 1, 2
6. Set realistic expectations: FES improves muscle force and motor control but does not consistently restore functional independence in activities of daily living. 2, 4