Functional Neurological Disorder (FND): How NEUBIE and Laser Therapy Can Help
What is FND?
Your scan came back clear. The letter said no damage. And yet your hand won't grip the way it used to, your leg gives out without warning, the tremor keeps its own timetable. That space between a normal scan and a body that won't cooperate is where Functional Neurological Disorder lives, and it is one of the conditions neurologists see most and explain worst.
The nervous system in FND is built normally. What has gone wrong is control. The brain has lost a reliable grip on how it sends and receives the signals that drive movement, so sound wiring gets used badly. The symptoms are real and often disabling: limb weakness, tremor, jerky movements, trouble walking, changes in sensation. Fatigue and muscle pain usually come with them. FND is not imagined, and you cannot will it away. It is a disorder of how the nervous system functions, and because the pathways themselves survive intact, there is room to get better.
How the NEUBIE can help
The NEUBIE sends a pulsed direct current (DC) signal while you move, with live biofeedback showing what your muscles are doing. In FND that external signal earns its place by giving the nervous system a clear, unfamiliar input to organise around. It pulls your attention off the symptom and back onto the movement, which is where FND tends to break down.
The waveform matters here. TENS and most muscle stimulators run on alternating current. The NEUBIE runs on a pulsed direct current, and a second built-in carrier waveform clears the charge that would otherwise build up, so it can deliver long, single-direction pulses you can tolerate comfortably. That long, distinctly different signal is what gives the nervous system something to lock onto.
This fits the way specialist FND physiotherapy already works, where the aim is to let movement become automatic again rather than forcing it by hand. Sessions rebuild your confidence in moving, retrain gait and limb control, and restore the brain's trust in pathways that still work.
How low-level laser therapy can help
FND leaves no structural damage to repair, so THOR low-level laser therapy plays a supporting role rather than a reparative one. Its value lies in the symptoms that travel alongside FND: chronic pain, muscle tension, fatigue. By easing inflammation and supporting cellular energy in the tissue, it lowers the physical background noise that makes movement retraining harder. Researchers are also starting to look at photobiomodulation's effects on brain regulation, though that work is early.
The combination within treatment
The two modalities come at FND from different angles. Laser leaves you calmer, less guarded, less fatigued. The NEUBIE then hands the nervous system a strong signal to reorganise around while guided exercise retrains the normal pattern. When it suits the case, dry needling releases protective muscle tension first. The goal stays constant throughout: make normal movement easier to reach, and easier to hold once you reach it.
The mechanism: why this approach works
The current model treats FND as a disorder of prediction and attention. The brain's internal predictions start to override normal sensorimotor processing, so voluntary movement turns unreliable even while reflexive and automatic movement carries on working. That gap explains why someone with functional weakness can fail to move a limb on command, then move it normally the moment they are distracted.
Good treatment works that gap deliberately. A strong, unfamiliar external input, plus a shift of attention onto the input instead of the symptom, lets the nervous system step past the faulty prediction and reach the movement it can still produce. The NEUBIE supplies the input and the focus. The laser quietens the competing pain and fatigue signals. Guided movement consolidates the pattern. Nothing in the system is broken, so each successful repetition helps rebuild reliable control over time.
Conclusion
In FND, the distinction between damaged and disrupted shapes what treatment can aim for. Your pathways work; the obstacle is access. That is why a structured, signal-led approach is worth your time. Pairing NEUBIE stimulation with THOR laser therapy and targeted manual work quietens the physical noise, gives the nervous system something clear to organise around, and retrains movement that has felt out of reach. Progress differs from one person to the next, and meaningful change is realistic.
Ready to take the next step?
If you live with FND and want to find out whether this approach could help you, book a free 30-minute consultation, in person or by phone. We will talk through your history, your symptoms and your goals, with no pressure and no assumptions.
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Evidence & references
Honest summary of the evidence behind this article:
The nature of FND (a disorder of nervous-system functioning with intact structures, often improvable) and the attention/movement-retraining principle are well established and consensus-supported [1,3]. Specialist physiotherapy is the recommended approach. The largest randomised trial to date (Physio4FMD) found specialist physiotherapy safe and valued but not statistically superior to community neurological physiotherapy on its primary outcome [2], so the evidence base supports the approach while still maturing.
The NEUBIE itself has not been studied in FND. Its use here rests on a mechanistic rationale: external stimulation and biofeedback line up with the established FND principle of redirecting attention and retraining automatic movement. That is not the same as a claim backed by FND-specific trials. The only published clinical trial of the device is in diabetic neuropathy [5].
On the waveform itself: the NEUBIE is a pulsed direct current (DC) device, not a continuous-DC or alternating-current one. Both the manufacturer and the peer-reviewed literature classify it that way [5,6]. The brand-independent evidence sits at the waveform level. One small crossover study found monophasic pulsed current produced higher muscle torque than a popular alternating-current waveform at the same tolerated intensity [7], and the one published NEUBIE RCT (in diabetic neuropathy, not FND) found it beat TENS on several nerve and symptom measures, though that trial was open-label, NeuFit-affiliated, and several effects weakened after correction for multiple comparisons [5]. In FND the relevant point is the novel, salient signal the waveform provides, not muscle recruitment. Further pulsed-DC trials in low back pain and radiculopathy are registered but not yet reporting [8]. Worth stating plainly: the well-studied "DC" technique in neurology, transcranial direct current stimulation (tDCS), is a different, low-intensity brain-surface method and is not what the NEUBIE delivers. Its results do not transfer to this approach.
Laser/photobiomodulation in FND has no condition-specific evidence. Its role is symptomatic (pain, tension, fatigue), drawing on PBM's general anti-inflammatory and analgesic effects [4].
Nielsen G, Stone J, Matthews A, et al. Physiotherapy for functional motor disorders: a consensus recommendation. J Neurol Neurosurg Psychiatry. 2015;86(10):1113–1119. https://pubmed.ncbi.nlm.nih.gov/25433033/
Nielsen G, Stone J, Lee TC, et al. Specialist physiotherapy for functional motor disorder in England and Scotland (Physio4FMD): a pragmatic, multicentre, phase 3 RCT. Lancet Neurol. 2024;23(7):675–686. https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(24)00135-2/fulltext
Aybek S, Perez DL. Diagnosis and management of functional neurological disorder. BMJ. 2022;376:o64. https://doi.org/10.1136/bmj.o64
Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337–361. https://doi.org/10.3934/biophy.2017.3.337
Kostopoulos D, et al. An open-label comparative study of pulsed direct current (Neubie) versus alternating current (TENS) in the physical therapy treatment of diabetic peripheral neuropathy. J Diabetes Res. 2025. https://pubmed.ncbi.nlm.nih.gov/39949402/
NeuFit. More about the Neubie (device description: pulsed direct current and dual-waveform design). https://www.neu.fit/more-about-the-neubie/
Scott W, et al. Electrically elicited muscle torque: comparison between 2500-Hz burst-modulated alternating current and monophasic pulsed current. J Orthop Sports Phys Ther. 2015. https://pubmed.ncbi.nlm.nih.gov/26556393/
NeuFit-sponsored pulsed direct current trials (registered, results pending): mechanical low back pain, ClinicalTrials.gov NCT06984224 (https://clinicaltrials.gov/study/NCT06984224); lumbosacral radiculopathy, ClinicalTrials.gov NCT06421558 (https://clinicaltrials.gov/study/NCT06421558).
Important information
This article is for general education and is not medical advice. It does not replace assessment, diagnosis or treatment from your GP or neurologist, and nothing here should be used to delay or stop conventional medical care.
The treatments described are delivered as part of individualised, off-label clinical care. In the UK, THOR low-level laser therapy is approved for tendinopathies, chronic joint pain, back and neck pain, and oral mucositis. Use for any other condition, including the one discussed here, is off-label and is not a claim to treat or cure that condition. The NEUBIE is a regulated neuromuscular stimulation device cleared for general indications such as neuromuscular re-education, preventing disuse atrophy, reducing muscle spasm and pain management. Its use in specific neurological conditions is supportive and off-label rather than an approved disease treatment.
Where evidence is referred to, its strength is described honestly (established, emerging, preclinical or mechanistic), and individual responses vary. No specific outcome is promised.
