Changes in the excitability of anterior horn cells in a mental rotation task of body parts.

INTRODUCTION/AIMS: Mental rotation (MR), a tool of implicit motor imagery, is the ability to rotate mental representations of two- or three-dimensional objects. Although many reports have described changes in brain activity during MR tasks, it is not clear whether the excitability of anterior horn cells in the spinal cord can be changed. In this study, we examined whether MR tasks of hand images affect the excitability of anterior horn cells using F-wave analysis. METHODS: Right-handed, healthy participants were recruited for this study. F-waves of the right abductor pollicis brevis were recorded after stimulation of the right median nerve at rest, during a non-MR task, and during an MR task. The F-wave persistence and the F/M amplitude ratio were calculated and analyzed. RESULTS: Twenty participants (11 men and 9 women; mean age, 29.2 ± 4.4 years) were initially recruited, and data from the 18 that met the inclusion criteria were analyzed. The F-wave persistence was significantly higher in the MR task than in the resting condition (p = .001) or the non-MR task (p = .012). The F/M amplitude ratio was significantly higher in the MR task than in the resting condition (p = .019). DISCUSSION: The MR task increases the excitability of anterior horn cells corresponding to the same body part. MR tasks may have the potential for improving motor function in patients with reduced excitability of the anterior horn cells, although this methodology must be further verified in a clinical setting.

Preliminary Results of Branch Level, Brachial Plexus Peripheral Nerve Stimulation on a Non-Human Primate.

Restoring functional hand control is a priority for those suffering from neurological impairments. Functional electrical stimulation (FES) is commonly applied to assist with rehabilitation. However, FES applied intramuscularly typically results in complex surgeries requiring many implants. This paper presents the preliminary findings from a feasibility study focused on evaluating the potential to access the upper extremity peripheral nerves through a single surgical approach (axillary approach). A single Japanese macaque (macaca fuscata) monkey was used to validate the feasibility of this study. Four of the five peripheral nerves which control the upper extremity were exposed, and had multi-contact epineural cuffs implanted: median, radial, ulnar and musculocutaneous. The axillary nerve was not accessible for epineural cuff placement with the current surgical approach used in this study. Electrical stimuli were used to produce movement contraction patterns of muscles relevant to the innervated peripheral nerves. In addition, to assist in quantifying the outcome, evoked potentials were simultaneously recorded from five extrinsic forearm flexors during median nerve stimulation. This feasibility study demonstrated that the axillary approach enables electrode placement to four of the five peripheral nerves required for upper extremity control through a single skin incision.Clinical relevance- This study demonstrated that the electrode placement to most of the peripheral nerves that control the arm and hand can be done by a single surgical approach: axillary approach.

The sono-elastography evaluation of the immediate effects of neurodynamic mobilization technique on median nerve stiffness in patients with carpal tunnel syndrome.

OBJECTIVES: The stiffness of median nerve increases in carpal tunnel syndrome (CTS) even at mild stage of syndrome which could be regarded as a diagnostic criterion. The aim of this study was to evaluate the immediate effects of neurodynamic technique on median nerve stiffness and cross-sectional area (CSA) at wrist and elbow in individuals with CTS. MATERIAL AND METHODS: It was a quasi-experimental study. Twenty patients were recruited for this study. They were included if aged 18-65 years and diagnosed with CTS based on electrodiagnostic and clinical findings. The exclusion criteria were previous surgeries at wrist or elbow. Patients were assessed by shear wave sono-elastography before and immediately after one session of neurodynamic mobilization technique (NDM). The primary outcome measure was the stiffness of the median nerve at wrist and the secondary outcomes were nerve stiffness at elbow and CSA of nerve at wrist and elbow. RESULTS: Median nerve stiffness and CSA decreased significantly at wrist immediately after a session of NDM. These parameters also decreased at elbow but were not statistically significant. CONCLUSION: One session of NDM reduced the stiffness and CSA of median nerve at wrist in patients with CTS as detected by sono-elastography verifying that sono-elastography is able to quickly detect the immediate biomechanical changes of the median nerve.

Clinical efficacy of electroacupuncture-like magnetic therapy compared to conventional transcutaneous electrical nerve stimulation in individuals with carpal tunnel syndrome.

This study aimed to evaluate the clinical efficacy of an electroacupuncture-like magnetic therapy (ELMT) and conventional transcutaneous electrical nerve stimulation (TENS) in patients with carpal tunnel syndrome (CTS). A prospective randomized controlled trial in single-centre was conducted. Thirty-four CTS patients confirmed by electrodiagnostic study were randomized into TENS or ELMT group and completed a six-week treatment program. TENS or ELMT treatment was applied on acupuncture point PC-6 (Neiguan) and one selected hand acupoint. Therapeutic exercises were also included after the electrophysical modality. Their physical signs, motor and sensory performances, Boston Carpal Tunnel Questionnaire (BCTQ) scores, and results of electrodiagnostic study were evaluated. After treatments, both groups demonstrated significantly decreased BCTQ scores and positive rate of Tinel's sign in the major symptomatic side, which indicated improvements in the symptom severity and physical functions. Significant increases in distal sensory amplitude and nerve conduction velocity of the median nerve were only found in the ELMT group. Our study found either conventional TENS or ELMT plus therapeutic exercises could improve the symptomatology and physical provocation sign of CTS. The ELMT has additional improvement in the nerve conduction in patients with CTS.

Effects of high-intensity laser therapy on pain, functional status, hand grip strength, and median nerve cross-sectional area by ultrasonography in patients with carpal tunnel syndrome.

The aim of this study was to evaluate the effects of high intensity laser therapy (HILT) on pain, functional status, hand grip strength, and median nerve cross-sectional area by ultrasonography in patients with carpal tunnel syndrome. Sixty patients who were diagnosed with carpal tunnel syndrome were included in the study. The patients observed during the research were randomly divided into two groups with 30 patients in each group. Splint+ exercise and HILT (pulsed mode with a power of 8.0 W and energy density of 8 J/cm2 for 1.40 minutes for every 25 cm2, continuous mode with a power of 3.0 W and energy density of 80 J/cm2 for 11 minutes for each 25 cm2; total 10 sessions 5 days a week) were applied for 2 weeks for the first group, and splint+exercise and sham laser treatment were applied for 2 weeks for the second group. Randomization was undertaken with the assistance of a computer-generated random number table before beginning the treatment processes. The patients were evaluated with the determined scales before the treatment, at the end of the treatment, and at the 3rd month. Hydraulic hand dynamometer was used to measure hand grip strength, visual analog scale (VAS) for pain, Boston CTS Questionnaire to assess function, and ultrasonography to measure median nerve cross-sectional area. The impact of time on the change in VAS levels was found to be of statistical significance within each group of patients (p<0.001), but between-group comparisons did not yield significant results (p<0.454). The effects of time on variations in Boston CTS Questionnaire scores were found to have been of statistical significance for both groups (p<0.001), but significance was not subsequently observed when the results of the two groups were compared on a between-group basis (p=0.226 and p=0.973 for the FSS and SSS, respectively). While time had a statistically significant effect on the change in hand grip strength for both groups (p=0.000), between-group comparisons statistical significance finding in favor of HILT was found in the early period (p=0.012). The time-group association patterns of the groups showed significant difference (p=0.025). While time had a statistically significant effect on the changes in the median cross-sectional areas of the nerve for the patients of both treatment groups (p<0.001), between-group comparisons yielded no findings of statistical significance (p=0.438). The time-group relationship patterns of the groups were found to reflect statistical significance (p=0.001). In conclusion, the results of the research presented here have confirmed that hand grip strength may increase and the median nerve's cross-sectional area may decrease upon the application of high-intensity laser for individuals experiencing CTS. However, this effect was demonstrated here only in the short-term and the evidence was not maintained through the course of follow-up of a longer duration.

Anatomical proposal of local anesthesia injection for median nerve block in treating hyperhidrosis with botulinum neurotoxin.

INTRODUCTION: Hyperhidrosis, causing excessive sweat, can be treated with Botulinum neurotoxin injection. Botulinum toxin, an effective and safe treatment for hyperhidrosis, unfortunately involves significant pain due to multiple injections. This study aims to propose a more efficient and less painful approach to nerve blocks for relief, by identifying optimal injection points to block the median nerve, thereby enhancing palmar hyperhidrosis treatment. METHODS: This study, involving 52 Korean cadaver arms (mean age 73.5 years), measured the location of the median nerve relative to the transverse line at the pisiform level to establish better nerve block injection sites. RESULTS: In between the extensor carpi radialis and palmaris longus, the median nerve was located at an average distance of 47.39 ± 6.43 mm and 29.39 ± 6.43 mm from the transverse line at the pisiform level. DISCUSSION: To minimize discomfort preceding the botulinum neurotoxin injection, we recommend the optimal injection site for local anesthesia to be located 4 cm distal to the transverse line of the pisiform, within the tendons of the palmaris longus and flexor carpi radialis muscles.

Analgesic efficacy of median nerve stimulation in mice with chemotherapy-induced peripheral neuropathymodulation of brain-derived neurotrophic factor expression.

OBJECTIVE: Chemotherapeutic agents such as docetaxel (DTX) can trigger chemotherapy-induced peripheral neuropathy (CIPN), which is characterized by unbearable pain. This study was designed to investigate the analgesic effect and related neuronal mechanism of low-frequency median nerve stimulation (LFMNS) on DTX-induced tactile hypersensitivity in mice. METHODS: To produce CIPN, DTX was administered intraperitoneally 4 times, once every 2 d, to male ICR mice. LFMNS was performed on the wrist area, and the pain response was measured using von Frey filaments on both hind paws. Western blot and immunofluorescence staining were performed using dorsal root ganglion and spinal cord samples to measure the expression of brain-derived neurotrophic factor (BDNF). RESULTS: Repeated LFMNS significantly attenuated the DTX-induced abnormal sensory response and suppressed the enhanced expression of BDNF in the DRG neurons and spinal dorsal area. CONCLUSIONS: LFMNS might be an effective non-pharmaceutical option for treating patients suffering from CIPN regulating the expression of peripheral and central BDNF.

Comparison of 4 weeks of cupping and Kinesio-taping on clinical and ultrasound outcomes of carpal tunnel syndrome during pregnancy.

OBJECTIVE: To explore effect of cupping and Kinesio-taping techniques on clinical and ultrasound outcomes of carpal tunnel syndrome (CTS) during pregnancy. METHODS: Thirty pregnant women suffering from CTS were randomly assigned into Kinesio-taping (n = 15) and cupping (n = 15) groups. In Kinesio-taping group, individuals underwent Kinesio-taping for three days, one day with no treatment, and three days with Kinesio-taping, continuing this procedure for four weeks. In cupping group, cupping was moved for 5 min with pressure of 50 mm-Hg on the carpal tunnel area. This procedure continued longitudinally in forearm area for 2 min. The therapeutic intervention of cupping group continued with eight sessions, two days a week for 4 weeks. Ultrasound outcomes including median nerve cross-sectional area through ultrasonography, and clinical outcomes including pain through visual analog scale and severity of symptoms and functional status through Boston questionnaire were measured in both groups before and after therapeutic program. RESULTS: In both groups, a significant reduction was observed in all variables after treatment compared to pre-treatment (P < 0.001). In inter-group comparison, a significant improvement was found in outcomes of Boston questionnaire and ultrasound results about median nerve cross-sectional area at pisiform and hook of hamate in cupping group compared to Kinesio-taping at end of four weeks (P < 0.001). CONCLUSION: Both cupping and Kinesio-taping improved clinical and ultrasound outcomes of CTS. However, efficacy of cupping compared to Kinesio-taping was better in improvement of median nerve cross-sectional area at hamate hook and pisiform levels, symptoms severity scale, and functional status scale, which makes the results clinically more applicable.

Directional recordings of somatosensory evoked potentials from the sensory thalamus in chronic poststroke pain patients.

OBJECTIVE: The aim of this feasibility study was to investigate the properties of median nerve somatosensory evoked potential (SEPs) recorded from segmented Deep Brain Stimulation (DBS) leads in the sensory thalamus (VP) and how they relate to clinical and anatomical findings. METHODS: We analyzed four patients with central post-stroke pain and DBS electrodes placed in the VP. Median nerve SEPs were recorded with referential and bipolar montages. Electrode positions were correlated with thalamus anatomy and tractography-based medial lemniscus. Early postoperative clinical paresthesia mapping was performed by an independent pain nurse. Finally, we performed frequency and time-frequency analyses of the signals. RESULTS: We observed differences of SEP amplitudes recorded along different directions in the VP. SEP amplitudes did not clearly correlate to both atlas-based anatomical position and fiber-tracking results of the medial lemniscus. However, the contacts of highest SEP amplitude correlated with the contacts of lowest effect-threshold to induce paraesthesia. CONCLUSIONS: SEP recordings from directional DBS leads offer additional information about the neurophysiological (re)organization of the sensory thalamus. SIGNIFICANCE: Directional recordings of thalamic SEPs bear the potential to assist clinical decision-making in DBS for pain.

Transcutaneous electrical nerve inhibition using medium frequency alternating current.

Transcutaneous medium-frequency alternating electrical current is defined as an alternating current between 1 and 10 kHz and is capable of producing an instant, reversible block. This study aims to evaluate the efficacy of sensory perception and force production of the index and middle finger after transcutaneous medium-frequency alternating electrical current stimulation of the distal median nerve. A single-center prospective interventional cohort study was conducted in adult healthy volunteers at the Jessa Hospital, Hasselt, Belgium. Two different electrodes (PALS & 3M) were placed on the distal median nerve, which was located using a Sonosite X-Porte Ultrasound transducer, with the first electrode being placed on the skin at the level of the transverse carpal ligament and the second electrode 7 cm proximally to the first electrode. The tactile sensation was evaluated with Semmes-Weinstein monofilament test and sensation of pressure/pain was evaluated with an algometer. Peak force production was assessed with an electronic dynamometer. All measurements were performed at baseline and tMFAEC stimulation frequencies of 2 and 10 kHz in a randomized manner. Statistical analysis was performed with a one-way ANOVA with repeated measures test or a Friedman rank sum test, followed by the Wilcoxon signed rank test adjusted with Bonferroni correction. A p-value < 0.05 was considered statistically significant. From 9 to 13th of April 2021, 25 healthy volunteers were included in the Jessa Hospital, Hasselt, Belgium. A statistically significant reduction in tactile sensation during 2 kHz and 10 kHz stimulation compared to baseline was observed (2.89 ± 0.22 (PALS2); 3.35 ± 0.25 (3M2) and 2.14 ± 0.12 (PALS10); 2.38 ± 0.12 (3M10) versus - 1.75 ± 0.09 (baseline), p < 0.0001). 3M electrodes showed a tendency towards the elevation of pressure pain threshold compared to baseline. No significant difference in mean peak forces of the index and middle fingers after transcutaneous medium-frequency alternating electrical current stimulation with 2 and 10 kHz was found. This study demonstrates that transcutaneous medium-frequency alternating electrical current stimulation on the distal median nerve inhibits tactile sensory nerve activity in the index and middle finger when stimulation of 2 kHz and, to a lesser extent, 10 kHz was applied. A reduction of motor nerve activity was not observed but force production measurements may be prone to error.Trial registration: clinicaltrials.gov on 01/04/2021. NCT-Number: NCT04827173.

Does hyperbaric oxygen therapy facilitate peripheral nerve recovery in upper extremity injuries? A prospective study of 74 patients.

PURPOSE: Several experimental studies have investigated the effects of hyperbaric oxygen therapy (HBOT) on peripheral nerve regeneration. However, to the best of our knowledge, clinical studies to evaluate the effects of HBOT on peripheral nerve recovery are seldom performed. The aim of our study was to investigate the efficacy of HBOT following primary nerve repair in patients with upper extremity nerve injuries. METHODS: Patients admitted to our hospital between 2015 and 2019 with ulnar and median nerve injuries were included in the study. Patients were randomized based on their application dates and divided into two different groups. Patients who received HBOT following standard epineural nerve repair were included in group 1, while patients who only underwent epineural nerve repair were included in group 2. All patients were followed up at 3, 6, and 12 months post-treatment and evaluated through electroneuromyography analysis of the traumatized nerve, injured nerve-related muscle strength, and two-point discrimination test. RESULTS: Impulse transmission of injured nerves to the end organ was faster in group 1. Further, ENMG parameters demonstrated that injured nerves of patients in group 1 recovered faster. Patients in group 1 also reached higher power score and had significantly more rapid motor recovery than patients in group 2. CONCLUSION: This prospective study of upper extremity injuries demonstrated the favorable effects of HBOT on nerve recovery both clinically and electrophysiologically following nerve repair. One HBOT session each day for 5 days after surgical treatment can decrease morbidity and facilitate recovery.

Investigation of the Optimal Parameters of Median Nerve Stimulation Using a Variety of Stimulation Methods and Its Effects on Heart Rate Variability: A Systematic Review.

OBJECTIVES: There is a wealth of literature supporting the use of median nerve stimulation (MNS) for modulating autonomic nervous system (ANS) dysfunction such as in hypoxia, recovery after heart valve replacement, ischemia, and cardiac contractibility. Heart rate variability (HRV) is considered a gold standard for measuring autonomic modulation and dynamic nonlinear ANS processes through the use of an electrocardiogram (ECG). Although the use of MNS on HRV in animals and humans has been documented, optimal stimulation parameters are yet to be outlined. MATERIALS AND METHODS: This review aims to synthesize findings of neurostimulation using MNS on animals and humans while observing HRV using an ECG. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines with search parameters of "Median nerve stimulation," "Neiguan," "PC-6," "HRV," "Heart rate variability," and "Heart-rate variability" observing on animals and human subjects, we found a total of 17 eligible articles. RESULTS: In this review, changing two parameters, that is, stimulation frequency and side of stimulation, appears to be the most influential in effecting frequency-domain ECG analysis of HRV. However, it is evident from this review that to perform an effective comparison of the effects of MNS on HRV, more detailed reports of the studies are required. CONCLUSIONS: Finding the optimal stimulation parameters for MNS is crucial for improving HRV. This will in turn contribute to normalizing ANS function impaired in numerous clinical conditions, such as epilepsy or diabetes.

Treatment of carpal tunnel syndrome by low-level laser therapy versus corticosteroid injection: a randomized, prospective clinical study.

To compare the effects of low level laser therapy (LLLT) and corticosteroid injection in patients with moderate carpal tunnel syndrome (CTS). Eighty-seven patients (143 wrists) with moderate CTS were randomized to the corticosteroid or LLLT groups. 40 mg of triamcinolone acetate solution was applied to carpal tunnel of 44 patients (74 wrist). LLLT was applied to 43 patients (70 wrist) five times a week, for a total of 15 sessions (fluence of 6 j/cm2 for 1 min per point at a wavelength of 830 nm). Outcome measures were numbness and pain, QuickDASH questionnaire, grasping tests, Tinel and Phalen tests, electrophysiological tests and MRI evaluations, which were tested at the baseline and 1st and 6th months after the treatment. Eighty patients (133 wrists) completed the study at the end of 6 months. VAS and Quick DASH scores were better in the corticosteroid group in the 1st month, but there were no significant differences between groups in the 6th month. Phalen and Tinel tests, strength tests, and motor distal latency improved significantly and similarly in both groups at the 1st and 6th months. Sensory distal latency and sensory nerve conduction velocity showed significant improvements in the 1st and 6th months only in the corticosteroid group. In both groups, median nerve intensity rate and palmary spring rate improved significantly after the treatment. Based on this study, corticosteroid injection and LLLT groups showed statistically significant difference at the 1st month (short-term), whereas there was no significant difference at the 6th month (intermediate-term).

[Moderate bilateral carpal tunnel syndrome improved by median nerve neurodynamic mobilization: a case report]. / Syndrome du canal carpien bilatéral modéré amélioré par la mobilisation neurodynamique du nerf médian: à propos d'un cas.

Carpal tunnel syndrome is the most common neuropathy affecting the upper limb. Several therapeutic approaches are used to treat this syndrome, including conservative treatment, often used as the first line treatment. We here report the case of a 61-year-old female patient, presenting to the Department of Clinical Neurophysiology of the Specialty Hospital, Rabat, with moderate and bilateral carpal tunnel syndrome with sensory loss confirmed by electroneuromyography (ENMG). Manual therapy, including bilateral median nerve neurodynamic mobilization, was performed. Patient´s outcome was marked by disappearance of nocturnal numbness and follow up ENMG showed a marked improvement in nerve conduction parameters. Based on this positive result, neurodynamic mobilization of the median nerve may be considered as a possible approach for the conservative treatment of carpal tunnel syndrome.

Ring finger sensory latency difference in the diagnosis and treatment of carpal tunnel syndrome.

OBJECTIVE: To explore the sensitivity of median and ulnar nerve sensory latency differences in diagnosing carpal tunnel syndrome (CTS) at different severities. METHODS: CTS patients were divided into three groups based on disease severity (mild, moderate, and severe). Distal latency of sensory nerve action potential (SNAP) for the median and ulnar nerves was recorded. The sensitivity of SNAP distal latency to CTS and its correlation with CTS severity were analyzed. RESULTS: Significant differences were found in the median nerve sensory action potential distal latency (MSDL) and in the median and ulnar sensory latency difference to ring finger (MUD) but not in the ulnar nerve sensory action potential distal latency (USDL) between CTS and control. The sensitivity and specificity were 92.2 and 99.4% with an MSDL cutoff value of 2.40 ms, respectively, and were both 100% with a MUD cutoff value of 0.33 ms. There was no significant difference in USDL among the CTS and control groups. Significant differences were found in MSDL and MUD among the CTS severities and between mild and moderate CTS, but not between mild and severe CTS or between moderate and severe CTS. Correlations with CTS severity were observed for MSDL and MUD but not for USDL. CONCLUSION: The ulnar nerve of the CTS patients was not damaged. A smaller MSDL reflected median nerve damage, which can be used for the early diagnosis of CTS. MUD correlated with CTS severity with a higher sensitivity than MSDL, which can provide therapeutic insight without pain to patients.

Tocotrienol-Rich Vitamin E (Tocovid) Improved Nerve Conduction Velocity in Type 2 Diabetes Mellitus Patients in a Phase II Double-Blind, Randomized Controlled Clinical Trial.

Diabetic peripheral neuropathy (DPN) is the most common microvascular complication of diabetes that affects approximately half of the diabetic population. Up to 53% of DPN patients experience neuropathic pain, which leads to a reduction in the quality of life and work productivity. Tocotrienols have been shown to possess antioxidant, anti-inflammatory, and neuroprotective properties in preclinical and clinical studies. This study aimed to investigate the effects of tocotrienol-rich vitamin E (Tocovid SuprabioTM) on nerve conduction parameters and serum biomarkers among patients with type 2 diabetes mellitus (T2DM). A total of 88 patients were randomized to receive 200 mg of Tocovid twice daily, or a matching placebo for 12 months. Fasting blood samples were collected for measurements of HbA1c, renal profile, lipid profile, and biomarkers. A nerve conduction study (NCS) was performed on all patients at baseline and subsequently at 2, 6, 12 months. Patients were reassessed after 6 months of washout. After 12 months of supplementation, patients in the Tocovid group exhibited highly significant improvements in conduction velocity (CV) of both median and sural sensory nerves as compared to those in the placebo group. The between-intervention-group differences (treatment effects) in CV were 1.60 m/s (95% CI: 0.70, 2.40) for the median nerve and 2.10 m/s (95% CI: 1.50, 2.90) for the sural nerve. A significant difference in peak velocity (PV) was also observed in the sural nerve (2.10 m/s; 95% CI: 1.00, 3.20) after 12 months. Significant improvements in CV were only observed up to 6 months in the tibial motor nerve, 1.30 m/s (95% CI: 0.60, 2.20). There were no significant changes in serum biomarkers, transforming growth factor beta-1 (TGFß-1), or vascular endothelial growth factor A (VEGF-A). After 6 months of washout, there were no significant differences from baseline between groups in nerve conduction parameters of all three nerves. Tocovid at 400 mg/day significantly improve tibial motor nerve CV up to 6 months, but median and sural sensory nerve CV in up to 12 months of supplementation. All improvements diminished after 6 months of washout.

Essential tremor amplitude modulation by median nerve stimulation.

Essential tremor is a common neurological disorder, characterised by involuntary shaking of a limb. Patients are usually treated using medications which have limited effects on tremor and may cause side-effects. Surgical therapies are effective in reducing essential tremor, however, the invasive nature of these therapies together with the high cost, greatly limit the number of patients benefiting from them. Non-invasive therapies have gained increasing traction to meet this clinical need. Here, we test a non-invasive and closed-loop electrical stimulation paradigm which tracks peripheral tremor and targets thalamic afferents to modulate the central oscillators underlying tremor. To this end, 9 patients had electrical stimulation delivered to the median nerve locked to different phases of tremor. Peripheral stimulation induced a subtle but significant modulation in five out of nine patients-this modulation consisted mainly of amplification rather than suppression of tremor amplitude. Modulatory effects of stimulation were more pronounced when patient's tremor was spontaneously weaker at stimulation onset, when significant modulation became more frequent amongst subjects. This data suggests that for selected individuals, a more sophisticated control policy entailing an online estimate of both tremor phase and amplitude, should be considered in further explorations of the treatment potential of tremor phase-locked peripheral stimulation.