Comparison of Treatment Outcomes From 6 Weeks of Home-Based Kinesio Taping and Transcutaneous Electrical Nerve Stimulation Combined With Self-Applied Myofascial Stretching in Adults With Carpal Tunnel Syndrome

Introduction

Carpal tunnel syndrome (CTS), the most common entrapment neuropathy, results from median nerve compression at the wrist [1], accounting for up to 90% of all neuropathies [2]. The global prevalence is 3–7%, with women affected about 3 times more than men [1]. In Taiwan, the annual incidence is ~0.4%, higher among women and those aged 50–59 years [3], with prevalence and risk factors similar to those in other Asian populations, including repetitive wrist activity, diabetes, and obesity [1]. Diagnosis relies on clinical assessment and, when needed, nerve conduction studies. Management ranges from conservative therapies to surgical decompression in severe cases [1]. CTS is more prevalent among workers who perform hand-intensive activities (7.8% in the U.S. [4], 10.5% in Taiwanese [5] laborers), impairing hand function, quality of life, and productivity. Accurate evaluation of functional impairments is essential to guide effective treatment.

In the post-Covid pandemic era, safe and effective rehabilitation programs suitable for use outside hospital settings are increasingly important for patients with mild CTS. These interventions can be independent performed conveniently [6]. Conservative treatments are generally recommended and include non-steroidal anti-inflammatory drugs (NSAIDs) [7], corticosteroid injections [8], and wrist splinting [9,10]. Although corticosteroids can provide greater symptom relief than NSAIDs [7], their use is associated with potential adverse effects [11]. Wrist splints remain a standard conservative treatment and can reduce symptoms, although they can limit joint range of motion [9,10]. Other therapeutic modalities, such as shockwave therapy [12], myofascial massage, and ultrasound [13], or mini-open release surgery [14], have demonstrated clinical benefits. However, these interventions are typically administered by trained clinicians, limiting their accessibility outside clinical settings.

Transcutaneous electrical nerve stimulation (TENS) is widely used clinically and its effectiveness is well-established [15,16]. The gate control theory of pain is the most widely accepted mechanism explaining the analgesic effects of TENS [17]. The TENS device is compact, easy to use, very safe, and has minimal adverse effects, making it suitable for home use after professional instruction. Kinesio taping (KT) enables CTS patients to consistently access expert stretching therapy and is cost-effective. It preserves joint range of motion while improving motor control by enhancing proprioception [18], and reduces swelling and pain through skin undulations that boost blood and lymphatic circulation [19]. KT can improve hand function and reduce pain [20,21] and is supported in clinical guidelines. These interventions can be conveniently performed at home, providing therapy for CTS patients with long-term symptoms who are unable to receive regular hospital-based rehabilitation. However, few studies have examined the therapeutic effects of non-invasive conservative interventions, such as KT and TENS, in patients with CTS.

Accurate assessment of hand function is essential for monitoring disease and evaluating treatment outcomes. In the present study, grip strength was measured using the Jamar hydraulic hand dynamometer, and pinch strength was assessed using a B&L pinch meter (tip, 3-jaw, lateral) (Jamar ICC=0.96–0.98, B&L pinch meter, interclass correlation coefficient [ICC]=0.81–0.98) [22,23]. Pain was rated using the visual analog scale (VAS) (acute pain, ICC=0.97) [24], hand dexterity was measured with the Modified Moberg Pick-up Test (MMPUT) (ICC=0.91) [25], and sensory discrimination was assessed using 2-point discrimination (2PD) (ICC=0.96–0.98) [26]. Clinical studies have shown these measures to be highly reliable, demonstrating their precision and practical applicability in clinical and research settings.

To determine the efficacy of a treatment regimen requires a follow-up period. Previous studies suggested that evaluation of the results of conservative treatment with CTS should include a follow-up of 4–6 weeks [1,27]. A recent study exploring CTS treatment consisted of 2 weeks of KT followed by a 4-week follow-up [28], and the results showed the KT is an effective, safe, and reliable conservative therapeutic choice. Therefore, this study aimed to compare treatment outcomes from 6 weeks of home-based KT and TENS combined with myofascial stretching in adults with CTS. We hypothesized that KT would produce greater improvements in pain, strength, sensory function, and hand dexterity compared with TENS in patients with CTS.

Material and Methods

ETHICS STATEMENT:

This study was approved by the Ethics Committee of China Medical University Hospital (No. CMUH103-REC3-072), and the trial was retrospectively registered on ClinicalTrials.gov (NCT06464809 on June 18, 2024).

PARTICIPANTS:

A total of 54 participants with symptoms and signs of CTS, confirmed by electrodiagnostic studies in the electrodiagnostic laboratory of a medical center, were enrolled. We included patients with at least 2 of the following symptoms and signs: (1) numbness and tingling in the median nerve territory of the hand, (2) nocturnal paresthesia, and (3) positive provocative tests (Tinel’s sign and Phalen’s test). The diagnosis was confirmed and severity classified using nerve conduction velocity (NCV) studies as mild CTS if the distal sensory latency (DSL) of the median nerve was >3.6 ms and the distal motor latency (DML) was <4.5 ms, or as moderate CTS if the DSL was >3.6 ms and the DML was >4.5 ms but <7 ms [29,30]. We excluded patients with confounding conditions, including cervical radiculopathy, polyneuropathy, metabolic or autoimmune diseases, wrist trauma or surgery, or pregnancy.

Twelve participants were excluded, including 8 who did not meet the inclusion criteria and 4 who declined to participate. Consequently, 42 participants with CTS were randomly assigned to either the KT (n=21) or TENS group (n=21) using a simple draw method, whereby allocation was determined by randomly selecting folded slips of paper containing the group assignments from a sealed container (Figure 1). Fifteen age- and sex-matched healthy participants without a history of CTS and no relevant medical or surgical conditions were enrolled as the control group. All subjects were informed about the study and provided written consent prior to enrollment.

KT INTERVENTION: Three precut KT I strips with a width of 5 cm were used. The first strip is applied with the subject’s wrist in fully extended hand position. The middle and ring fingers were placed through the holes with the base of the tape anchored to the metacarpophalangeal joint, and then the tape was applied with 15–25% tension, covering the palm and the wrist, and the remainder of the tape was applied without any tension from the wrist up to the forearm. The same process was repeated for the second I-strip, which was applied from the dorsum of the hand to the wrist while the wrist in a downward-flexed position. The final strip was applied to the carpal tunnel region with 25–35% tension (Figure 2A). This technique was applied to enlarge the carpal tunnel space, as described in a previous study [18].

TENS INTERVENTION: The TENS intervention was delivered using a portable Gem-Stim device (Gem-Stim, Gemore Technology Co., Ltd., Taiwan), which uses an asymmetrical biphasic square pulse waveform. The device allows user-adjustable stimulation intensity, frequency, and pulse duration, with a maximum output current of 80 mA. The Gem-Stim TENS unit was approved by the local regulatory authority as a certified medical device, indicating compliance with international safety and performance standards. Two electrodes were positioned 2 cm apart, with one over the carpal ligament on the affected side and the other placed proximally along the median nerve (Figure 2B). We used a high-frequency (150 Hz) conventional TENS and wide pulse width (200 μs) [36] for our treatment regimen, with the intensity adjusted according to the patient’s tolerance. The patient should experience a vibration or tingling sensation under the electrodes [37], guiding the patient to adjust treatment intensity.

SELF-APPLIED STRETCHING OF THE CARPAL LIGAMENT: Participants performed self-applied stretching of the carpal ligament, with each session following 4 steps [38]: (1) Stand facing a wall and place the affected hand flat against it at approximately shoulder height; (2) Using the opposite hand, gently retract the thenar eminence toward the forearm to apply mild tension to the carpal ligament; (3) Hold the stretch for 30 s, then slowly release; (4) Repeat the stretch 3 times per session, with a 10-s rest between repetitions. Participants were provided with written instructions and diagrams and asked to record each session in a log sheet.

EXPERIMENTAL DESIGN AND PROCEDURES:

This was a prospective, randomized, controlled trial. The participants who met the inclusion criteria were randomly assigned to the KT group or TENS group. All participants received treatment and education individually on a one-on-one basis and were blinded to the treatments used in the other group. The treatment lasted 6 weeks, with assessments conducted before and after treatment and at the 6-week follow-up. The KT group received taping for 2 days, reapplied after a 24-h rest period. The TENS group received 1 TENS session that lasted 30 min [39], with at least 30 sessions (5 sessions per week). Participants in both groups performed self-applied myofascial stretching of the carpal ligament for 30 s at a time, 4 times a day, and 5 days per week [38].

The KT intervention was applied by the same licensed physical therapist during scheduled home visits and was not fully self-administered. The home-based TENS program was initiated with standardized in-person instruction, followed by regular video conferencing sessions to verify correct electrode placement and device settings.

Supervision was conducted in real time and assessments were performed by the same therapist. Intervention adherence was monitored using self-recorded treatment logs. A control group of 15 participants was included for measurement of the grip and pinch strengths, 2PD, and MMPUT for comparison. The same researcher provided all the assessments across the 3 groups, and each participant was seen individually to minimize contamination across groups.

STATISTICAL ANALYSIS:

Power analysis used a power of 0.8 with an alpha level of 0.05, as calculated using G*Power 3.1 software. With these parameters and an effect size of 0.35, the minimum required total sample size was 20 patients (10 per group), which this study met. Unilateral CTS participants were assessed on the affected side and bilateral cases were assessed on the more severe side. Healthy participants were assessed on their dominant side. During the intervention period, 6 participants in each group discontinued participation in the study due to scheduling conflicts or for work-related reasons, loss of motivation, or loss to follow-up. No participants withdrew due to treatment-related adverse effects or worsening of symptoms. A total of 15 participants in each group completed the intervention and were included in the final analysis (Figure 1).

Statistical analyses were performed using SPSS 21.0 for Windows (SPSS, Inc., Chicago, IL, USA). Data normality was assessed using the Kolmogorov-Smirnov test. Demographic differences between groups were analyzed using independent t tests or one-way ANOVA for parametric data. When one-way ANOVA indicated a significant difference, post hoc comparisons between groups were performed using the Tukey test. We used the Mann-Whitney U test or the Kruskal-Wallis test for non-parametric data. Group (KT vs TENS) and time (pre-treatment, post-treatment, follow-up) effects were examined using repeated-measures ANOVA, with Bonferroni correction applied for post hoc pairwise comparisons. Effect sizes were reported as partial η² and interpreted as small (0.01–0.059), medium (0.06–0.139), or large (>0.14). For non-parametric outcomes, intergroup comparisons used the Mann-Whitney U test, and within-group comparisons used the Friedman test followed by the Wilcoxon signed-rank test for paired comparisons if significant. Sex distribution between groups was compared using the chi-square test. Statistical significance was set at P<0.05.

Results

DEMOGRAPHIC AND BASELINE CHARACTERISTICS:

Table 1 compares demographic and baseline characteristics. Baseline comparisons indicated no significant differences in sex, age, body weight, or height among the KT, TENS, and control groups. There were significant differences in hand grip (F=4.527, P=0.017), tip pinch (F=4.227, P=0.021), MMPUT (eyes open: F=5.102, P=0.010; eyes closed: F=5.940, P=0.005) and 2PDs (thumb: p=0.016; middle finger: P=0.014). Post hoc analysis indicated significantly lower hand grip strength (KT: P=0.027; TEMS: P=0.042) and tip pinch strength (KT: P=0.046; TEMS: P=0.036), as well as longer MMPUT times with both eyes open (KT: P=0.019; TEMS: P=0.027) and closed (KT: P=0.005; TEMS: P=0.048) (P<0.05) in both CTS groups compared to the control group. Additionally, the Mann-Whitney U test indicated larger 2PD values for the thumb (KT: P=0.033; TEMS: P=0.029) and middle fingers (KT: P=0.004; TEMS: P=0.029) in both CTS groups compared to the control group.

COMPARISONS IN THE KT AND TENS GROUPS:

Table 2 compares motor strength, sensory symptoms, and hand dexterity across time between the KT and TENS groups. Significant main effects of test time was observed for hand grip strength (F=17.767, P<0.001, η2=0.388), pinch strengths (tip: F=4.625, P=0.014, η2=0.142; 3-jaw chuck: F=6.244, P=0.004, η2=0.182), BCTQ scores (SSS: F=64.706, P<0.001, η2=0.698; FSS: F=26.316, P<0.001, η2=0.484), VAS score (F=68.010, P<0.001, η2=0.759), MMPUT with eyes closed (F=32.273, P<0.001, η2=0.538), and 2PD values (thumb: P<0.001; index finger: p<0.001; middle finger: P<0.001).

Pairwise comparisons indicated significant improvement in hand grip strength, BCTQ scores, VAS scores, and MMPUT with eyes closed before treatment and at follow-up (all: P<0.001). However, tip pinch and 3-jaw chuck pinch strengths indicated significant increases only after treatment compared to before treatment (P=0.007). The Wilcoxon signed-rank test indicated significant improvement in 2PD values of thumb finger (pre–post: P=0.028, pre–follow up: P=0.019), index finger (pre–post: P=0.033, pre–follow-up: P=0.016), and middle finger (pre–post: P=0.003, pre–follow-up: p=0.001) after treatment and at follow-up compared to before treatment. Additionally, the KT group had significantly lower VAS scores compared to the TENS group (F=5.792, P=0.023, η2=0.171) (Table 2).

INTERACTION EFFECTS BETWEEN GROUP AND TIME:

Significant interactions were observed for hand grip strength (F=5.814, P=0.005, η2=0.172), SSS scores (F=3.627, P=0.033, η2=0.115), VAS scores (F=10.804, P<0.001, η2=0.278), and MMPUT with eyes closed (F=6.870, P=0.002, η2=0.197) (Figure 3A, 3B). The KT group showed rapid improvement in hand grip strength, SSS, VAS score, and MMPUT with eyes closed after treatment, while the TENS group exhibited slower progress. This improvement was maintained through the follow-up.

Discussion

DEMOGRAPHIC AND BASELINE CHARACTERISTICS:

Participants with CTS exhibited notable deficits in hand grip strength, sensory perception in the thumb and middle fingers, and manual dexterity, with no significant differences in pinch strength except for reduced tip pinch strength (Table 1). The lower grip and tip pinch strength observed in CTS patients suggest impaired motor function caused by median nerve compression, which affects the thenar muscles and reduces fine motor control. Similar findings have linked median nerve dysfunction to reduced grip and pinch strength [40]. Addressing both sensory and motor deficits appears essential for optimizing functional recovery in this population.

Longer MMPUT times in CTS patients indicated impairment of manual dexterity and coordination. The loss of tactile sensation, often due to median nerve compression, reduced proprioception and made movement more challenging, supporting the idea that CTS impairs both motor and sensory pathways [41]. Increased 2PD values in CTS patients indicated lower tactile acuity, particularly in the thumb and middle fingers, which are primarily innervated by the median nerve. Elevated 2PD values in the thumb and middle fingers further highlighted sensory deficits, consistent with prior studies [42]. Tada et al found that sensory nerve conduction was often worse in the middle finger than in the index finger, possibly because the middle finger’s superficial nerve bundle was more vulnerable to compression [43,44].

INTERACTION EFFECTS BETWEEN GROUP AND TIME:

After the 6-week interventions, hand grip and pinch strengths (tip and 3-jaw chuck) improved in both the KT and TENS groups, with hand grip strength maintained through the follow-up period (Table 2). Both interventions were effective, and KT showed slightly larger gains in hand grip strength after treatment (11.2% vs 4.8% in the TENS group); however, these differences should be interpreted with caution. Previous studies suggested that KT can improve pain intensity and grip strength compared with no intervention, whereas splinting showed limited benefit [45], and KT was more effective than splinting when combined with physical therapy [46]. Previous studies have reported similar functional gains with KT in combination with other rehabilitation strategies [47–49]. In our study, all CTS participants performed self-applied myofascial stretching of the carpal ligament combined with KT or TENS treatment for 6 weeks, with both interventions producing improvements in grip and pinch strengths. Some participants were unable to fully achieve or maintain normal hand strength after treatment, consistent with the findings of Baker et al [40], indicating residual functional deficits.

After the interventions, KT and TENS both produced significant reductions in SSS and VAS scores, with improvements maintained through follow-up (Table, 2; Figure 3A). KT showed slightly larger reductions in SSS (33% vs 19.6%) and VAS scores (47.2% vs 24.0%) compared to TENS, although between-group differences should be interpreted cautiously, as both interventions yielded clinically meaningful improvements. Pain intensity correlates with functional disability [50], as increased pain can lead to fear-related movement avoidance and functional limitation. The analgesic effects of TENS are commonly attributed to stimulation of large-diameter afferent fibers and activation of spinal and supraspinal inhibitory mechanisms [51]. KT can provide additional sensory input supporting symptom relief, although the mechanisms were not directly examined. Adjunctive rehabilitation approaches, including shockwave therapy, KT, and EMS combined with active stretching, have been associated with improvements in pain and function [52,53], with TENS providing immediate pain relief but being less effective than EMS plus stretching in increasing pressure pain thresholds [54].

After the interventions, the KT and TENS groups both demonstrated significant improvements in hand dexterity, as assessed by the MMPUT with eyes closed, and these gains were maintained at follow-up (Figure 3B). The MMPUT was selected to evaluate hand dexterity because it requires a 3-finger pinch to manipulate small objects, thereby assessing both prehensile control and fine motor performance [25]. Previous studies have identified hand dexterity as an important indicator of functional performance in individuals with CTS [55]. The eyes-closed condition of the MMPUT further challenges sensory input and fine motor control, with slower performance in the absence of visual feedback, reflecting impaired tactile sensitivity [56]. Although the KT group showed slightly greater improvements in this proprioceptive-related task, both interventions produced clinically meaningful improvements. Consistent with the literature, we found that proprioceptive-oriented tasks can benefit from active or coordinated movement-based rehabilitation approaches compared to passive modalities such as TENS. However, further studies are required to clarify the specific mechanisms contributing to these improvements [57].

TREATMENT EFFECTS AND CLINICAL IMPLICATIONS:

Overall, KT and TENS both contributed to improvements in hand function, symptom severity, pain, and dexterity, with overlapping benefits observed across multiple outcomes, highlighting that both interventions can support functional recovery in CTS patients. The maintenance of improvements during follow-up suggests that physical therapy interventions such as KT are associated with more stable medium-term functional outcomes. Although KT required periodic application by a physical therapist during home visits, both KT and TENS were delivered at home, which ensured comparable home-based conditions while allowing evaluation of the impact of clinician-applied versus self-administered interventions on treatment fidelity, adherence, and outcomes. In contrast, the comparatively passive nature of TENS may partially account for its more gradual and less sustained effects, consistent with findings from chronic pain management studies [58]. Both interventions were feasible for home use, offering convenience, cost-effectiveness, and support for independent symptom management, and combining the active, movement-based approach of KT with the analgesic effects of TENS may provide a more comprehensive treatment strategy for CTS patients.

LIMITATIONS:

This study has several limitations. First, the sample size was relatively small and participant dropout occurred; however, the final analyzed sample exceeded the minimum required by the a priori power analysis (10 participants per group for 80% power). Second, healthy controls were included to provide normative reference values for grip strength, pinch strength, sensory thresholds, and dexterity, but the absence of a sham or untreated CTS control group remains a methodological limitation. Third, a sham intervention was not implemented due to practical and ethical considerations; nevertheless, previous studies have reported significantly greater and sustained improvements in pain and hand function with KT compared with sham taping [20,21]. Fourth, the intervention duration was limited to 6 weeks, restricting conclusions regarding long-term effects. In addition, the study used a single-blind design in which therapists were aware of group allocation, which may have introduced performance-related bias. This is particularly relevant for subjective outcomes, as perceptual differences between KT and TENS may have contributed to variability in self-reported pain ratings on the VAS. Finally, although both interventions were suitable for home use and were expected to promote good compliance, complete adherence could not be fully verified.

Conclusions

Our study demonstrated significant improvements in grip and pinch strength, BCTQ and VAS scores, MMPUT with eyes closed, and 2-point discrimination in the KT and TENS groups, maintained at follow-up. KT showed slightly greater improvements than TENS in some outcomes, including grip strength, symptom severity, pain, and manual dexterity; however, both interventions contributed to functional recovery and pain relief in individuals with carpal tunnel syndrome. These therapies ensure continuous care and medium-term therapeutic benefits. Future studies with larger sample sizes and longer follow-up periods are warranted, and strategies aimed at improving participant compliance are needed to better elucidate the clinical effectiveness of home-based KT and TENS interventions.