IBRO Neuroscience Reports 11 (2021) 194–199 Contents lists available at ScienceDirect IBRO Neuroscience Reports journal homepage: www.sciencedirect.com/journal/IBRO-Neuroscience-Reports Transcutaneous electrical nerve stimulation in the management of calf muscle spasticity in cerebral palsy: A pilot study Delali Logosu a, Thomas A. Tagoe a,*, Patrick Adjei b,c a Department of Physiology, University of Ghana, Accra, Ghana b Department of Medicine and Therapeutics, University of Ghana, Accra, Ghana c Department of Medicine and Therapeutics, Korle-Bu Teaching Hospital, Accra, Ghana A R T I C L E I N F O A B S T R A C T Keywords: This study sets out to evaluate the effectiveness of transcutaneous electrical nerve stimulation (TENS) in the Cerebral palsy management of calf muscle spasticity in children with cerebral palsy. The study follows a one group pre-test–- H-reflex post-test design involving fifteen children with spastic cerebral palsy, presenting with calf muscle spasticity. Modified Ashworth Scale Spasticity was assessed before and after a 30 min application of TENS to the bilateral calf muscles. The H-reflex Range of motion Spasticity (electromyography) of the calf muscles and Modified Ashworth Scale (MAS) served as a measure of spasticity. A Transcutaneous electrical nerve stimulation goniometer was used to measure the range of motion (ROM) angles for ankle dorsiflexion. We report here no significant difference (p > 0.05) between the left and right H-reflex responses, MAS scores, and ROM scores recorded at baseline (pre-test). Correlation analysis show no correlation (p > 0.05) between the pre-test HA Max (maximum H-reflex amplitude)/MA Max (maximum M-Wave Amplitude) ratio and MAS scores of both the left and right calf muscles. However, TENS significantly reduced (p < 0.05) the HA of the left calf muscle and MAS scores of the left and right calf muscles. Additionally, TENS significantly increased the ROM scores of the left and right calf muscles. Our findings lend support to existing evidence that TENS is effective in reducing spasticity. The potential mechanism underlying this effect is a reduction in neuron excitability. 1. Introduction stand, ambulate, and perform activities of daily living (Lin et al., 2016). Furthermore, it limits the range of motion (ROM) available at the ankle Cerebral palsy describes ‘a group of permanent disorders that affect joint (Sheean, 2008). Spasticity can be assessed subjectively using the the development of movement and posture, causing limitation in ac- Modified Ashworth Scale (MAS), which is a spasticity grading scale, and tivity. It is attributed to non-progressive disturbances in the developing objectively by electromyography (EMG), as an electrophysiological foetal or infant brain’ (Rosenbaum et al., 2007). There are four major reference. EMG is a standard tool for the assessment of the integrity of classifications of cerebral palsy based on the neuromuscular presenta- the peripheral nervous system. This is achieved via nerve conduction tion including spastic, dyskinetic (athetoid and dystonic), ataxic, and studies, muscle activity recordings, and reflex responses such as the F mixed cerebral palsy (Sankar and Mundkur, 2005). Globally, spastic waves, H waves, or blink reflexes elicited by a single or repetitive stimuli cerebral palsy is the most common type, accounting for 70–80% of all and recorded using a needle or surface electrode (Katirji, 2016). The cerebral palsy cases (Sankar and Mundkur, 2005; Wolting, 2018). In H-reflex and F wave have been identified as a reliable measure of Africa and in Ghana, spastic cerebral palsy may account for more than spasticity, with H-reflex being effective in assessing spasticity in chil- 60% of all cerebral palsy cases (Adei-Atiemo et al., 2015; Abas et al., dren with cerebral palsy (Tekgul et al., 2013; Katirji, 2016). Tekgul et al. 2017). (2013) reported a strong correlation between MAS and the H-reflex in Spasticity is an impairment that distorts motor function after a brain assessing spasticity. injury (Boyd and Ada, 2008; Alabdulwahab and Al-Gabbani, 2010). In The various management strategies for spasticity include stretches, spasticity, a velocity-dependent increase in resistance to passive move- strengthening, casting, nerve or muscle blocks, medications, tendon ment, presenting as hypertonia and muscle tightness, is observed lengthening, dorsal rhizotomy, and therapeutic electrical stimulation (Rethlefsen et al., 2010). Calf muscle spasticity affects a child’s ability to (TENS, Neuromuscular Electrical Stimulation [NMES], and Functional * Correspondence to: Department of Physiology – Basic Sciences Building, University of Ghana – Korle Bu Campus, Ghana. E-mail address: tatagoe@ug.edu.gh (T.A. Tagoe). https://doi.org/10.1016/j.ibneur.2021.09.006 Received 16 September 2020; Accepted 28 September 2021 Available online 2 October 2021 2667-2421/© 2021 Published by Elsevier Ltd on behalf of International Brain Research Organization. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). D. Logosu et al. I B R O N e u r o s c i e n c e R e p o r t s 11 (2021) 194–199 Electrical Stimulation [FES]) (Ved and Shah, 2017). There is paucity of EMG system (CADWELL®, USA). Participants were positioned information on the available treatment options for spasticity in Ghana; comfortably in the prone position over a pillow. The skin was cleaned, however, in practice, it is managed pharmacologically (mostly with and a tape measure and pen were used to indicate eight equal divisions baclofen, a GABAB receptor activator), and/or non-pharmacologically between the popliteal fossa and the medial malleolus. Two disposable (mostly by physiotherapy interventions). Recent studies have proven surface electrodes (GS27 Pre-gelled Disposable sEMG Electrodes, Bio- TENS to be effective in reducing spasticity in various conditions such as medical instruments, Inc., New Jersey-United States of America) were spastic cerebral palsy (Aydin et al., 2005; Sultan et al., 2005; Mills and used for each stimulation. The active electrode was placed on the 6th Dossa, 2016). Although this stimulation is available in Ghana, it is used division, and the reference electrode was placed on the last division to manage other symptoms like pain and paresis, but not spasticity, in (close to the Achilles tendon). A silver plate ground electrode was placed various physiotherapy centres. Exploring the use of TENS within the between the popliteal fossa and the active electrode (i.e., on the 3rd Ghanaian context may provide information on its effectiveness in division). A bipolar electrode connected to a bipolar electrical stimu- spasticity management, considering its availability and ease of accessi- lator of the EMG unit was placed in the popliteal fossa to stimulate the bility in various physiotherapy centres, where cerebral palsy is also tibial nerve. The EMG system was set to deliver rectangular pulses with a managed. This study hypothesized that, TENS can cause a reduction in width of 1 ms at a stimulation frequency of 0.1 Hz. The stimulation spasticity as measured by both objective (EMG) and subjective (MAS and started at a low intensity of 9.5 mA and was increased in 0.5 mA in- ROM) parameters. Therefore, we aimed to evaluate the effectiveness of crements until an intensity of 19.0 mA was attained (this corresponded TENS in the management of spastic cerebral palsy. to 20 stimulations). The sweep speed and sensitivity were set at 10 ms/D and 5 mV/D, respectively. H-reflex and M-wave responses triggered by 2. Material and methods each of the 20 stimulations were recorded. H-reflex and M-wave re- sponses of the left and right calf muscles were assessed pre-TENS and 2.1. Study design post-TENS. The goniometer is commonly used to assess ROM limitation in A quasi-experimental one group pre-test–post-test design was used in spasticity (Soucie et al., 2011). A 360◦ head–12-in. arm universal this study. This study was conducted according to the ethical standards goniometer (BASELINE® Plastic Goniometers, New York) was used to for the operation of the devices used, and it was approved by the ethical assess ROM by measuring the passive dorsiflexion angle at the ankle and protocol review committee of College of Health Sciences, University joints. The children were positioned comfortably in the supine position of Ghana. on the assessment bed with both lower limbs maintained in extension by a non-examiner. The centre of the goniometer was placed over the 2.2. Study site lateral malleolus of the fibula, with the stationary arm parallel to the lateral side of the fibula and the movement arm parallel to the lateral This study was conducted at the neurophysiology unit of the side of the 5th metatarsal. The ankle was moved passively to obtain Department of Medicine and Therapeutics, Korle-Bu Teaching Hospital. maximum dorsiflexion. The movement arm was then aligned parallel to the lateral side of the 5th metatarsal bone. The angle observed on the 2.3. Study participants goniometer was recorded for the left and right ankles. ROM measure- ments were performed twice for each measurement at baseline (pre-- Fifteen children with spastic cerebral palsy attending the Korle-Bu TENS) and post intervention (post-TENS) by the investigator for Physiotherapy Unit who met the inclusion criteria were recruited for intrarater reliability. this study using purposive sampling. The research procedure was After the baseline assessments, TENS 3000 Analog Unit (ROSCOE explained to all parents/guardians, and they all signed a written MEDICAL, Strongsville-Ohio) was used to deliver an asymmetrical informed consent form. The children were not prevented from attending biphasic square pulse via a non-invasive portable two-channel electrode regular physiotherapy sessions prior to and after the study. connected to disposable self-adhesive electrode pads (FITOP TENS pads, EUROBYTECH, Macon-France). Prior to electrode placement, the skin 2.4. Inclusion and exclusion criteria was cleaned with an alcohol-based cleaning towel. The electrodes were placed three fingers apart (the negative electrode was placed proxi- Inclusion criteria: Children from the ages of 1–11 years who had been mally, and the positive electrode was placed distally) over the belly of diagnosed with spastic cerebral palsy. the calf muscle. Stimulations were delivered to each calf muscle at a low Exclusion criteria: Children with a history of seizures, those who could intensity setting of 2, which served as a suprathreshold stimulation not lie prone, and those who could not react to pain. capable of inducing mild tingling sensations (intensity ranged from 0 to 5, where 0 is the least intensity, and 5 is the maximum intensity). This 2.5. Procedure was performed with children comfortably positioned in prone on the assessment bed. Baseline assessment of the level of spasticity using the MAS and H- All children received 30 min of conventional TENS (continuous reflex responses (H-reflex amplitude [HA], H-reflex latency [HL], and H- stimulation with all parameters constant) with a frequency of 100 Hz reflex amplitude maximum/M-wave amplitude maximum [HA Max/MA and a pulse width of 200 µs. Subsequently, the calf muscles were reas- Max ratios]) was performed on the bilateral calf muscles of the study sessed for spasticity using the H-reflex and MAS, and the angle of ankle participants by a licensed physiotherapist and neurologist, respectively. dorsiflexion was assessed using the universal goniometer. The children MAS assessment was performed with children in the supine position were allowed at least a 10-minute rest upon arrival at the neurophysi- on an assessment bed. The level of spasticity was assessed by passively ology unit before the procedures begun. dorsiflexing the ankle joint from a neutral position with the knee in extension. The resistance felt during the movement was graded and 2.6. Statistical analysis scored on the 6-point MAS with scores ranging from 0 to 5 (where 0 is no resistance and 5 is joint stiffness). The unexamined limb was kept stable Statistical analyses were computed using version 23 of the SPSS by a non-examiner during the assessment. The investigator (licensed software (BM, Armonk, NY, USA). Both descriptive and inferential sta- physiotherapist) performed the measurements twice for each lower tistics were used to summarise and present the data. limb, before and after the TENS. For the descriptive statistics, mean ± standard deviation was used to H-reflex responses were obtained using a Cadwell Sierra II Wedge present age distribution and heights of the children. The most preferred 195 D. Logosu et al. I B R O N e u r o s c i e n c e R e p o r t s 11 (2021) 194–199 position at home, the gender, and children’s routine medications were Table 2 recorded and presented as frequencies. Differences in baseline EMG characteristics between the left and right calf For the inferential statistics, non-parametric tests were used to muscles. analyse the data because the data was not normally distributed. Man- EMG Left (IQR) Right (IQR) U p- n–Whitney U test was used to analyse median differences between left measures value value and right EMG, MAS, and ROM scores. A correlation analysis was per- HA (mv) 0.228 (0.182–0.318) 0.181 (0.138–0.461) 106 0.775 formed to assess the correlation between MAS and HA Max/MA Max HA Max/MA 0.039 (0.032–0.068) 0.043 (0.030–0.052) 110 0.935 ratios. Wilcoxon signed rank test was used to analyse median differences Max between pre-TENS and post-TENS EMG measures, MAS scores, and ROM HL (ms) 61.800 58.000 104 0.744 (58.200–72.200) (55.800–78.000) angles. The confidence and significance levels were set at 95% and p < 0.05, respectively. Unless otherwise stated, the data are presented as EMG scores are presented in medians. Statistical significance: p < 0.05. median (IQR). EMG, electromyography; HA, H-reflex amplitude; HA MAX/MA MAX; H-reflex amplitude maximum/M-wave amplitude maximum; HL, H-reflex latency; IQR, interquartile range. 3. Results Participants (10 males and 5 females) were aged from 1 to 10 years (mean age: 5.10 ± 2.93 years) with heights ranging from 67.0 to 112.5 cm (mean height: 91.47 ± 14.60 cm). The children’s characteristic de- tails are presented in Table 1. 3.1. Baseline characteristics of calf muscle spasticity as measured by Electromyography (EMG) and Modified Ashworth Scale (MAS) Prior to TENS application, there was a need to assess baseline char- acteristics of both calf muscles using the three measures namely EMG, MAS, and ROM. The following three EMG parameters were recorded: HA (left: 0.228 mV; right: 0.181 mV; p = 0.775), HL (left: 61.8 ms; right: 58.0 ms; p = 0.744), and HA Max/MA Max ratios (left: 0.039; right: 0.043; p = 0.935). There was no significant difference in the three baseline EMG measures between the left and right calf muscles (p > 0.05; Table 2). Participants’ MAS scores ranged from 0 to 4, with a median value of Fig. 1. MAS scores. Left and right MAS median scores of participants as 2 for the left and right calf muscles. Similar to the EMG measures, there recorded prior to TENS application. There was no significant difference in the was no statistically significant difference in the median MAS scores MAS scores between the calf muscles (n = 15; U = 110, p = 0.935). MAS, between the left and right calf muscles (p = 0.935, Fig. 1). Of the 15 Modified Ashworth Scale; TENS, transcutaneous electrical nerve stimulation. participants, only one had a MAS score of 0 on both the left and right calf muscles although she had an observable lower limb spasticity, sug- difference in median dorsiflexion ROM angles between the left (10◦) and gesting that the position in which the test was performed might have right (12◦) ankle joints (U = 107.5, p = 0.838). influenced the spastic presentation. In addition to establishing the baseline measures, we queried ROM was our third baseline measure performed prior to the TENS whether there was a relationship between HA Max/MA Max ratios and application. The results obtained showed no statistically significant MAS. Such a correlation can be useful to clinicians in limited resource settings as it will help determine whether a MAS test can be used in place Table 1 of an EMG test. There was no correlation between left pre-TENS MAS Demographic characteristics presenting data on gender, age, height, most scores and HA Max/MA Max ratios (r = 0.307, n = 15, p = 0.133) and preferred position, and medication categories description of participants. right pre-TENS MAS scores and HA Max/MA Max ratios (r = − 0.015, Number of n = 15, p = 0.479). participants (%) GENDER MALE 10 (66.7) FEMALE 5 (33.3) 3.2. Effect of TENS on EMG measures, MAS, and ROM MOST PREFERRED SUPINE 5 (33.3) POSITION OF CHILDREN SUPINE BUT CAN ROLL 3 (20.0) Having established the baseline parameters (EMG, MAS, and ROM), AT HOME SIDE LYING AND PRONE 1 (6.7) SIDE-LYING ALONE 1 (6.7) we applied the TENS and repeated the measures. TENS application did ACTIVE 5 (33.3) not have a significant effect on the HA of the right calf muscle (pre- MEDICATION CATEGORIES NO MEDICATION 6 (40.4) TENS: 0.181 mV, post-TENS: 0.208 mV; Z = − 1.364; p = 0.08). How- SPASTICITY MEDICATION 5 (33.3) ever, TENS significantly decreased the median HA recorded on the left SPASTICITY MEDICATION 3 (20.0) PLUS ANY OTHER calf muscle from 0.228 mV to 0.168 mV (Z = 0.534; p = 0.011). This MEDICATION decrease was also expressed in the average left and right calf muscle OTHER MEDICATIONS 1 (6.7) median scores, which decreased from 0.24 mV to 0.204 mV AGE (YEARS) MEAN AGE ± SD 5.10 ± 2.93 (Z = − 2.530; p = 0.005, Fig. 2A). Individual participant values that RANGE 1–10 make up this average decrease are presented in Table 3. MEAN AGE (MALES) 5.90 ± 2.88 MEAN AGE (FEMALES) 3.5 2.55 Despite the significant decrease in the HA of the left calf muscle, ± HEIGHT (cm) MEAN HEIGHT ± SD 91.47 ± 14.60 TENS did not affect the left HL (pre-TENS: 61.8 ms; post-TENS: 65 ms). RANGE 67.0– 112.5 The HL of the right calf muscle (pre-TENS: 58 ms; post-TENS: 58.6 ms) MEAN HEIGHT (MALE) 94.55 ± 13.67 and the average HL of the left and right calf muscles (pre-TENS: 59.9 ms; MEAN HEIGHT (FEMALES) 85.30 ± 15.95 post-TENS: 62 ms) were also unchanged (Fig. 2B). 196 D. Logosu et al. I B R O N e u r o s c i e n c e R e p o r t s 11 (2021) 194–199 Fig. 2. Effect of TENS on EMG and MAS parameters. Differences in EMG and MAS scores before (light grey circles) and after (dark grey squares) TENS application were assessed for all participants (n = 15). (A) There was a significant decrease in the H-reflex amplitude of the left calf muscle (p = 0.011), which was not recorded for the right calf muscles (p = 0.08). Nonetheless, a significant decrease was observed when the H-reflex amplitude of both calf muscles was averaged per participant (p = 0.005). (B) TENS had no significant effect on the Maximum H-reflex latency recorded for the left calf muscle (p = 0.427), right calf muscle (p = 0.609) or the average of both calf muscles (p = 0.427). (C) HA Max/Ma Max ratios as calculated before (light grey circles, pre-TENS) and after (dark grey squares, post-TENS) TENS for all participants (n = 15). TENS application did not reveal a significant difference for the left calf muscle (p = 0.691), right calf muscle (p = 0.776) or the average of both calf muscles (p = 0.281). (D) TENS application significantly decreased MAS scores at the left calf muscle (Wilcoxon signed rank test; Z = − 2.598, p = 0.009), right calf muscle (Wilcoxon signed rank test; Z = − 2.889, p = 0.004) and average of both muscle responses (Wilcoxon signed rank test; Z = − 2.887, p = 0.004). HL Max, Maximum H-reflex latency; HA Max/Ma Max, H-reflex amplitude maximum/M-wave amplitude maximum; MAS, Modified Ashworth Scale; TENS, transcutaneous electrical nerve stimulation; EMG, electromyography. We further compared the HA Max/MA Max ratios calculated pre- and 7.5–26.5◦]; p = 0.038) (Table 4). post-TENS application of the left calf muscle (pre-TENS: 0.039; post- TENS: 0.034), right calf muscle (pre-TENS: 0.043; post-TENS: 0.033), 4. Discussion and the average of both muscles (pre-TENS: 0.043; post-TENS: 0.037). There was no significant effect of TENS on the HA Max/MA Max ratios Globally, cerebral palsy affects more males than females, and (Fig. 2C). although we used a small sample size, this elevated male gender sus- Having compared the EMG parameters, we investigated the effect of ceptibility is also reflected in our study (Cleves et al., 2011). Whether TENS on the MAS scores (Fig. 2D). The results indicate that TENS male or female, children with cerebral palsy exhibit preferences for significantly decreased the MAS scores of the left calf muscle from 3.0 specific resting positions. In particular, inactive children exhibited a (IQR: 2.0–4.0) to 2.0 (IQR: 1.0–3.0) (p = 0.009). Although the median preference for the supine position. This can be attributed to the MAS score of the right calf muscle remained unchanged, a decrease in discomfort that is often reported when children are in the prone posi- the range is reported due to a reduction in individual right calf muscle tion, which encourages a flexor pattern. Interestingly, the supine posi- MAS scores and the small sample size (pre-TENS: 3.0 [IQR: 2.0–4.0]; tion has been found to be associated with an increased extensor pattern post-TENS: 3.0 [IQR: 1.0–3.0]; p = 0.004). Overall, the average MAS and can easily introduce a windswept position (Barnes, 1998). scores of both calf muscles decreased from 3.0 (IQR: 1.75–4.0) to 2.5 Although we did not observe a bilateral difference in the MAS scores (IQR: 1.0–3.0) after TENS application (p = 0.004). at baseline, the high MAS score on each side is an indication of muscle Lastly, we compared the dorsiflexion ROM angles recorded pre- and spasticity in both calf muscles and a bilateral brain pathology (Kohan post-TENS. TENS increased the dorsiflexion ROM angles in the left ankle et al., 2010). Additionally, we did not find a correlation between MAS (from 10◦ [IQR: 0–20◦] to 20◦ [IQR: 5–26◦]; p = 0.02), right ankle (from scores and HA Max/MA Max ratios. Unlike the objective nature of EMG, 12◦ [IQR: 2–22◦] to 18◦ [IQR: 10–28◦]; p = 0.003), and average ROM the MAS is entirely based on the examiner’s clinical judgement on the angles for both ankle joints (from 11◦ [IQR: 1.5–20.5◦] to 18◦ [IQR: resistance produced by the muscle being assessed (Bakheit et al., 2003). 197 D. Logosu et al. I B R O N e u r o s c i e n c e R e p o r t s 11 (2021) 194–199 Table 3 After TENS, a decreased HA, which is evidence of a decrease in Individual H-reflex amplitudes scores of the left and right calf muscles. spasticity, was observed although this effect was restricted to the left calf Left Left Status of Right Right Status of muscle. It is accepted that younger age groups elicit lower H-reflex re- pre- post- left post- pre- post- right post- sponses (Palmieri et al., 2004); however, there is conflicting evidence HA HA HA scores HA HA HA scores regarding differences in H-reflex scores between the left and right calf score score score score muscles (Tan, 1985; Jankus et al., 1994; Mezzrane and Kohn, 2002). Participant 0.171 0.146 Reduced 0.099 0.150 Increased Previous studies have reported that TENS is indeed capable of reducing 1 the HA (Hui-Chan and Levin, 1993; Joodaki et al., 2001); however, not Participant 0.063 0.099 Increased 0.143 0.054 Reduced 2 all studies have corroborated this potential benefit of TENS (Gürcan Participant 0.109 0.044 Reduced 0.117 0.117 No change et al., 2015). To the best of our knowledge, our study is the only one to 3 report an effect of TENS in one calf muscle but not in the other. Although Participant 0.251 0.066 Reduced 0.248 0.128 Reduced the children had quadriplegic cerebral palsy, the baseline HA scores lean 4 towards a potential asymmetry. This suggests that the pathology of ce- Participant 0.113 0.130 Increased 0.705 0.225 Reduced 5 rebral palsy in some children may have been asymmetrical to begin Participant 0.323 0.168 Reduced 0.264 0.129 Reduced with. Therefore, this result could explain the asymmetrical effect of 6 TENS. Indeed, asymmetry in brain lesions, even in children with quad- Participant 0.129 0.147 Increased 0.091 0.221 Increased riplegic cerebral palsy, has previously been reported (Abdel-Hamid 7 Participant 0.113 0.108 Reduced 0.121 0.108 Reduced et al., 2018). 8 Despite the effect of TENS on HA, the HL and HA Max/MA Max ratio Participant 0.162 0.098 Reduced 0.097 0.338 Increased remained unchanged. There are reports both in support of (Hui-Chan 9 and Levin, 1993; Gürcan et al., 2015; Garcia and Vargas, 2019) and Participant 0.187 0.070 Reduced 0.227 0.198 Reduced against our findings (Joodaki et al., 2001; Ved and Shah, 2017). 10 Participant 0.687 0.117 Reduced 0.492 0.244 Reduced Therefore, it can be concluded that using EMG measures alone to assess 11 the potential benefit of TENS in reducing spasticity cannot be conclu- Participant 0.248 0.184 Reduced 0.157 0.100 Reduced sive. Underlying factors such as the position and psychological state of 12 the children during data collection could influence study findings. Participant 0.128 0.653 Increased 0.072 0.277 Increased 13 Therefore, interpretation of the EMG results should be performed in Participant 0.220 0.123 Reduced 0.127 0.093 Reduced light of other measures of spasticity such as MAS and ROM. In our study, 14 TENS decreased the MAS and increased the ROM. Both changes are Participant 0.574 0.427 Reduced 0.385 0.337 Reduced indicative of a reduction in spasticity (Seliem et al., 2007; Arati and 15 Shraddha, 2014; Mills and Dossa, 2016). Indeed, mechanisms associated with TENS could lead to a corresponding reduction in spasticity by inhibiting muscle excitability (Mills and Dossa, 2016). The application Table 4 of TENS over a spastic calf muscle will, therefore, result in relaxation of Median differences in ankle dorsiflexion range of motion angles between pre-test the calf muscles, which will in turn ease tension on the ankle joint and and post-test measurements. allow movement. Test limb Pre-test (IQR) Post-test (IQR) Z score P-value This study has some limitations that need to be considered. First, a Left (◦) 10◦ (0–20◦) 20◦ (5–26◦) -2.314 0.02* large sample could not be recruited due to several factors including Right (◦) 12◦ (2–22◦) 18◦ (10–28◦) -2.957 0.003* study site selection, unwilling participation by caregivers of the chil- Average (◦) 11◦ (1.5–20.5◦) 18◦ (7.5–26.5◦) -2.078 0.038* dren, and project cost restraints, which reduced the number of electro- Statistical significance: *p < 0.05. IQR: interquartile range. myography test that could be performed per individual. Second, a single evaluator performed the MAS and ROM assessment. As these are sub- Therefore, it is not surprising that there is no consensus on the rela- jective measures, they could have negatively influenced the reliability of tionship between MAS scores and HA Max/MA Max ratios. (Kohan et al., our findings. To mitigate this, the measurements were conducted twice 2010; Tekgul et al., 2013; Arumugam et al., 2016). Nonetheless, the to reduce the risk of bias. Lastly, the study design and lack of a long-term absence of a correlation could be due to anatomical and biomechanical follow-up on the effect of TENS limits the generalisability of the findings. factors that influence obtained when most ordinal scales are used in Further studies will focus on conducting a multi-centre study to spasticity assessment (Mutlu et al., 2008; Flamand et al., 2013). MAS obtain large samples as well as increase the duration and frequency of scores decreased after TENS, suggesting that in our study population, TENS application over a long-term period. This will not only increase the TENS was capable of decreasing spasticity. power and reliability of the study but also allow us to investigate the Similar to the MAS, there was no significant difference in the base- longevity of any observed benefits. line ROM values between the left and right ankles. It is standard practise for a healthy joint to be used as reference when measuring the ROM of a 5. Conclusion pathological joint (Macedo and Magee, 2008). Since majority of the children in this study presented with spastic quadriplegic cerebral palsy, Challenges related to the management of spasticity among children no meaningful difference in ROM between the left and right ankles was with cerebral palsy require the use of evidence-based interventions. expected. However, we report here a bilateral increase in ROM after Spasticity often employs the use of pharmacological methods, non- TENS application. This supports the MAS findings and lends support to pharmacological methods, and some physical modalities like TENS. our hypothesis that TENS has the beneficial effect of decreasing TENS may be considered as an effective tool for managing spasticity in spasticity. spastic cerebral palsy, considering its ability to reduce neuronal EMG measures were the only objective measures used in this study. A excitability. key indicator of muscle activity is the H-reflex, and it describes the motor neuron excitability (Lebiedowska and Fisk, 2003). At baseline, Acknowledgements there was no significant difference in the H-reflex responses recorded between the left and right calf muscles. We are grateful for all the support received from the workers at the Neurophysiology unit of the Korle-Bu Teaching Hospital. 198 D. Logosu et al. I B R O N e u r o s c i e n c e R e p o r t s 11 (2021) 194–199 Conflicts of Interest Joodaki, M.R., Olyaei, G.R., Bagheri, H., 2001. The effects of electrical nerve stimulation of the lower extremity on H-reflex and F-wave parameters. Electromyogr. Clin. Neurophysiol. 41, 23–28. None. This research did not receive any specific grant from funding Katirji, B., 2016. Clinical electromyography. In: Daroff, R.B., Jankovic, J., Mazzotta, J.C., agencies in the public, commercial, or not-for-profit sectors. Pomeroy, S.L. 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