































 
 

12  Annals of Applied Psychophysiology June 2025 Volume 12 

Exploring the Role of Neuromuscular Electrical Stimulation in 
Neonatal Brachial Plexus Palsy: A Narrative Review of Motor 
Recovery and Functional Outcomes 
Khansa Sheikh1, Shamoon Noushad2, Aqsa Hussain1, Javeria Sheikh1 & Bushra1 Madad Ali 
Malik1 & Basit Ansari1 
1Department of Health, Physical Education, and Sports Sciences, University of Karachi 
2Advance Educational Institute and Research Center 

Corresponding Author: sheikhkhansa99@gmail.com 
Published online: June 2025 

  © The Author(s) 2025 

Abstract 

Objective: This narrative review examines the role of neuromuscular electrical stimulation 
(NMES), particularly reciprocal electrical stimulation (RES), in enhancing motor function 
and limb recovery in infants with neonatal brachial plexus palsy (NBPP).   
Methods: A literature search was conducted from 2021 to 2024 using PubMed, Google 
Scholar, and PEDro, focusing on randomized controlled trials (RCTs) and pilot RCTs. A 
narrative synthesis was employed due to the limited number of eligible studies.   
Results: Three studies met the inclusion criteria. NMES has demonstrated promising 
outcomes in promoting motor recovery and reducing muscle degeneration, with RES showing 
particularly beneficial effects.   
Conclusion: NMES, specifically RES, may be therapeutically valuable in NBPP 
rehabilitation. However, further high-quality and standardized studies are needed to confirm 
these findings.   
 

Keywords: Neonatal brachial plexus palsy, neuromuscular electrical stimulation, reciprocal 
electrical stimulation. 

 
 
 
 
 
 
 
 
 
 

 
 

mailto:sheikhkhansa99@gmail.com


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Introduction 
Weakness or flaccid paralysis of the upper limb identified shortly after birth, known as 

neonatal brachial plexus palsy (NBPP), is caused by damage to one or more nerve roots from 
C5 to T1. The worldwide occurrence of NBPP varies between 0.38 and 5.1 per 1,000 live births, 
with differences observed across regions based on factors such as study location (e.g., 
individual hospitals, specific populations), population-based data, and access to maternal-fetal 
healthcare. NBPP often results in long-lasting consequences and can be a debilitating condition. 
Beyond physical and functional limitations, NBPP can affect family relationships, overall child 
development, and quality of life [1]. 

The brachial plexus consists of a network of peripheral nerves originating from the 
anterior (ventral) rami of the spinal nerves C5-T1. These nerves function as electrical conduits, 
transmitting commands from the brain to the arm muscles and conveying sensory information 
to and from the muscles of the shoulder, elbow, wrist, and hand [2]. Nerve compression or 
strain is the primary cause of brachial plexus injury, although various other factors may 
contribute. Newborns are particularly vulnerable to these injuries during childbirth, with 
specific weakness patterns emerging based on the affected areas of the brachial plexus. The 
most severe form of injury is nerve root avulsion, which leads to complete paralysis of the 
associated muscle. Brachial plexus traction injuries occur when the plexus is excessively 
stretched during delivery, typically related to challenging breech extractions, even in small 
infants, or cephalic presentations in large infants with shoulder dystocia [3].  

The stretching of brachial plexus nerves (C5 to T1) in the perinatal period results in arm 
weakness or paralysis, causing limitations in the active range of motion (AROM) [4]. Although 
not universally present, the application of traction to the neck during difficult deliveries is 
frequently observed in neurological birth injuries, including the aforementioned condition. 
Contrary to the common belief that obstetricians' delivery techniques are solely responsible, 
mismanagement during shoulder dystocia can still cause NBPP [5]. Neonatal brachial plexus 
palsy (NBPP) classification is based on the nature and patterns of nerve damage. The Narakas 
classification system divides NBPP into four categories. 

1. Group I: Classic Erb's Palsy, involving injury to the C5 or C6 nerve roots. This results 
in diminished strength or paralysis, affecting shoulder abduction, external rotation, 
elbow flexion, and forearm supination. 

2. Group II: Extended Erb's Palsy builds upon Group I by including damage to the C5-C7 
nerve roots. In addition to the symptoms observed in Classic Erb's palsy, patients also 
experience a lack of wrist and digital extension. 

3. Group III: Total Palsy without Horner's syndrome, affecting all plexus roots (C5-T1), 
leading to complete flaccid paralysis of the affected limb. However, Horner's syndrome, 
characterized by miosis, ptosis, and ipsilateral facial anhidrosis, was not observed. 

4. Group IV: Total Palsy with Horner's syndrome, the most severe form. This category 
involved all plexus roots (C5-T1) as well as the sympathetic chain. It manifests as 
complete flaccid paralysis of the affected limb, accompanied by Horner's syndrome, 
indicating sympathetic chain involvement and an avulsion injury. Additionally, phrenic 
nerve palsy and elevated ipsilateral hemidiaphragm may be observed. 

The extent and severity of nerve damage influence recovery. Approximately 20%–30% of 
infants experience ongoing impairment in upper limb function and fine motor skills, leading to 



3 
 

difficulties in reaching developmental milestones or facing challenges in self-care and 
instrumental activities of daily living throughout their lives. Some babies undergo initial nerve 
surgery to promote nerve regeneration and muscle reinnervation. The timing of surgical 
intervention varies, but the absence of biceps and shoulder recovery typically indicates the need 
for primary nerve repair. Consequently, restoration of biceps function is generally considered 
the primary focus of NBPP treatment [4]. 

Rehabilitation, including occupational and physical therapy, plays a crucial role in the 
conservative, preoperative, and postoperative management of NBPP [4]. The primary goals of 
therapy include preventing contractures and joint deformities, strengthening muscles while 
maintaining a balance between agonists and antagonists, promoting active movement, and 
improving participation in daily activities in alignment with the International Classification of 
Functioning (ICF) [6]. 

One approach frequently used by therapists is neuromuscular electrical stimulation 
(NMES). This technique employs a handheld, battery-powered device programmed to deliver 
electrical currents through surface electrodes placed on the target muscles. The objective is to 
facilitate improvements in the active range of motion (AROM) and/or muscle strength [4]. 
NMES functions by applying controlled electrical impulses to the affected muscle groups, with 
parameters such as frequency, pulse duration, amplitude, and electrode placement carefully 
selected to optimize therapeutic outcomes. The specific settings, duration of treatment, 
equipment used, electrode positioning, and accompanying therapies can vary significantly [3]. 

Reciprocal electrical stimulation (RES) is a neuromuscular electrical stimulation technique 
that sequentially activates motor units in both agonist and antagonist muscles. This stimulation 
pattern was designed to replicate the natural firing sequence of healthy muscles. Furthermore, 
we hypothesized that RES may enhance the strength of the antispastic muscle while 
simultaneously reducing cortical excitability in the spastic muscle. Additionally, by stimulating 
sensory receptors and neurons within both muscle groups, RES has the potential to increase 
the neural drive and promote improved motor function [2]. 

This review aimed to evaluate the effectiveness of NMES, particularly RES, in the 
management of NBPP. By analyzing the existing literature on NMES application, treatment 
protocols, and patient outcomes, this review aims to determine its role in improving motor 
function, muscle strength, and overall limb function in infants with NBPP.  

 
 
 
 
 
 
 
 
 
 
 
 



4 
 

Methods 

Data Sources and Searches 
An extensive literature analysis was performed to assess the effectiveness of 

Neuromuscular Electrical Stimulation in treating Neonatal Brachial Plexus Palsy. Two 
independent reviewers conducted the search between November 2024 and January 2025. The 
systematic search encompassed three electronic databases: PubMed, Google Scholar, and 
Physiotherapy Evidence Database (PEDro). The study design was limited to RCTs, and only 
English-language publications from 2021 to 2024 were included. To ensure a comprehensive 
search, Boolean operators were employed, combining terms such as Neuromuscular Electrical 
Stimulation OR NMES with Neonatal Brachial Plexus Palsy OR NBPP OR Erb's palsy OR 
infant OR newborn. The inclusion criteria primarily focused on RCTs and pilot RCTs that 
investigated the impact of Neuromuscular Electrical Stimulation on Neonatal Brachial Plexus 
Palsy treatment. The review process adhered to the PRISMA 2020 guidelines for transparency 
and reproducibility. 

The PICO methodology was structured as follows: 

• Population: Infants with confirmed Neonatal Brachial Plexus Palsy (NBPP) 
• Intervention: Neuromuscular Electrical Stimulation (NMES), including RES 
• Comparison: Standard physical or occupational therapy 
• Outcome: Improvements in motor function, muscle strength, and limb functionality 

Study Selection  
The review selection process encompassed a thorough examination of titles and 

abstracts, followed by an evaluation of full-text articles to assess eligibility. The inclusion of 
studies in this comprehensive review was contingent upon meeting the following specific 
criteria: 

Inclusion Criteria:  
• Research studies eligible for inclusion encompassed randomized controlled trials 

(RCTs) or pilot RCTs that investigated the effects of Neuromuscular Electrical 
Stimulation on Neonatal Brachial Plexus Palsy. 

• Eligible studies must have involved participants who were diagnosed with Neonatal 
Brachial Plexus Palsy. 

• Studies have reported outcomes such as improved motor function, muscle strength, and 
overall limb function in infants with NBPP.  

• Studies published in English and available as full-text PDFs were included. 

Exclusion Criteria:  
Studies were excluded based on the following criteria: 

• Non-randomized trials, observational studies, and case reports. 
• Studies focused on conditions other than Neonatal Brachial Plexus Palsy.  
• Research that did not specifically examine the effects of neuromuscular electrical 

stimulation on improving motor function, muscle strength, and overall limb function in 
neonates with brachial plexus palsy.  



5 
 

• Articles that had not undergone peer review or lacked sufficient data for outcome 
analysis. 

• Studies not published in English or not accessible as full-text PDF documents. 

Discrepancies in the study selection were resolved through discussion and consensus. 

Data Extraction 
Data were extracted by two independent reviewers. The collected information 

encompassed study characteristics (author, publication year, and study design), participant 
information (sample size, demographics, and clinical features), and intervention details 
(specifics of Neuromuscular Electrical Stimulation, including treatment frequency and 
duration). The outcome measures included improvements in motor function, muscle strength, 
and overall limb function. The analysis focused on the efficacy of each intervention, 
emphasizing the statistical significance and comparative effectiveness of the key findings. 

Quality Assessment 

The methodological quality and risk of bias of the included studies were assessed using 
two well-established tools: the Cochrane Risk of Bias tool (ROB2) and the Physiotherapy 
Evidence Database (PEDro) Scale. These tools were applied independently to capture both 
internal validity and potential sources of bias. 

Risk of Bias Assessment (ROB2) 

The Cochrane Risk of Bias (ROB2) tool was used to evaluate five key domains: 
randomization process, deviations from intended interventions, missing outcome data, outcome 
measurement, and selection of reported results. Each domain was rated as low risk (✓), high 
risk (X), or some concerns (?), and an overall judgment was made for each study accordingly. 



6 
 

Table 1. Summary of ROB2 Assessment 

Study 
Included 

Bias from the 
Randomization 
Process 

Bias Due to 
Deviations 
from 
Intended 
Intervention 

Bias Due 
to 
Missing 
Outcome 
Data 

Bias in 
Measurement 
of Outcome 

Bias in 
Selection 
of 
Reported 
Results 

Elnegamy, 
T. E. 
(2024) 

? ✓ ✓ X X 

Justice, D. 
et al. 
(2023) 

✓ ✓ ✓ ✓ ✓ 

Abdelaziz, 
E. R. 
(2022) 

? ? ✓ X X 

Legend: 
✓ = Low risk  X = High risk  ? = Some concerns 

• Elnegamy et al. (2024) provided information on dropout rates and blinding, suggesting 
a low risk of bias in some areas. However, the absence of details regarding trial 
registration and concerns in outcome reporting resulted in an overall high risk of bias. 

• Justice et al. (2023) demonstrated methodological rigor across all five ROB2 domains, 
resulting in an overall low risk of bias. 

• Abdelaziz et al. (2022) showed insufficient details regarding the randomization process 
and intervention integrity. Combined with missing information on blinding and registry 
status, the overall judgment for this study was also high risk of bias. 

PEDro Scale Assessment 

To further evaluate methodological rigor, the PEDro Scale was applied. The PEDro 
scale is a validated instrument widely used in physical therapy research to assess randomized 
controlled trials (RCTs) based on 11 criteria—1 addressing external validity (not scored) and 
10 related to internal validity, including random allocation, allocation concealment, blinding, 
and statistical reporting [7,8]. Consistent with common practice in systematic reviews, the 
external validity criterion was not included in the scoring [9]. 



7 
 

Based on PEDro scores, studies were classified as follows: 

• 7–10 = High quality 

• 5–6 = Fair quality 

• ≤4 = Poor quality [10] 

Of the three studies included in this review: 

• One had an existing peer-reviewed PEDro score, which was verified by two 
independent reviewers. 

• The remaining two studies were newly assessed by the same independent reviewers 
using the PEDro scale. 

The consistency and reliability of the PEDro scale for rating clinical trials has been rated as 
excellent to fair, supporting its use in this review [11]. 

 
Table 2. PEDro Scores of Included Studies 

Study Reference 2 3 4 5 6 7 8 9 10 11 Total 
Score 

Study 
Quality 

Tamer Emam 
Elnegamy (2024) 

Y N Y N N Y Y Y Y Y 7 High 

Denise Justice (2023) Y N Y Y Y Y Y N Y Y 8 High 

Emad R. Abdelaziz 
(2022) 

Y N Y N N N Y N Y Y 5 Fair 

Scoring Criteria Key: 

• Y = Criterion satisfied 

• N = Criterion not satisfied 

PEDro Criteria: 

1. Eligibility criteria were specified (not scored) 

2. Subjects were randomly allocated to groups 

3. Allocation was concealed 

4. The groups were similar at baseline regarding key prognostic indicators 

5. There was blinding of all subjects 



8 
 

6. There was blinding of all therapists administering the therapy 

7. There was blinding of all assessors measuring at least one key outcome 

8. Outcome measures were obtained from more than 85% of subjects initially allocated 

9. All subjects received treatment as allocated or were analyzed using intention-to-treat 

10. Between-group statistical comparisons were reported for at least one key outcome 

11. The study provided both point measures and variability measures for at least one key 
outcome 

 

Interpretation of PEDro Scores 

The PEDro scores for the included studies ranged from 5 to 8, with a mean score of 6.67 (SD 
= 1.25), reflecting an overall fair quality across the evidence base. 

• Elnegamy et al. (2024) scored 7/10, indicating high quality. The study fulfilled the 
criteria related to randomization, outcome reporting, and assessor blinding, but did not 
satisfy therapist or subject blinding or allocation concealment. 

• Justice et al. (2023) achieved the highest score (8/10), meeting most of the internal 
validity benchmarks. The only unmet criteria were allocation concealment and subject 
blinding. 

• Abdelaziz et al. (2022) scored 5/10, indicating fair quality. It met fewer methodological 
criteria, lacking subject and therapist blinding, as well as allocation concealment. 

These findings suggest variability in methodological rigor among the studies, with two 
meeting high-quality thresholds and one falling short. Importantly, none of the studies satisfied 
criterion 3 (allocation concealment), which is a critical factor for minimizing selection bias. 

 

Data Synthesis 
Due to the variability in study designs, outcome measures, and intervention protocols, 

a narrative synthesis approach was employed to compare the results of the included studies. 
This synthesis concentrated on the effects of Neuromuscular Electrical Stimulation in 
enhancing motor function, muscle strength, and overall limb function. The synthesis was 
organized based on the quality of the studies, with higher-quality studies given more weight in 
the analysis. When possible, the results were compiled into tables for better clarity. Because of 
the heterogeneity in study designs, outcome measures, and treatment protocols, a meta-analysis 
was not feasible, leading to the adoption of a descriptive approach. 

The PRISMA flow diagram (Figure 1), which describes the study's identification 
procedure, abstract screening results, and full-text eligibility assessments, including the 
rationale for exclusions, was followed for data synthesis. Finally, three articles fulfilled the 
eligibility criteria for full-text evaluation. 

 
 



9 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1. PRISMA 2020 Flow Diagram for Study Selection in this systematic review. 

Results 
The initial screening identified 50 potential studies for inclusion. Upon examining the 

abstracts, only 3 met the specified criteria (Fig. 1). Two of these were randomized controlled 
trials [2,3], while the third was a randomized controlled trial (RCT) pilot study [4]. All three 
studies involved children of both sexes diagnosed with Neonatal Brachial Plexus Palsy. The 
participants exhibited varying symptom durations and ages, ranging from 2 months to 3 years. 
The studies employed six distinct outcome measures, with electromyography being the most 
frequently used [2,3]. These measures have been validated as reliable indicators of clinical 
improvements. The post-intervention follow-up period ranged from immediate to 3 months. 
(Table 2) 

Methodological quality assessment 
(Table 1) displays the PEDro scores of each study. The scores ranged from five to eight, with 
an average of 6.67 (SD 1.25), indicating an overall 'fair' quality of research. Two studies were 
classified as 'high' quality, while one was deemed 'fair' [2,4]. All included studies met five 
PEDro criteria: random allocation, baseline comparability, outcome for >85%, between-group 
statistical comparisons, and reporting of point measures and variability [2,3,4]. None of the 
studies fulfilled criterion three, and only one satisfied criterion five regarding subject blinding 
[4]. 
 

Studies Iden3fied from 
database searching 

(n =300) 

Sc
re

en
in

g 
In

cl
ud

ed
 

El
ig

ib
ili

ty
 

Id
en

-fi
ca

-o
n 

Addi3onal studies iden3fied 
through other sources  

(n = 20) 

Records screened  
(n = 240) 

Records excluded  
(n = 180) 

Full text studies assessed for 
eligibility (n = 50) 

Full-text ar3cles excluded, with reasons (n = 47) 
-Not RCTs  
-No full text 
-Insufficient data 

Studies included in qualita3ve 
synthesis (n = 3) 



10 
 

Analysis 
Table 3: NMES Protocol Summary 

Study NMES 
Type 

Frequency Duration Electrode 
Placement 

Parameters 
Reported? 

Elnegamy et 
al. (2024) 

RES 3x/week 15 mins Elbow muscles Not fully 
reported 

Justice et al. 
(2023) 

NMES Daily 30 mins Not specified Partial 

Abdelaziz et 
al. (2022) 

RES 3x/week Not 
specified 

Not specified Not specified 

 

Table 4: Study characteristics 
Article Control 

Group 
Experimental 
Group 

Sample 
Size 

Frequency Assessment 
post-
intervention 

Follow-
Up 

Key Results 

Elnegamy et 
al. (2024) 

Standard 
Physical 
Therapy 

Standard 
Physical 
Therapy + 15-
minute RES 
(3x/week) 

40 3 times per 
week for 3 
months 

Percentage of 
degeneration 
(RD) with 
electromyogr
aphy & 
TAMS 
(Toronto 
Active 
Motion 
Scale) 

Immediate Significantly 
greater reduction 
in RD and 
increased TAMS 
scores in the study 
group. 

Justice et al. 
(2023) 

Standard 
Therapy  

Standard 
Therapy + 
NMES (30 min 
daily) 

17 30 min daily 
for 3 months 

AROM, 
muscle 
strength, 
morphometri
c 
measurement
s 

1, 2, & 3 
months 

Significant 
improvement in 
elbow flexion 
AROM in the 
NMES group after 
the first month. 
No adverse 
effects. 

Abdelaziz et 
al. (2022) 

A 
specially 
designed 
physical 
therapy 

Same physical 
therapy 
program + 
reciprocal 
electrical 
stimulation 

30 3 
sessions/we
ek for 3 
months 

Percentage of 
degeneration 
(RD) with 
(Electroneuro
graphy) 

Not 
specified 

Improvement in 
functional 
recovery of the 
upper limb in both 
groups, but 
significantly 
greater in the 



11 
 

program 
only 

group receiving 
reciprocal 
electrical 
stimulation. 

 

The included studies examined the efficacy of Neuromuscular Electrical Stimulation (NMES) 
as an adjunctive treatment for infants with neonatal brachial plexus palsy (NBPP) in addition 
to regular physical therapy. The studies varied in terms of their stimulation protocols, outcome 
measures, and follow-up periods. According to all studies, even with some methodological 
differences, infants receiving NMES showed meaningful improvements in functional recovery 
and muscle activation compared to the control groups. 

Table 5. Summary of Reported Effects of NMES and RES in Included Studies 

Study Intervent
ion 

Contr
ol 

Outcome 
Measures 

Effect Reported 
Significa
nce 

Effect 
Direction 

Study 
Qualit
y 
(PEDr
o) 

Elnega
my et 
al. 
(2024) 

RES + 
Standard 
PT 
(3x/week, 
15 min) 

Standa
rd PT 

RD 
(degenerati
on% % via 
EMG), 
TAMS 

Significan
t 
improvem
ent in 
TAMS, 
reduction 
in RD 

Yes 
(statistica
lly 
significan
t) 

Large 
improvem
ent in 
motor 
recovery 

High 
(7/10) 

Justice 
et al. 
(2023) 

NMES + 
Standard 
Therapy 
(30 min 
daily) 

Standa
rd 
Thera
py 

AROM 
(elbow 
flexion), 
muscle 
strength, 
morphometr
ics 

Significan
t 
improvem
ent in 
elbow 
AROM at 
1, 2, and 
3 months 

Yes Moderate 
improvem
ent in 
specific 
motor 
function 

High 
(8/10) 

Abdela
ziz et 
al. 
(2022) 

RES + 
Custom 
PT 
Program 
(3x/week) 

Custo
m PT 
Progra
m 

RD (via 
ENG), 
functional 
recovery 

Greater 
functional 
recovery 
in the 
RES 
group 

Yes Large 
improvem
ent in 
function 
and 
neural 
input 

Fair 
(5/10) 

This table summarizes the clinical effects of Neuromuscular Electrical Stimulation (NMES) 
and Reciprocal Electrical Stimulation (RES) in infants diagnosed with Neonatal Brachial 
Plexus Palsy (NBPP), as reported in the three included studies. It highlights the type of 



12 
 

intervention, sample size, key outcome measures, and direction and magnitude of the observed 
effects. Despite methodological and protocol differences, all studies reported favorable 
outcomes with NMES or RES in improving motor recovery, reducing muscle degeneration, 
and enhancing functional limb use. These findings suggest that NMES, especially RES, may 
offer clinical benefits as a complementary rehabilitation strategy for NBPP. 

 

1. Impact on Muscle Degeneration and Functional Recovery 

Two studies [Elnegamy et al. (2024) and Abdelaziz et al. (2022)] employed electromyography 
(EMG) and electroneurography (ENG) to thoroughly investigate muscle degeneration. 
According to both studies, electrical stimulation resulted in significantly less muscle 
degeneration (RD) in the experimental groups compared to the control groups receiving 
standard therapy. The Elnegamy et al. (2024) study demonstrated a clear improvement 
immediately following the intervention; conversely, the Abdelaziz et al. (2022) study did not 
specify their follow-up duration. Furthermore, Abdelaziz et al. (2022) reported significantly 
greater upper limb functional recovery in a large number of infants who experienced markedly 
improved outcomes with reciprocal electrical stimulation, highlighting its substantial 
advantage over standard physical therapy alone. 

2. Improvement in Active Range of Motion (AROM) and Muscle Strength 

Justice et al. (2023) specifically measured several key AROM parameters, a comprehensive 
range of muscle strength metrics, and various morphometric parameters in a cohort of infants 
who received NMES for 30 minutes each day over a three-month period. One month after the 
intervention, there was a significant improvement in elbow flexion AROM. This improvement 
continued at one, two, and three months of follow-up. The lack of reported adverse effects 
indicates that newborn NMES use is safe and tolerable. 

3. Differences in NMES Protocols and Their Effectiveness 

The studies employed different stimulation parameters. 

• Elnegamy et al. (2024) used 15-minute repetitive electrical stimulation (RES) three 
times per week, demonstrating a significant increase in TAMS (Toronto Active Motion 
Scale) scores and reduced muscle degeneration. 

• Justice et al. (2023) implemented a higher frequency protocol (30 min daily), resulting 
in notable improvements in elbow flexion within a month. 

• Abdelaziz et al. (2022) applied reciprocal electrical stimulation three times per week, 
yielding the greatest functional recovery among the three studies. 

Despite these variations, all three studies concluded that electrical stimulation enhances motor 
recovery and reduces muscle degeneration when used in conjunction with conventional 
physical therapy. 

Discussion 
This review suggests that NMES, particularly RES, may provide potential therapeutic 

benefits for infants with NBPP when used alongside conventional physical therapy. While all 
three studies reported positive trends in motor recovery and muscle preservation, the limited 



13 
 

sample sizes and methodological variability limit the ability to draw definitive conclusions 
from these studies. The studies examined consistently showed that NMES, when used 
alongside traditional physical therapy, improved motor recovery, reduced muscle deterioration, 
and enhanced muscle strength in patients with hemiplegia. NMES achieves these benefits by 
activating both motor and sensory pathways, promoting neuroplasticity, and improving motor 
control and functional recovery. RES, in particular, seems to mimic natural muscle activation 
patterns, potentially leading to more coordinated movements and better motor learning in 
affected infants than TMS. 

A key discovery in this review is the significant reduction in muscle degeneration 
observed in the studies by Elnegamy et al. (2024) and Abdelaziz et al. (2022) Using 
electromyography (EMG) and electroneurography (ENG), these studies provided objective 
evidence that infants receiving NMES experienced less muscle degeneration than those 
undergoing standard therapy alone. The preservation of muscle integrity is crucial for better 
long-term functional outcomes. Additionally, Abdelaziz et al. (2022) reported that infants 
treated with RES showed superior upper limb functional recovery, suggesting that this specific 
NMES technique may be more effective than traditional physical therapy in enhancing 
neuromuscular re-education and muscle recruitment. 

Justice et al. (2023) focused on improvements in active range of motion (AROM) and 
muscle strength, revealing significant gains in elbow flexion AROM that persisted over a three-
month follow-up period. This finding underscores the potential of NMES to produce both 
immediate and lasting functional improvements. The absence of reported adverse effects across 
all studies emphasizes the safety and tolerability of NMES in neonatal populations, which is 
particularly important, given the vulnerability of this age group. This favorable safety profile 
supports the inclusion of NMES in early intervention programs for NBPP, potentially 
accelerating developmental milestones and enhancing the quality of life. 

Despite these promising outcomes, the variation in NMES protocols across studies, 
including differences in stimulation frequency, session duration, and electrode placement, 
makes it challenging to determine the most effective therapeutic regimens. For example, 
Elnegamy et al. (2024) used a protocol with 15-minute RES sessions three times per week, 
whereas Justice et al. (2023) implemented a more intensive daily regimen of 30 min. Both 
approaches yielded positive results, suggesting that NMES can be effective across various 
intensities; however, the optimal parameters for maximizing functional recovery remain 
unclear. Furthermore, the diversity in outcome measures, with some studies focusing on muscle 
strength and others on functional recovery or electrophysiological markers, complicates direct 
comparisons and limits the ability to draw definitive conclusions regarding the most critical 
factors influencing treatment success. 

The included studies demonstrated fair to high methodological quality when evaluated 
using the PEDro scale, suggesting a reasonable degree of robustness in their designs. However, 
potential biases may have been introduced due to certain methodological shortcomings, such 
as inadequate blinding and limited sample sizes, which could have affected the reported results. 
Despite these limitations, the consistently positive outcomes observed across various settings 
and protocols indicate that NMES shows considerable promise as a therapeutic approach for 
NBPP. To advance the field, it is crucial to establish standardized treatment protocols and 



14 
 

outcome measures, enabling better comparisons between studies and facilitating the creation 
of evidence-based clinical guidelines. 

Limitations 
This review provides insightful perspectives on the potential benefits of NMES in 

managing NBPP; however, it is important to acknowledge certain limitations. The small sample 
sizes in the studies reviewed limit the generalizability of the findings to a wider population of 
infants with NBPP. Additionally, the considerable differences in NMES protocols across these 
studies, such as variations in stimulation parameters, session frequency, and treatment duration, 
complicate the development of standardized guidelines and the determination of the most 
effective therapeutic strategies. Furthermore, the predominantly short follow-up periods in 
these studies restrict our understanding of the long-term sustainability of the benefits of NMES. 
While some improvements were noted for up to three months, it remains unclear whether these 
benefits persist into later childhood, when functional demands increase.  

Inadequate blinding in several studies also introduced performance and detection biases. 
These factors highlight the necessity for high-quality, transparent trials. Another limitation was 
the methodological quality of the included studies. Despite fair to high PEDro scores, many 
studies lacked essential elements, such as blinding of participants, therapists, and outcome 
assessors. This lack of blinding may introduce bias, as expectations from both participants and 
researchers could affect the reported outcomes. Moreover, the analysis was based on a small 
number of randomized controlled trials, with only three studies meeting the inclusion criteria, 
which weakened the overall evidence base. The possibility of publication bias should also be 
considered, as studies with positive results are more likely to be published, potentially skewing 
the review findings. 

The risk of bias was considered across studies, particularly regarding potential 
publication bias. The limited number of studies included (n=3) affects generalizability, and 
selective reporting may have skewed the positive outcomes. 

Recommendations for Future Research 
Subsequent investigations should strive to overcome these constraints to bolster 

empirical support for NMES in treating NBPP. Implementing extensive multi-site randomized 
controlled studies would improve the applicability of the results and offer a more thorough 
understanding of the efficacy of NMES across various patient groups. These investigations 
should emphasize methodological excellence by incorporating appropriate randomization, 
allocation concealment, and blinding of subjects, therapists, and outcome evaluators to reduce 
potential biases. Extended follow-up periods are essential to assess the longevity of NMES-
induced benefits and evaluate its influence on functional outcomes as children develop and 
encounter new developmental challenges. 

Furthermore, establishing uniform NMES protocols, including stimulation variables 
such as frequency, intensity, pulse duration, and electrode positioning, would enable better 
study comparisons and aid in identifying the most effective treatment approaches. Future 
research should also delve into the underlying processes by which NMES promotes 
neuroplasticity and functional recovery in patients with NBPP. Comprehending these 
mechanisms could lead to refined therapy protocols and potentially the creation of novel, more 
potent interventions. 



15 
 

Beyond clinical outcomes, upcoming studies should examine the psychosocial effects 
of NMES on both infants and their families, as well as conduct cost-effectiveness evaluations 
to determine its viability for widespread clinical adoption. Comparative research exploring 
NMES alongside or in conjunction with other rehabilitation techniques, such as constraint-
induced movement therapy or mirror therapy, could provide insights into integrated treatment 
strategies that maximize recovery. By addressing these research gaps, future studies can 
contribute to the development of evidence-based guidelines that support the effective and safe 
application of NMES in rehabilitating infants with NBPP. 

Conclusions 

This narrative review suggests that NMES, particularly RES, may benefit motor 
function and reduce muscle degeneration in infants with NBPP. However, the current evidence 
is based on a limited number of small-scale studies that have methodological constraints. 
Future research should emphasize standardized NMES protocols, robust study designs, and 
long-term follow-up to determine the clinical utility of NMES in routine NBPP rehabilitation. 

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