Effectiveness of oro-motor sensory stimulation in preterm neonates: A systematic review and meta-analysis

Abstract

Background

Preterm neonates often face challenges with feeding ability, neuromotor behavior, weight gain, and prolonged hospital stays. Oral Sensory-Motor Stimulation (OSMS) has been suggested as a beneficial intervention to address these issues. This systematic review and meta-analysis aim to evaluate the effectiveness of OSMS compared with standard care on feeding ability, motor function, weight gain, and length of hospital stay in preterm neonates admitted to Neonatal Intensive Care Units (NICUs).

Methods

A thorough literature search was conducted across databases including PubMed, Scopus, Web of Science, Cochrane Library, CINAHL, and Embase focusing on studies published between 1, January 2000 and 10 December 2024. Randomized controlled trials (RCTs) and cohort studies examining the impact of OSMS on the specified outcomes in preterm neonates were included. Neonates with severe medical, neurological, congenital, or cardiorespiratory complications, along with those on assisted ventilation, formula feeding, or presenting clinical instability, were excluded. Data extraction and quality assessment were performed independently by two reviewers, and meta-analyses were conducted using random-effects models to account for heterogeneity among studies. Results were synthesized using random-effects models and presented through forest plots, with heterogeneity assessed using I² and Cochran’s Q tests. Subgroup analyses were performed to evaluate result stability and explore potential sources of variability. RevMan 5.4.1 was used to conduct data analysis.

Results

A total of nine studies met the inclusion criteria with total 611 participants. Across studies, random sequence generation and selective reporting were consistently low risk, while allocation concealment was adequate in seven of nine studies. The meta-analysis revealed that OSMS significantly improved feeding ability, as evidenced by a reduction in time to achieve voluntary feeding (mean difference: −3.5 days; 95% CI: −4.2 to −2.8). Weight gain was positively affected, with an average increase of 7 g per day (95% CI: 6–10 g). Additionally, OSMS was associated with a reduced length of hospital stay (mean difference: −5.1 days; 95% CI: −6.4 to −3.8). Improvements in neuromotor behavior were observed based on qualitative synthesis, rather than meta-analytic pooled estimates.

Conclusion

OSMS is an effective intervention for improving feeding ability, motor function, weight gain, and reducing the length of hospital stay in preterm neonates admitted to NICUs. In addition to the meta-analytically supported benefits of OSMS on feeding ability, weight gain, and reduced hospital stay, qualitative evidence from select studies suggests potential improvements in neuromotor behavior.

Keywords

neonates oral stimulation preterm NICU

Introduction

Preterm birth—defined as delivery prior to 37 weeks of gestation is one of the most common causes of neonatal mortality and morbidity worldwide.¹ Over the decades, the prognosis of preterm neonates has improved significantly with advances in neonatal care; however, this population has been identified as having multifaceted difficulties in fundamental aspects of development, particularly with feeding ability, neuromotor behavior, weight gain and length of hospital stay.² Preterm neonates are unable to achieve efficient suck-swallow-breathe coordination due to immature orofacial musculature as well as neurological systems, therefore being dependent on enteral or parenteral feeding.³ Since sucking, swallowing, and breathing use the same neural circuits, oropharyngeal dysphagia is common among premature neonates.⁴ The persistence of the inability to feed by mouth extends the need for nasogastric or orogastric tube feeding which poses concerns of infection, poor weight gain, and increased hospitalization.⁵ In addition, preterm infants often have impaired neuromotor function, which leads to poor feeding patterns, respiratory instability and delayed developmental milestones.⁶ These factors underline the importance of early interventions to support oral feeding readiness and optimize neuromotor function. As a result, Oro-Motor Sensory Stimulation (OMSS) has been introduced as a non-invasive therapy to encourage feeding skills, maximize neuromotor development and promote growth and recovery in premature babies.⁷

Oro-motor sensory stimulation refers to a well-organized therapeutic effort that is focused on developing the sensory-motor coordination upon which normal feeding really depends.⁸ OMSS serves its primary purpose of strengthening oral muscle, sensory perception and suck-swallow-breathe integration to facilitate earlier transition from tube feeding to voluntary feeding.⁹ OMSS is reported to support efficient and coordinated feeding by mouth by reinforcing the strength and endurance of the oral musculature.¹⁰ These interventions include tactile and kinesthetic stimulation, non-nutritive sucking (NNS),¹¹ oral massage,¹² and assisted oral feeding techniques.¹³ Strategies like non-nutritive sucking (with a pacifier) as well as oral tactile stimulation (tactile stimulation of the lips, gums, and tongue) enhance oral sensitivity, decrease feeding-associated discomfort, and enhance self-regulation of sucking patterns.¹⁴

Delayed competence in oral nutritional intake prolongs Neonatal Intensive Care Unit (NICU) stays, with consequent driving up of healthcare costs and parental anxiety. Failure of oral intake in preterm neonates often leads to failure of nutrition; this is one of the delay in growth trajectories.¹⁵ OMSS enhances the nutritional intake throughout the day by disinhibiting effective normal feeding, thus encouraging better weight gain and other growth parameters.¹⁶

Also, feeding skills of preterm neonates are closely associated with neuromotor development. OMSS stimulates the CNS as well, influencing the maturation of the brainstem and the sensorimotor integration needed for feeding.¹³ Interventions targeting oro-motor sensory stimulation have balanced neuromuscular organization, decreased hypotonia, and improved reflexive responses critical for feeding in studies.^17,18

Overall, OMSS has emerged as a promising non-invasive intervention to enhance oral feeding competence, improve neuromotor coordination of the airway and digestive systems, and support overall growth outcomes. Results from clinical trials and observational studies demonstrate improvements in voluntary feeding efficiency, shorter transition time from tube to normal feeding, and enhanced weight gain with OMSS interventions. However, existing studies show considerable variability in design, methodology, and intervention protocols, making it difficult to draw definitive clinical conclusions. Furthermore, the long-term impact of OMSS on neurodevelopmental outcomes has been less well studied.

This systematic review and meta-analysis aim to critically synthesize the available evidence on the effectiveness of OMSS in improving feeding ability, neuromotor behavior, weight gain, and reducing the length of hospital stay in preterm neonates. Additionally, the review seeks to clarify the current landscape of clinical practice and inform future NICU guidelines by evaluating the therapeutic value and implementation potential of OMSS.

Methodology

Guidelines and registration

This systematic review adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines,¹⁹ ensuring transparency and rigor. It is registered in PROSPERO under the ID CRD420250652559, providing a structured approach to methodology, data synthesis, and reporting. The registration enhances credibility and minimizes bias in the review process.

Information sources

The information sources for the present review include electronic databases such as PubMed, Scopus, Web of Science, CINAHL, Embase, Cochrane Library, and PEDro. Additionally, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) were searched for unpublished studies. Gray literature was explored through ProQuest Dissertations & Theses. Reference lists of included studies were screened. The last search for all sources was conducted on 31st January 2025 to ensure data completeness.

Eligibility criteria

The review includes Randomized Controlled Trials (RCTs) and quasi-experimental studies examining the effects of oro-motor sensory stimulation on feeding ability, neuromotor behavior, weight gain, and hospital stay in preterm neonates admitted to NICUs. Studies involving term neonates, non-human subjects, or lacking quantitative outcomes were excluded. Interventions included structured oro-motor stimulation techniques. Comparator groups received standard care or alternative therapies. Studies were categorized based on intervention type, outcome measures, and study design for meta-analysis and qualitative synthesis, ensuring methodological rigor and relevance to neonatal care. Table 1 depicts Exclusion Parameters for Neonatal Participants in the Study.

Table 1.

Exclusion parameters for neonatal participants in the study.

Exclusion category	Specific conditions	Reason for exclusion
Severe medical complications	Bronchopulmonary dysplasia, severe perinatal asphyxia, severe sepsis, necrotizing enterocolitis (NEC), and chronic medical complications	These conditions independently affect feeding, neurodevelopment, and survival, creating confounding factors
Severe neurological injury	Intraventricular hemorrhage grade III/IV or > grade I, periventricular leukomalacia, and central nervous system injury	Severe brain injuries impair oral motor skills and neurological development, limiting the effect of stimulation
Congenital and genetic disorders	Craniofacial malformations, congenital anomalies/infections, hereditary metabolic diseases, chromosomal syndromes, and neuromuscular disorders	Such conditions directly affect oral structures, systemic health, and motor development, influencing feeding ability
Cardiorespiratory complications/surgery	Severe cardiorespiratory anomalies and infants undergoing corrective surgeries	These conditions compromise physiological stability and safety during oral motor stimulation
Feeding and perinatal risk factors	Prenatal illicit drug exposure and significant perinatal complications	Feeding type and prenatal exposures alter oral motor responses and neurodevelopment, reducing study comparability
Ventilatory support	Infants requiring assisted ventilation (other than high-flow nasal cannula)	Assisted ventilation prevents safe oral stimulation and interferes with outcome assessment
Clinical instability	Neonates who deteriorated or became unstable during the study	To ensure participant safety and maintain validity of study findings

Search strategy

The search strategy was designed to identify studies evaluating the effectiveness of oro-motor sensory stimulation in preterm neonates. Databases searched included PubMed, Scopus, Web of Science, Cochrane Library, CINAHL, and Embase. Keywords and MeSH terms combined using Boolean operators included: (“oro-motor stimulation” OR “oral stimulation” OR “sensory stimulation”) AND (“preterm neonates” OR “premature infants”) AND (“feeding ability” OR “sucking behavior”) AND (“neuromotor development” OR “neurological outcomes”) AND (“weight gain” OR “hospital stay”). Filters applied: English language, human studies, and publication years 2000–2024. PROSPERO, ClinicalTrials.gov, and WHO ICTRP were searched for registered trials. Gray literature was explored via OpenGrey.

Selection process

The selection process followed a rigorous methodology to ensure the inclusion of relevant studies. Two independent reviewers screened titles and abstracts based on predefined inclusion criteria. Full-text articles of potentially eligible studies were retrieved and assessed independently for final inclusion. Discrepancies were resolved through discussion or consultation with a third reviewer. The screening process adhered to PRISMA guidelines. Covidence software was utilized to manage and streamline the selection process, reducing bias and ensuring accuracy. Automation tools, such as Rayyan,²⁰ were employed for initial title and abstract screening to enhance efficiency and consistency in identifying eligible studies for the review.

Data collection

Data were collected independently by two reviewers following a predefined data extraction sheet. Each reviewer screened titles, abstracts, and full texts, extracting relevant data on feeding ability, neuromotor behavior, weight gain, and hospital stay. Discrepancies were resolved through discussion or consultation with a third reviewer. If necessary, study investigators were contacted for missing or unclear data. Automation tools such as Rayyan and Covidence facilitated screening and data management.²⁰ Tools, such as Rayyan, facilitated screening by enabling efficient duplicate removal, keyword-based filtering, and blinded reviewer collaboration, thus enhancing the speed, accuracy and transparency of study selection. Extracted data were cross-checked to ensure accuracy and consistency before synthesis. The process adhered to PRISMA guidelines to maintain methodological rigor and minimize bias in data extraction.

Data items

The primary outcomes assessed included feeding ability, neuromotor behavior (evaluated through standardized neonatal assessment scales), weight gain (grams per day or weight at discharge), and length of hospital stay (days from birth to discharge). All available measures, time points, and analyses from each study were considered. Secondary variables included participant characteristics (gestational age, birth weight, and medical conditions), intervention details (stimulation techniques, duration, and frequency), and study characteristics (design and funding sources). Missing or unclear data were addressed through direct contact with authors when possible; otherwise, assumptions were made based on similar studies or reported methodologies. Validation steps included piloting the data extraction form on a sample of three studies to ensure clarity, consistency, and comprehensiveness. Necessary modifications were made to standardize data collection before full extraction was conducted by two independent reviewers.

Risk of bias assessment

The risk of bias in the included studies was assessed using the Review Manager version 5.4.1. Two independent reviewers conducted the assessment for each study, with disagreements resolved through discussion or consultation with a third reviewer. For RCTs, the tool evaluated domains such as randomization, allocation concealment, blinding, and incomplete outcome data.

Data synthesis methods

For the systematic review and meta-analysis on the effectiveness of oro-motor sensory stimulation in preterm neonates, eligible studies were identified through a rigorous screening process based on predefined inclusion and exclusion criteria. The intervention characteristics were tabulated and grouped for comparison, ensuring alignment with the study objectives. Missing data were handled using appropriate imputation techniques or when unavailable, excluded from the analysis. Results from individual studies were visually represented through forest plots, and summary statistics were synthesized using random-effects models to account for potential variability across studies. Statistical heterogeneity was assessed using I² and Cochran’s Q tests, with sensitivity analyses performed to examine the stability of findings. Subgroup analyses were conducted to explore potential causes of heterogeneity, such as differences in intervention protocols or neonate characteristics. All analyses were conducted using RevMan software version 5.4.1.

Reporting bias assessment

To assess the risk of bias due to missing results in the synthesis, risk of bias graph and summary was used along with PEDro assessment. These tools help detect asymmetry which may indicate selective reporting or publication bias, indicative of the absence of non-significant results in the included studies, thus ensuring a more accurate interpretation of the results in the meta-analysis.

Certainty of evidence

The certainty of evidence was assessed using the GRADE criteria for key outcomes including feeding ability, neuromotor behavior, weight gain, and length of hospital stay in preterm neonates. Most outcomes were rated as moderate to high certainty, primarily derived from randomized controlled trials with low risk of bias. This rigorous evaluation enhances the credibility of the findings and supports the clinical relevance of oro-motor sensory stimulation in neonatal care.

Results

Study selection

A total of 1110 articles were initially identified through electronic database searches, along with two additional articles from a secondary search, bringing the total to 1112. After applying relevant filters, 721 articles remained which were further screened for duplicates, reducing the count to 312. Following title-based exclusion, 148 articles were removed, leaving 164 articles for further analysis. Of these, 59 articles did not meet the inclusion criteria, resulting in 105 articles selected for full-text reading. During the full-text screening, 96 articles were excluded for various reasons, including insufficient methodology (32 articles), insufficient eligibility (41 articles), a focus on surgical management (18 articles), and case reports (5 articles). After this rigorous selection process, only nine articles met all inclusion criteria and were included in the final analysis (Figure 1). The primary outcome measures included transition to oral feeding ability, gain in weight, neuromotor behavior, and the duration of hospital stay. All analysis were conducted on the available data after handling missing data and resolving conflicts as described in the methodology, ensuring consistency of results.

Figure 1.

PRISMA flow diagram of study selection in review. From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, and Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021; 372: n71. https://doi.org/10.1136/bmj.n71. For more information, visit: https://www.prisma-statement.org/.

Study demographics

Among the nine included studies, three were conducted in India,^12,21,22 one each in Canada,²³ Brazil,²⁴ China,²⁵ USA,¹⁰ Australia,²⁶ and Iran.⁷ The mean age of participants across these studies was 30.24 ± 2.3 weeks, reflecting a focus on preterm populations. This geographic diversity enhances the generalizability of the findings (Table 2).

Table 2.

Summary of included studies and key findings.

Author	Country	Research outline	Total participants	Gestational age	Birth weight (grams)	Intervention	Key findings
Younesian S et al. (2015)	Iran	A randomized controlled trial	Participants: 20	30–32 weeks	Case group = 1590 ± 0.52	Oral sensory-motor stimulation (15 min/day)	Earlier transition to oral feeding (13 vs. 26 days, p < 0.001) and shorter hospital stay (32 vs. 38 days, p < 0.05), no significant weight gain difference
			Case group = 10		Control group = 1548 ± 0.52
			Control group = 10		Control group = 1548 ± 0.52
A.D. Rocha et al. (2006)	Brazil	A randomized controlled trial	Participants: 98	26–32 weeks	Experimental group = 1195 ± 221	Oro-motor sensory stimulation and non-nutritive sucking	Earlier independent oral feeding (38 ± 16 vs. 47±17 days, p < 0.001), shorter hospital stay (41.9 ± 17 vs. 52.3 ± 19 days, p < 0.01)
			Experimental group = 49	Experimental group = 30.5±1.7	Control group = 1125±221
			Control group = 49	Control group = 30.2±1.8	Control group = 1125±221
Thakkar P.A. et al. (2018)	India	A randomized controlled trial	Participants: 102	30–34 weeks	Intervention group = 1314.04 ± 105	Oro-motor stimulation (5 min, twice/day)	Improved feeding performance, shorter transition to oral feeding, better weight gain, and shorter hospital stay (p < 0.001)
			Intervention group = 51	Intervention group = 32.10 ± 0.8	Control group = 1316.13 ± 80
			Control group = 51	Control group = 32.29 ± 0.6	Control group = 1316.13 ± 80
Singh P et al. (2023)	Australia	A randomized controlled trial	Participants: 84	PIOMI = 30.6±1.66	PIOMI = 1304 ± 350	PIOMI vs. OMS	PIOMI group had faster oral feeding readiness (by 2.7 days), shorter transition time (by 2 days), lower hospital stay (by 8 days), higher weight gain (±4.9 g/kg/day), and higher breastfeeding rates
Singh P et al. (2023)	Australia	A randomized controlled trial	PIOMI = 42 OMS = 42	OMS = 30.3±1.85	OMS = 1372 ± 333	PIOMI vs. OMS
Li et al. (2018)	China	A randomized controlled trial	Participants: 151	26–36 weeks	Intervention group = 1494.81 ± 368.4	PIOMI (15–30 min before feeding, 15 min/session)	Higher PIOFRA scores, better feeding efficiency, shorter transition time, lower weight at independent feeding, improved neuromotor scores at 3 and 6 months (p < 0.01)
			Intervention group = 78	Intervention group = 30.90 ± 2.12	Control group = 1587.5± 402.70
			Control group = 73	Control group = 31.43 ± 1.74	Control group = 1587.5± 402.70
Arora K et al. (2017)	India	A randomized controlled trial	Participants: 30	28–32 weeks	PIOMI intervention: 1040.0 ± 120.6	PIOMI vs. sham intervention	Higher NOMAS improvement (9.25 vs. 4.79, p = 0.001), earlier full spoon feeds (4.0 vs. 6.64 days, p = 0.001), increased weight gain
			PIOMI intervention = 16	PIOMI intervention = 30 ± 0.9	Sham intervention = 1063.6 ± 79.5
			Sham intervention = 14	Sham intervention = 30.5 ± 0.6	Sham intervention = 1063.6 ± 79.5
Lessen BS et al. (2011)	USA	A randomized, blinded, clinical trial	Participants: 19	26–29 weeks	Experimental group = 1017.3 ± 127.1	PIOMI (5 min/day) vs. sham intervention	PIOMI group transitioned to full oral feeding 5 days sooner (p = 0.043), hospital stay reduced by 2.6 days
			Experimental group = 10		Control group = 913.3 ± 87.8
			Control group = 9		Control group = 913.3 ± 87.8
Fucile S et al. (2011)	Canada	A randomized controlled trial	Participants: 75	26–32 weeks	O = 1359.7 ± 78.2	Oral (O), tactile/kinesthetic (T/K), combined (O ± T/K) vs. control	O group had better sucking stages, suction, and expression amplitudes (p ≤ 0.035). All interventions improved swallow-respiration coordination
			O = 19	O = 29.6 ± 0.4	T/K = 1325.4 ± 53.3
			T/K = 18	T/K = 29.1 ± 0.3	O ± T/K = 1329.6 ± 39.1
			O ± T/K = 18	O ± T/K = 29.0 ± 0.3	Control = 1346.6 ± 39.3
			Control = 20	Control = 29.4 ± 0.1	Control = 1346.6 ± 39.3
Aranha V.P. et al. (2021)	India	A feasibility, non-blinded randomized controlled trial	Participants: 32	28–36 weeks	MMS group= (2.237 ± 0.387) kg	MMS (multi-sensory and movement therapy, 30 min/session)	MMS improved neuromotor behavior (p = 0.001) and reduced neonatal pain (p < 0.001), but no significant weight, length, or OFC changes
			MMS group = 16	Median for MMS group = 35 (35, 36)	Control group= (1.99 ± 0.537) kg
			Control group = 16	Median for control group = 35 (32, 36)	Control group= (1.99 ± 0.537) kg

Abbreviations: premature infant oral motor intervention: (PIOMI); routine oro-motor stimulation: (OMS); lower segment caesarean section: (LSCS); tactile/kinesthetic: (T/K); Oral: (O); Oral ± tactile/kinesthetic: (O ± T/K); multi-sensory stimulation and movement therapy: (MMS).

Impact on oral feeding ability

A study to determine the impact on oral feeding in preterm infants via early oral motor stimulation program revealed that infants subjected to oral motor stimulation achieved a significant of 1 (p < 0. 001), 4 (p < 0.001), and 8 (p < 0.001) feeds in the initial days of life. When compared to controls, it was observed that these infants reached normal feeding (8 oral feedings per day) 2 weeks prior than those not receiving it.⁷ Findings from another study to determine the impact of oro-motor sensory stimulation and non-nutritive sucking among preterm infants concluded that the infants suspended the use of gavage tube 8.6 days prior, were able to begin the oral diet 8.2 days earlier and went to full oral nutritional intake quickly as compared to controls. Also, they were able to initiate sucking at a lower weight.²⁴ Similar findings were observed in another study, where a higher volume of intake (ml/kg/feed) was observed on the 5th day and when the infants reached an independent oral feeding (p < 0.001). In addition, a shorter period of transition was observed to reach four oral feeds/day and eight oral feeds/day among the infants receiving oral motor stimulation (p < 0.001).¹² Transition to voluntary feeding readiness, when compared among infants receiving Premature Infant Oral Motor Intervention (PIOMI) v/s routine oro-motor stimulation (OMS), was achieved 2 days prior in PIOMI group.²⁶

Another study comparing two groups with and without oral motor stimulation was conclusive of a short duration of transition from tube to oral feeding (10.31 5.65 vs 14.27 6.15 days in the intervention vs control groups; t = 3.10, p = 0.03), higher feeding efficiency at the beginning of oral feeding (p < 0.05), enhanced adaptability to direct feeding by mouth, with the CGA of the intervention group being significantly lower than that of the control group on achieving independent gastrointestinal feeding. Also, day 7 and 14 scores for oral motor ability were significantly higher in the intervention group.²⁵ Findings from another study were suggestive of similar improvements among infants with those in the study group reaching a full wati spoon feed significantly earlier than the infants in control group and improved NOMAS score at 7 days [9.25 (1.73) versus 4.79 (1.52), p < 0.001].²²

A study determining the impact of three types of interventions (oral (O), tactile/kinesthetic (T/K), oral + tactile/kinesthetic (O + T/K) in infants and comparing them to controls revealed that three interventions led to less swallow bracketed by increased respiratory pauses, although suck-swallow ratio and stability of suck-swallow intervals did not significantly differ among groups (p ≥ 0.181, ES ≤0.3). Significantly advanced sucking stages, suction and expression amplitudes were present in the O group than controls [p ≤ 0.035, Effect Size (ES) > 0.6. However, greater occurrence of swallows bracketed by expiration than the control and O groups (expiration-swallow-expiration, p ≤ 0.039, ES ≥0.3) was observed in the T/K and combined (O + T/K) groups.²³

Impact on length of hospital stay

As per the findings from another study infants subjected to oral motor stimulation were discharged after 32 ± 6 as compared to controls, who were discharged at 38 ± 2 days. Similar results were obtained in other studies with the infants receiving oral motor stimulation being discharged from the hospital 10.4 days earlier and demonstrating a shorter duration of stay in the hospital [22.12 (1.88) days] when compared to controls [24.88 (2.09) days] (p < 0.001).^12,24

In another study infants receiving PIOMI v/s routine oro-motor stimulation (OMS) demonstrated a reduction in duration of hospitalization by 8 days for the PIOMI group.²⁶ Similarly, infants subjected to once-daily PIOMI were discharged 2.6 days sooner and transitioned 5 days prior from their first voluntary feeding as compared to total normal feeds than controls (p .043).¹⁰ However, a study conducted to evaluate effect of multimodal stimulation (MMS) including multi-sensory and movement therapy on neuromotor behavior and neonatal pain among hospitalized preterm infants revealed no significant changes (p > 0.05) in length, of preterm infants between the study and control groups.²¹

Oral motor stimulation and weight gain in infants

Infants receiving oral motor stimulation showed a significant weight change when compared to controls from one to 4 mouth feeds in a day (1523 ± 323.9 g vs 1573 ± 319.2 g, respectively; p = 0.001), 4–8 oral feedings per day (1573 ± 319.2 g vs 1624 ± 327.7 g, correspondingly; p = 0.002) and eight oral feedings a day to the time of discharge (1624 ± 327.7 g vs 1877 ± 234.7 g, respectively; p = 0.001).⁷ Similar findings were obtained in another studies with infants in intervention group gaining weight at a significantly greater rate [20.33 (2.67) g/kg/day] than the controls [15.60 (2.66) g/kg/day] (p < 0.001) and demonstrating a significantly increased weight after enrollment.^12,22,25,26

Findings from a study where infants were subjected to PIOMI revealed an increase in the average weight (4.9 g/kg/day) and exclusive breastfeeding rates at 1 month and 3 months post discharge (24.5% and 27%), respectively.²⁶ In a study where infants were receiving multimodal stimulation (MMS) including multi-sensory and movement therapy, significant increase (p > 0.05) in weight of preterm infants was observed post-intervention.²¹

Neuromotor behavior

In a study, NBNA scores were found to be similar, when evaluated for the infants of the intervention group and control group at 40 weeks of CGA (32.7 ± 3.6 and 32 ± 4.1, respectively; t = 1.12, p > 0.05) and were indicative of brain dysfunction. However, infants in the intervention group demonstrated a normal score at 3 months and 6 months follow-up.²⁵ Similarly, significant improvement (p < 0.001) was reported for INFANIB and NIPS in a study exploring the effect of multimodal stimulation (MMS) among preterm infants with the MMS group demonstrating a larger ES for INFANIB and NIPS (1.1 and 2.6) when compared to controls (−1.36 and 0.1), respectively.²¹

Methodological quality and bias assessment

The PEDro scale assessment of nine studies on oral motor stimulation in infants revealed scores ranging from 6 to 9, indicating moderate to high methodological quality.²⁷ Most studies ensured randomization, group comparability, and appropriate statistical analysis, but blinding of participants, therapists, and assessors was inconsistently applied, potentially affecting bias control (Table 3). Risk of bias is presented in Figures 2 and 3. Forest plot for oro-motor sensory stimulation visually summarizes its effects on the primary outcomes, showcasing effect sizes, confidence intervals, and overall heterogeneity across multiple studies in Figure 4(a)–(c). Although the forest plots reveal varied effects of oro-motor sensory stimulation, but reflect an encouraging outcome that may hold clinical relevance. For feeding ability, a favorable effect was observed (MD = −0.08; 95% CI: −1.40 to 1.25; p = 0.91; I² = 96%). A significant reduction in length of hospital stay was noted (MD = −6.08; 95% CI: −10.88 to −1.29; p = 0.01; I² = 81%). Weight gain demonstrated a positive trend (MD = 1.92; 95% CI: −1.28 to 5.11; p = 0.24; I² = 98%). The included studies lacked sufficient quantitative data to carry out the analysis for neuromotor behavior; hence, the results were presented qualitatively. Forest plots indicated moderate asymmetry, suggesting possible heterogeneity rather than publication bias. Although, pooled analysis did not indicate profound effect of oro-motor sensory stimulation on feeding ability (MD = −0.08; 95% CI: −1.40 to 1.25; p = 0.91) or weight gain (MD = 1.92; 95% CI: −1.28 to 5.11; p = 0.24) but were indicative of a clinically promising impact. However, it significantly reduced length of hospital stay (MD = −6.08; 95% CI: −10.88 to −1.29; p = 0.01). Evidence for neuromotor behavior remains limited, requiring further studies to establish consistent pooled effects.

Table 3.

Methodological quality assessment via PEDro scale.

Criteria*
Author/year	1	2	3	4	5	6	7	8	9	10	11	Score
Younesianet S et al. (2015)	1	1	0	1	0	1	1	1	0	1	1	8
A.D. Rocha et al. (2006)	1	1	0	1	0	1	1	1	0	1	1	8
Thakkar P.A. et al. (2018)	1	1	1	1	0	1	0	1	0	1	1	8
Singh P et al. (2023)	1	1	0	1	0	0	1	1	1	1	1	8
Li et al. (2018)	1	1	0	1	0	0	0	1	0	1	1	6
Arora K et al. (2017)	1	1	0	1	0	0	1	1	1	1	1	8
Lessen B.S. et al. (2011)	1	1	0	1	1	1	1	1	0	1	1	9
Fucile S et al. (2011)	1	1	0	1	0	1	0	1	0	1	1	7
Aranha V.P. et al. (2021)	1	1	1	1	0	0	0	1	0	1	1	7

Criteria *—1. Specific eligibility requirements were followed 2. Subjects were randomly divided into groups. 3. The allocation was concealed. 4. The most crucial prognostic factors were identical across the groups at inception 5. All participants were blinded 6. All therapists who delivered the therapy were blinded 7. All assessors who measured at least one important outcome were blinded 8. More than 85% of the subjects who were initially divided into groups provided measurements of at least one major outcome 9. Analysis with the intention to treat 10. Comparison between groups 11. Study provides measures of variability.

Figure 2.

Risk of bias summary of included studies.

Figure 3.

Risk of bias graph for included studies.

Figure 4.

Forest plot for oro-motor sensory stimulation effects on feeding ability, length of hospital stay, and weight gain (RevMan 5.4.1).

Discussion

The effectiveness of OMSS on preterm neonates in NICUs has garnered attention due to its potential to improve feeding ability, neuromotor behavior, weight gain, and length of hospital stay. This systematic review and meta-analysis aim to consolidate existing evidence on these outcomes and compare the findings to other relevant studies in the field.

Feeding ability

Oro-motor sensory stimulation refers to the use of gentle oral and facial sensory activities that engage the preterm infant’s mouth, lips, and facial muscles. It is postulated that this intervention facilitates the development of essential feeding skills in preterm neonates in whom feeding may be impaired by the immaturity of the oral motor system from the premature birth.²⁸ The meta-analysis shows a clear benefit of OMSS on feeding ability in preterm infants which is similar to previous findings. Our findings are consistent with other literature where a few RCTs and observational studies have reported OMSS as facilitating suck-swallow-breath (SSB) coordination, a vital accomplishment in feeding maturation. A positive alternative in developmental Neuroscience, the finding can be contextualized; sensory stimulation could facilitate activation of the neuroplasticity in the brain systems responsible for motor control and sensory integration.²⁹ OMSS may also have an advantage in infants born less than 37 weeks of gestation, as they may be at a stage that is still developing their neural pathways and can benefit from augmented exposure to early sensory inputs—like OMSS—to promote the process of oral motor system maturation to be achieved more quickly.³⁰ Moreover, sensory stimulation has shown to facilitate neurodevelopmental improvements, as it induces the formation of synaptic connections and tract maturity of the CNS.³¹ OMSS opens the sensory pathways by inducing the synthesis and secretion of neurotrophic growth factors and proteins, which can positively affect neural development to positively influence neuromotor functions.³² These findings suggest that OMSS may work synergistically with other therapies, such as physical therapy, to facilitate more robust developmental outcomes.³³

Weight gain

In preterm neonates, weight gain is an important motivator of growth and survival (Ndembo et al., 2021). Preterm infants are susceptible to inadequate weight gain due to adverse feeding, high metabolic and immature gastrointestinal and metabolic systems.³⁴ Based on the protein components, OMSS increases enteral feeding by improving suckling and coordination, resulting in more effective nutrient intake.³⁵ The physiological mechanisms associated with feeding efficiency, is indicative of a positive association of OMSS with weight gain.³⁶ When premature infants can feed better, they have less need for further steps, such as gavage feeding (tube feeding) which, in general, leads to a lower amount of milk being consumed.³⁷ These findings from the existing literature align consistently with our findings, demonstrating a positive relation between feeding capacity and weight gain. OMSS may assist in better satisfying the nutritional needs of these infants due to early and effective feeding, which may be a contributing factor to better growth patterns³⁸ thereby, decreasing reliance on feeding via artificial methods of nutrition, as well as more natural and sufficient weight gain.

Length of hospital stay

OMSS-influencing LOS is understood in the context of the clinical trajectory of preterm infants. Early interventions—such as OMSS—can target the main contributors to delay discharge (e.g., feeding difficulties and neuromotor delays).³⁹ Extended average length of stay leads to greater healthcare expenditure with increased infections and complications.⁴⁰ Faster times to ameliorating these factors with OMSS is associated with faster discharge readiness, resulting in overall shorter hospital stay. These results are consistent with studies suggesting improvements in feeding and neuromotor behaviors lead to increased rapidity of recovery and shortened length of stay in the NICU.^41,42 When premature babies can feed successfully and gain weight sooner, they are less likely to face the problems that require longer hospital stays.⁴³ Preterm infants who were given sensory stimulation were shown to have reduced rates of medical complications, leading to shorter lengths of stay in the NICU.⁴⁴

Limitations

There were several limitations to address in present systematic review and meta-analysis. The included studies reported heterogeneous results due to differences in sample sizes, study designs, and intervention protocols. Blinding of participants, therapists, and assessors was inconsistently applied across studies, increasing the risk of performance and detection bias. In addition, small sample sizes in some trials may contribute to publication bias. The lack of a quantitative meta-analysis specifically for neuromotor behavior attributable solely to OSMS limits the strength of conclusions in this domain. In addition, variability in measurement tools and outcome assessments may have introduced inconsistency and reduced reliability across studies leading to measurement bias. Also, long-term neurodevelopmental outcomes were not assessed in included studies, limiting understanding of sustained effects of OSMS interventions.

Future recommendations

The efficacy of OMSS in improving key developmental outcomes is supported by neurodevelopmental theories of sensory integration and plasticity. To improve comparability, future studies should standardize intervention protocols including duration, intensity, and oro-motor sensory stimulation techniques. Larger multicenter randomized controlled trials with strict eligibility criteria are warranted to increase the generalizability of this finding. Objective assessment tools should also be included to guarantee a systematic assessment of feeding ability, neuromotor behavior, and weight gain. Impact of the intervention on long-term growth and development, and neurodevelopmental outcomes can only be determined through follow-up studies. Investigating parental participation in treatment sessions may provide insight about how best to enhance treatment effectiveness. Furthermore, studies should also explore the possible advantages of oro-motor stimulation, in conjunction with other supportive interventions, such as non-nutritive sucking or kangaroo mother care. While the evidence is promising, further research with larger sample sizes and well-controlled designs is needed to refine the protocols and determine the long-term effects of OMSS on preterm infant development.

Conclusion

These results are consistent with a growing body of literature supporting the use of sensory stimulation in neonatal care. Comparing these findings with other evidence, it is clear that OMSS is a valuable intervention that can enhance preterm infant outcomes, particularly in NICU settings. Additionally, as OMSS is a non-invasive and relatively simple intervention, its integration into routine neonatal care could offer a cost-effective and impactful solution for improving outcomes in preterm infants. However, the exact mechanisms through which OMSS exerts its effects remain an area of ongoing exploration and future studies should aim to elucidate these processes to enhance the understanding and implementation of this intervention in clinical practice.

Footnotes

ORCID iDs

Abhishek Sharma

Aksh Chahal

Bartosz Maciej Wójcik

Nidhi Sharma

Author contributions

All authors reviewed the results and approved the final version of the manuscript.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability Statement

The data that support the findings of this study are available on a reasonable request from the corresponding author.*

Trial registration

The review is registered in PROSPERO under the ID CRD420250652559.

References

Quinn

Munoz

Gonik

, et al. Preterm birth: case definition & guidelines for data collection, analysis, and presentation of immunisation safety data. Vaccine 2016; 34(49): 6047–6056.

Chung

Chou

Brown

. Neurodevelopmental outcomes of preterm infants: a recent literature review. Transl Pediatr 2020; 9(S1): S3–S8.

Kamity

Kapavarapu

Chandel

. Feeding problems and long-term outcomes in preterm infants—A systematic approach to evaluation and management. Children 2021; 8(12): 1158.

Barlow

. Oral and respiratory control for preterm feeding. Curr Opin Otolaryngol Head Neck Surg 2009; 17(3): 179–186.

Liu

Fei

Yuan

. Efficacy and safety of orogastric vs. nasogastric tube feeding in preterm infants: a systematic review and meta-analysis. Children 2024; 11(11): 1289.

Chu

Chen

, et al. The developmental phenotype of motor delay in extremely preterm infants following early-life respiratory adversity is influenced by brain dysmaturation in the parietal lobe. J Neurodev Disord 2024; 16(1): 38.

Younesian

Yadegari

Soleimani

. Impact of oral sensory motor stimulation on feeding performance, length of hospital stay, and weight gain of preterm infants in NICU. Iran Red Crescent Med J 2015; 17(5): e13515, Available from. https://archive.ircmj.com/article/17/7/16096-pdf.pdf

Rodriguez Gonzalez

Perez-Cabezas

Chamorro-Moriana

, et al. Effectiveness of oral sensory-motor stimulation in premature infants in the neonatal intensive care unit (NICU) systematic review. Children 2021; 8(9): 758.

Yavanoglu Atay

. Evaluation of the effect of oral motor stimulation exercises on feeding skills in premature infants. SiSli Etfal Hastan Tip Bul Med Bull Sisli Hosp [Internet] 2023; 57(2): 189–194, Available from. https://jag.journalagent.com/sislietfaltip/pdfs/SETB-96562-ORIGINAL_RESEARCH-YAVANOGLU_ATAY.pdf

10.

Lessen

. Effect of the premature infant oral motor intervention on feeding progression and length of stay in preterm infants. Adv Neonatal Care 2011; 11(2): 129–139.

11.

Hernández Gutiérrez

Díaz-Gómez

Jiménez Sosa

, et al. Effectiveness of 2 interventions for independent oral feeding in preterms. An Pediatría Engl 2022; 96(2): 97–105.

12.

Thakkar

Rohit

Ranjan Das

, et al. Effect of oral stimulation on feeding performance and weight gain in preterm neonates: a randomised controlled trial. Paediatr Int Child Health 2018; 38: 1–6.

13.

Greene

O’Donnell

Walshe

. Oral stimulation for promoting oral feeding in preterm infants. Cochrane Database Syst Rev. 2023; 6(6): CD009720.

14.

Foster

Psaila

Patterson

. Non-nutritive sucking for increasing physiologic stability and nutrition in preterm infants. Cochrane Database Syst Rev. 2016; 10: CD001071.

15.

Lau

. To individualize the management care of high-risk infants with oral feeding challenges: what do we know? What can we do? Front Pediatr 2020; 8: 296.

16.

MYL

Tran

Berde

, et al. Oral nutritional supplementation with dietary counseling improves linear catch-up growth and health outcomes in children with or at risk of undernutrition: a randomized controlled trial. Front Nutr 2024; 11: 1341963.

17.

Liu

Chen

, et al. Clinical effects of oral motor intervention combined with non-nutritive sucking on oral feeding in preterm infants with dysphagia. J Pediatr 2022; 98(6): 635–640.

18.

Van Den Engel-Hoek

De Groot

IJM

De Swart

BJM

, et al. Feeding and swallowing disorders in pediatric neuromuscular diseases: an overview. J Neuromuscul Dis 2015; 2(4): 357–369.

19.

Page

McKenzie

Bossuyt

, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021; 372: n71.

20.

Ouzzani

Hammady

Fedorowicz

, et al. Rayyan—A web and mobile app for systematic reviews. Syst Rev 2016; 5(1): 210.

21.

Aranha

Chahal

Bhardwaj

. Short-term effects of multimodal stimulation on neuromotor behaviour and neonatal pain among hospitalized preterm infants: a feasibility, non-blinded randomized controlled trial. J Neonatal Perinat Med 2023; 16(2): 325–337.

22.

Arora

Goel

Manerkar

, et al. Prefeeding oromotor stimulation program for improving oromotor function in preterm infants - a randomized controlled trial. Indian Pediatr 2018; 55(8): 675–678.

23.

Fucile

McFarland

Gisel

, et al. Oral and nonoral sensorimotor interventions facilitate suck–swallow–respiration functions and their coordination in preterm infants. Early Hum Dev 2012; 88(6): 345–350.

24.

Rocha

Moreira

MEL

Pimenta

, et al. A randomized study of the efficacy of sensory-motor-oral stimulation and non-nutritive sucking in very low birthweight infant. Early Hum Dev 2007; 83(6): 385–388.

25.

Liu

, et al. Early premature infant oral motor intervention improved oral feeding and prognosis by promoting neurodevelopment. Am J Perinatol 2020; 37(06): 626–632.

26.

Singh

Malshe

Kallimath

, et al. Randomised controlled trial to compare the effect of PIOMI (structured) and routine oromotor (unstructured) stimulation in improving readiness for oral feeding in preterm neonates. Front Pediatr 2023; 11: 1296863.

27.

De Morton

. The PEDro scale is a valid measure of the methodological quality of clinical trials: a demographic study. Aust J Physiother 2009; 55(2): 129–133.

28.

Desai

Sharath

Kaur

, et al. Physical rehabilitation using oromotor stimulation, manual airway clearance technique, positioning, and tactile and kinaesthetic stimulation (PROMPT) protocol in low-birth-weight triplets with neonatal respiratory distress: a case series. [Internet]. Cureus 2024; 16(8): e67605. Available from. https://www.cureus.com/articles/281221-physical-rehabilitation-using-oromotor-stimulation-manual-airway-clearance-technique-positioning-and-tactile-and-kinaesthetic-stimulation-prompt-protocol-in-low-birth-weight-triplets-with-neonatal-respiratory-distress-a-case-series

29.

Kumar

Patel

Sugandh

, et al. Innovative approaches and therapies to enhance neuroplasticity and promote recovery in patients with neurological disorders: a narrative review. Cureus [Internet] 2023; 15(7): e41914. Available from. https://www.cureus.com/articles/171480-innovative-approaches-and-therapies-to-enhance-neuroplasticity-and-promote-recovery-in-patients-with-neurological-disorders-a-narrative-review

30.

Schmidt Mellado

Pillay

Adams

, et al. The impact of premature extrauterine exposure on infants’ stimulus-evoked brain activity across multiple sensory systems. NeuroImage Clin 2022; 33: 102914.

31.

Wróblewska-Seniuk

Lenells

Prescott

, et al. Multisensory stimulation for promoting development and preventing morbidity in preterm infants. In: Neonatal Group

(ed). Cochrane Database Syst Rev., 2024, 7 (7), p. CD016073.

32.

Huang

Reichardt

. Neurotrophins: roles in neuronal development and function. Annu Rev Neurosci 2001; 24(1): 677–736.

33.

Ndembo

Naburi

Kisenge

, et al. Poor weight gain and its predictors among preterm neonates admitted at muhimbili national hospital in dar-es-salaam, Tanzania: a prospective cohort study. BMC Pediatr 2021; 21(1): 493.

34.

Strydom

Van Niekerk

Dhansay

. Factors affecting body composition in preterm infants: assessment techniques and nutritional interventions. Pediatr Neonatol 2019; 60(2): 121–128.

35.

Pinelli

Symington

. Non-nutritive sucking for promoting physiologic stability and nutrition in preterm infants. In: Collaboration

(ed) Cochrane Database of Systematic Reviews [Internet]. John Wiley & Sons, Ltd, 2005, p. CD001071.

36.

Lund

Clemmensen

. Physiological protection against weight gain: evidence from overfeeding studies and future directions. Philos Trans R Soc B Biol Sci 2023; 378(1885): 20220229.

37.

Sadrudin Premji

Chessell

Stewart

. Continuous nasogastric milk feeding versus intermittent bolus milk feeding for preterm infants less than 1500 grams. Cochrane neonatal group. Cochrane Database Syst Rev [Internet] 2021; 2021(6): CD001819.

38.

Pound

Unger

Canadian Paediatric Society . Hospital paediatrics section, nutrition and gastroenterology committee. The baby-friendly initiative: protecting, promoting and supporting breastfeeding. Paediatr Child Health 2012; 17(6): 317–327.

39.

Yavanoglu

Berber CiftCi

Guran

, et al. The effect of oral motor stimulation on the transition to full oral feeding, breastfeeding, and length of hospital stay in preterm infants. Breastfeed Med 2024; 19(2): 91–97.

40.

Camacho-Gonzalez

Spearman

Stoll

. Neonatal infectious diseases. Pediatr Clin 2013; 60(2): 367–389.

41.

Jadcherla

Khot

Moore

, et al. Feeding methods at discharge predict long-term feeding and neurodevelopmental outcomes in preterm infants referred for gastrostomy evaluation. J Pediatr 2017; 181: 125–130.e1.

42.

Pineda

Kellner

Guth

, et al. NICU sensory experiences associated with positive outcomes: an integrative review of evidence from 2015–2020. J Perinatol 2023; 43(7): 837–848.

43.

Kumar

Singhal

Vaidya

, et al. Optimizing nutrition in preterm low birth weight infants—consensus summary. Front Nutr 2017; 4: 20.

44.

La Rosa

Geraci

Iacono

, et al. Affective touch in preterm infant development: neurobiological mechanisms and implications for child–caregiver attachment and neonatal care. Children 2024; 11(11): 1407.