Keywords
maternal directed - preterm - NICU - physiological parameters - outcome - neonate - behavior
Introduction
The most frequent cause of death in children under the age of five is prematurity. In India, prematurity is a major health concern, with an estimated 3.5 million preterm neonates born each year.[1] According to the United Nations Inter-Agency Group for Child Mortality Estimation (UN IGME) report from 2021, the neonatal mortality rate globally is 17 per 1,000 live births aiming for a neonatal mortality rate of 12 or lower per 1,000 live births by 2030.[2] Small-for-gestational-age babies are a significant burden in low-and middle-income nations, with a concentration in south Asia. To improve survival rates, and lower disability rates, it is urgently necessary to provide effective therapies for infants who are born too small or too soon.[1]
Preterm infants are subjected to stressors in the neonatal intensive care unit (NICU), such as invasive hospital procedures, intense light, and noise from medical equipment.[3] The sounds of the mother's speech or heartbeat and tactile or vestibular stimulation from her movements provide integrated multimodal stimulation to the fetus.[4] The environment's genetic and epigenetic effects, endogenous brain activity, sleep, external events that activate the sense organs, and the physical, chemical, sensory, and social/emotional settings all affect how the brain develops.[5]
The newborn's most crucial responsibility is to adapt to and settle in their new environment, which is very different from their mother's womb. Modern medical technology has improved the chances of survival for preterm infants. However, there are common long-term morbidities. In addition to denying infants the fetal sensory stimulation necessary for their proper development, premature infants are at higher risk of complications such as respiratory distress,[6] learning difficulties, cognitive, sensory, and neurological impairment.[7]
[8]
Early detection of premature babies with potential developmental or mental health issues is important to start interventions immediately since impairments could later emerge.[9] They could need specialized attention in the neonatal critical care unit to help them survive and thrive. Preterm newborns may exhibit positive physiologic and behavioral responses to beneficial NICU interventions.[10] Globally, preterm newborns are more likely to survive thanks to technological and scientific advances that have an impact on their nursing and medical care. Developmental care entails modifying the newborn intensive care unit to lower stress and enhance the preterm neonate's optimal brain and behavioral development. Developmental care is to help each neonate become as stable, structured, and competent as possible by carefully managing them and responding to their cues.[11]
Multisensory stimulation is a well-known strategy to address the issues related to preterm birth-related problems, such as physiological parameters and neuromotor development. The optimum developmental result for the newborn depends on early intervention. Coronavirus disease 2019 (COVID-19) guidelines have limited access to the mothers to NICU and thus limited opportunities for participation in newborn care. Encouragement of mothers in newborn care is vital to facilitate mother-newborn bonding and increase the confidence of mothers in caring for their preemies. Maternal-directed interventions such as skin-to-skin contact, initiating eye to eye contact, singing lullaby, breastfeeding, and emotional support can be beneficial for both the mother and the baby. This study aimed to involve maternal participation in sensory stimulation of their NICU preemies and evaluate its effectiveness on neonatal outcomes.
Materials and Procedures
Research Plan and Participants: A pilot, quasi-experimental study was conducted among the 31 mother preterm newborn dyads in the study and control group from 21/12/2021 to 15/04/2022. Preterm newborns admitted in the premature unit NICU of a tertiary care hospital who met the inclusion criteria after 2 days of stabilization, between 30 to 36 weeks of gestation, weighing between 1 to 2.5kg, and medically stable were selected for the study along with their mothers having no major complications associated with delivery using a purposive sampling technique. The sample size for the main study (from which the pilot sample size was obtained) was calculated by using the formula based on findings of similar research conducted previously[12] with a 0.05 level of significance for the two trials and 0.10 power. A total sample size of 68 each in the experimental and control group was obtained for the main study. However, the authors increased the sample size to 31 each in the pilot study to have a more representative sample size.
The sample in the comparison group received routine care in contrast to the mothers in the trial arm who received training to provide ATVV (Auditory, Tactile, Vestibular, and Visual) stimulation to their preterm newborn in NICU. To avoid selection bias, the sample for the experimental group was chosen last after the data collection was finished on the sample for the control group. The institutional ethical committee approved the study's conduct and informed consent from the participants was received.
The mother in the experimental group was trained to give ATVV stimulation once the mother was comfortable adhering to the stimulation process. Initially, information was given about the procedure using visual aids followed by a demonstration of the procedure using the doll and a return demonstration was taken to ensure that the mother understood the process. The mother was guided to give ATVV stimulation to their preterms in the NICU in the presence of the investigator and after ascertaining the correctness of the procedure, the mother was encouraged to independently carry out the procedure to their preterm neonates.
ATVV stimulation was given by the mothers in the experimental group to their preterm neonates for a total of 12 minutes daily for 10 days. Auditory stimulation included live humming of lullabies throughout the stimulation. After initiating auditory stimulation for 3 minutes, tactile stimulation was given for 3 minutes with warm palms; infant's body is stroked moderately in a sequence of the head, face, chest, upper limbs, abdomen, and lower limbs in a supine position. Following tactile stimulation after a gap of 30 seconds, vestibular stimulation is initiated with slow and steady rocking for 3 minutes. After a gap of 30 seconds, tactile stimulation is repeated for 3 minutes continuing with auditory stimulation. Visual stimulation including eye-to-eye contact was encouraged throughout the stimulation process. During signs of overstimulation, the mother was advised to pause the stimulation for 15 seconds and then continue. The mothers in the control group received a pamphlet explaining the process of ATVV stimulation after the baby was discharged from the NICU.
Measurement: The neonatal outcomes were measured before the intervention as well as 3, 5, 7, and 10 days afterward. Neonatal outcomes measured were (a) physiological indicators (heart, breathing rate, temperature, and oxygen levels in blood) measured using a calibrated multiparameter monitor; (b) the weight of the newborn was measured after changing the diaper using a calibrated weighing machine; (c) behavioral assessment tool for preterm infants was used to assess the behavior of preterm newborn after the mother–newborn interaction in NICU. This tool was used in the Indian setting and permission to use this tool was obtained from the author. No modifications in the tool were done. Two components make up the tool. The autonomic/visceral system has four categories including color, respiration, visceral signs, and neurophysiological responses. The maximum total score for this component is 8. A score of more than 5 to 8 for all the four domains in the subsystem is considered to show “Normal behavioral response” and the scores obtained of 2 to 4 show suspected abnormal behavioral responses and scores of less than 1 show definite abnormal behavioral responses. The component of the state and attention-interaction system consists of three domains: alertness, orientation to an auditory stimulus, and state control. It has a point system scoring, that is, from zero to two for both components. The total score is 6, and scores more than 4 to 6 are considered as “normal behavioral response,” a score between 2 and 4 shows suspected abnormal behavioral response, and scores of less than 1 show “definite abnormal behavioral response.”[13]
The content validity of the tools was ascertained by submitting them to 11 subject experts. The content validity index for baseline characteristics of mother and newborn is 0.98; physiological parameters are 1 as well as preterm behavioral assessment tool is also equal to 1. The intraclass correlation coefficients were used to examine the inter-rater reliability of the behavioral assessment tool for preterm infants. Two independent observers' raw scores for the two subsystems, namely the autonomic and state and attention-interaction systems and their domains in the tool, were calculated using SPSS (Ver. 15.0), South East Asia, Bangalore. The autonomic subsystem's “r” value was 0.96, while the state and attention–interaction subsystem's “r” value was 0.92, indicating good reliability for both of the tool's subsystem.
Data Analysis: SPSS version 23 package was used for data analysis. The data were analyzed using percentages, the frequency for univariate data, standard deviations, and mean in cases of continuous data. The chi-squared test was used to examine categorical variables. Parametric tests utilized the independent t-test. For nonparametric testing comparing independent groups, the Kendall tau-b correlation coefficient was utilized. According to the skewed distribution, one-way analysis of variance (ANOVA) with Bonferroni posthoc was adopted to compare more than two separate groups. Statistical significance was denoted by a p-value less than 0.05
Results
Characteristics of Mother as well as Preterm Newborn
The characteristic data of 31 mothers and preterm newborns in the groups of treatment and control are described in the below text.
According to the information presented in [Table 1], there was not any scientifically significant distinction between the two groups concerning the age of the mothers, the gestational age, or the birth weight of the neonates. The majority of the mothers were primi, homemakers, were from joint families, had a male child, mode of delivery was lower segment cesarean section and were graduated. The occupation of the mother varied significantly across the groups of intervention and control.
Table 1
Demographic characteristics of the mother and preterm newborn, n = 31 + 31
|
Variable
|
Intervention arm
n = 31
|
Control arm
|
t-Value
|
p-Value
|
X2 Value
|
|
Age of mother[a]
|
27.52 ± 3.129
|
27.36 ± 4
|
0.177
|
0.86
|
–
|
|
Gestational age[a]
|
30.81 ± 1.45
|
30.68 ± 1.51
|
0.343
|
0.73
|
|
Birth weight[a]
|
1.60 ± 0.45
|
1.77 ± 0.61
|
1.245
|
0.218
|
|
No. of deliveries (%)
|
|
1
|
23 (74.2)
|
22 (71)
|
–
|
0.6
|
1.022
|
|
2
|
8 (25.8)
|
8 (25.8)
|
|
3
|
0
|
1 (3.2)
|
|
Occupation (%)
|
|
Homemaker
|
21 (67.7)
|
17 (54.8)
|
–
|
0.008b
|
9.684
|
|
Professional
|
5 (16.1)
|
0
|
|
Salaried
|
5 (16.1)
|
14(45.2)
|
|
Type of family (%)
|
|
Nuclear
|
9 (29)
|
10 (32.3)
|
–
|
0.783
|
0.076
|
|
Joint
|
22 (71)
|
21 (67.7)
|
|
Gender of newborn (%)
|
|
Male
|
15 (48.4)
|
20 (64.5)
|
–
|
0.2
|
1.64
|
|
Female
|
16 (51.6)
|
11 (35.5)
|
|
Mode of delivery (%)
|
|
Normal vaginal
|
18 (58.1)
|
11 (39.3)
|
–
|
0.15
|
2.07
|
|
LSCS
|
13 (41.9)
|
17 (60.7)
|
|
Education (%)
|
|
SSLC
|
7 (22.6)
|
4 (12.9)
|
–
|
0.35
|
3.285
|
|
PUC
|
6 (19.4)
|
12(38.7)
|
|
Graduate
|
16 (51.6)
|
14(45.2)
|
|
Postgraduate
|
2 (6.5)
|
1(3.2)
|
Abbreviations: LSCS, lower segment cesarean section; PUC, preuniversity course; SSLC, secondary school leaving certificate.
a Mean ± standard deviation; bHighly significant.
The effectiveness of the maternal-directed intervention on neonatal outcomes is measured in terms of physiological parameters described in [Table 2.] Preterm infant behavioral assessment is described in [Tables 3] and [4].
Table 2
Comparison of temperature in Celsius, heart and respiratory rate per minute, and blood oxygen level in percentage of the preterm newborn, n = 31 + 31
|
Period
|
Physiological parameter
|
Intervention arm
Mean ± SD
|
Control arm
Mean ± SD
|
t-Value
|
p-Value
|
|
Pretest
|
Temperature
|
36.039 ± 0.533
|
36.090 ± 0.591
|
0.381
|
0.719
|
|
Heart rate
|
152.850 ± 13.923
|
152.000 ± 14.708
|
0.152
|
0.853
|
|
Respiratory rate
|
58.871 ± 10.847
|
57.125 ± 10.409
|
0.656
|
0.514
|
|
Oxygen saturation
|
91.097 ± 4.331
|
92.903 ± 2.773
|
1.956
|
0.055
|
|
3rd day
|
Temperature
|
36.116 ± 0.469
|
36.203 ± 0.399
|
0.788
|
0.434
|
|
Heart rate
|
150.380 ± 9.327
|
152.450 ± 8.147
|
0.931
|
0.356
|
|
Respiratory rate
|
57.097 ± 10.143
|
56.321 ± 10.921
|
0.289
|
0.773
|
|
Oxygen saturation
|
93.710 ± 2.224
|
93.645 ± 2.058
|
1.719
|
0.091
|
|
5th day
|
Temperature
|
36.287 ± 0.533
|
36.326 ± 0.565
|
0.278
|
0.782
|
|
Heart rate
|
148.124 ± 7.857
|
151.152 ± 6.202
|
1.684
|
0.097
|
|
Respiratory rate
|
54.290 ± 6.929
|
56.126 ± 8.089
|
0.594
|
0.555
|
|
Oxygen saturation
|
95.774 ± 1.910
|
94.806 ± 1.778
|
0.069
|
0.945
|
|
7th day
|
Temperature
|
36.435 ± 0.376
|
36.339 ± 0.397
|
0.985
|
0.329
|
|
Heart rate
|
146.251 ± 7.762
|
150.845 ± 9.299
|
2.117
|
0.039[a]
|
|
Respiratory rate
|
51.287 ± 6.820
|
55.189 ± 6.925
|
2.178
|
0.0334[a]
|
|
Oxygen saturation
|
96.161 ± 1.828
|
94.355 ± 2.484
|
1.456
|
0.151
|
|
10th day
|
Temperature
|
36.471 ± 0.304
|
36.342 ± 0.362
|
1.520
|
0.134
|
|
Heart rate
|
144.615 ± 9.233
|
150.129 ± 8.940
|
2.889
|
0.009b
|
|
Respiratory rate
|
50.190 ± 5.229
|
55.092 ± 8.520
|
2.619
|
0.01b
|
|
Oxygen saturation
|
96.548 ± 2.158
|
94.484 ± 2.293
|
0.114
|
0.048[a]
|
Abbreviation: SD, standard deviation.
a Significant; bHighly significant.
Table 3
Grading of preterm infant behavior
|
Period
|
Normal behavioral response
|
Suspected abnormal behavioral response
|
Definite abnormal behavioral response
|
|
Frequency
|
Percentage
|
Frequency
|
Percentage
|
Frequency
|
Percentage
|
|
Intervention group: Autonomic/ visceral system
|
|
Pretest
|
15
|
48.4
|
13
|
41.9
|
3
|
9.7
|
|
3rd day
|
21
|
67.7
|
10
|
32.3
|
0
|
0
|
|
5th day
|
24
|
77.4
|
7
|
22.6
|
0
|
0
|
|
7th day
|
30
|
96.8
|
1
|
3.2
|
0
|
0
|
|
10th day
|
31
|
100
|
0
|
0
|
0
|
0
|
|
Control group
|
|
Pretest
|
14
|
45.2
|
14
|
45.2
|
3
|
9.6
|
|
3rd day
|
16
|
51.6
|
13
|
41.9
|
2
|
6.5
|
|
5th day
|
20
|
64.6
|
10
|
32.2
|
1
|
3.2
|
|
7th day
|
22
|
70.9
|
9
|
29.1
|
0
|
0
|
|
10th day
|
24
|
77.4
|
7
|
22.6
|
0
|
0
|
|
State and attention interactive system
|
|
Intervention group
|
|
Pretest
|
2
|
6.5
|
14
|
45.2
|
15
|
48.4
|
|
3rd day
|
10
|
32.3
|
19
|
61.3
|
2
|
6.5
|
|
5th day
|
23
|
74.2
|
8
|
25.8
|
0
|
0
|
|
7th day
|
28
|
90.3
|
3
|
9.7
|
0
|
0
|
|
10th day
|
29
|
93.5
|
2
|
6.5
|
0
|
0
|
|
Control group
|
|
Pretest
|
6
|
16.7
|
7
|
23.3
|
18
|
58.1
|
|
3rd day
|
8
|
25.8
|
14
|
45.2
|
9
|
29.0
|
|
5th day
|
10
|
32.3
|
13
|
41.9
|
8
|
25.8
|
|
7th day
|
12
|
38.7
|
14
|
45.2
|
5
|
16.1
|
|
10th day
|
14
|
45.2
|
14
|
45.2
|
3
|
6.6
|
Table 4
Effectiveness of ATVV stimulation on weight and physiological parameters among the preterm newborns, n = 31 + 31
|
Parameter
|
Intervention arm
|
Control arm
|
|
F-Value
|
p-Value
|
F-Value
|
p-Value
|
|
Weight
|
0.607
|
0.658
|
1.501
|
0.205
|
|
Temperature
|
1.684
|
0.097
|
1.112
|
0.361
|
|
Heart rate
|
3.542
|
0.009[a]
|
2.108
|
0.068
|
|
Respiratory rate
|
3.741
|
0.007[a]
|
2.112
|
0.062
|
|
Oxygen saturation
|
22.651
|
0.000b
|
1.894
|
0.078
|
|
Preterm infant behavior-autonomic/visceral
|
31.674
|
0.000b
|
1.456
|
0.084
|
|
Preterm infant behavior-state regulation
|
49.073
|
0.000b
|
2.451
|
0.058
|
Abbreviation: ATVV, Auditory, Tactile, Vestibular, and Visual.
a Highly significant; bVery highly significant.
The information in [Table 2] shows that the differences in terms of physiological parameters are not statistically significant during the initial period. However, on the 7th and 10th day, the t-value for heart rate, respiratory rate, and oxygen saturation (10th day) is statistically significant (p-value <0.05) indicating that the intervention was effective to lower heart and respiratory rate and higher levels of blood oxygen in the experimental arm thereby accepting the research hypothesis at 0.05 level of significance.
The data in [Table 3] shows the frequency and percentage of each category of preterm infant behavior at different time points for both groups. The intervention group had an increased proportion of normal behavioral responses and decreased proportion of abnormal behavioral responses than the control group in the autonomic/visceral system and state/attention interactive system. The percentage of normal behavioral responses increased over time for the intervention group, while it remained relatively consistent for the control group. Similarly, the percentage of abnormal behavioral responses decreased over time for the intervention group, while it remained relatively consistent for the comparison group.
The effectiveness of maternal directed ATVV stimulation on weight, various physiological parameters, and assessment of preterm infant behavior analyzed using one-way ANOVA is described in [Table 4].
The findings show that neither the intervention group nor the control group's weight or temperature differed significantly; hence, the null hypothesis was accepted. However, in the intervention group, there is a very highly significant rise in oxygen saturation values and a significant lowering of heart rate, respiratory rate, and significant improvement in the normal preterm infant behavior compared with the control group indicating that the difference between the groups is not likely to have happened by chance; hence, the null hypothesis was rejected.
The correlation between the intervention and outcome among the intervention and control group in the areas of preterm assessment behavior was assessed using Kendall tau-b symmetric measures as described in [Table 5] and [Fig. 1]
.
Fig. 1 Comparison of Kendall tau-b value among intervention and control group on Preterm assessment behavior using line graph.
Table 5
Symmetric measures to assess the correlation of the preterm assessment behavior of newborns using Kendall tau-b among intervention and control group
|
Variable/Areas
|
Kendall tau-b value
|
Standard error
|
t-Value
|
p-Value
|
|
Intervention
arm
|
Control arm
|
Intervention
arm
|
Control
arm
|
Intervention
arm
|
Control
arm
|
Intervention
arm
|
Control
arm
|
|
Autonomic/visceral system
|
|
Color
|
0.510
|
0.217
|
0.045
|
0.055
|
8.781
|
1.702
|
<0.001a
|
0.078
|
|
Respiration
|
0.436
|
0.242
|
0.057
|
0.055
|
7.200
|
1.308
|
<0.001a
|
0.125
|
|
Visceral
|
0.502
|
0.145
|
0.052
|
0.045
|
9.106
|
1.801
|
<0.001a
|
0.144
|
|
Neuro
|
0.420
|
0.170
|
0.060
|
0.052
|
6.714
|
1.318
|
0.000b
|
0.154
|
|
State and attention interactive system
|
|
State regulation
|
0.624
|
0.145
|
0.042
|
0.057
|
12.617
|
1.194
|
0.000b
|
0.126
|
|
Orientation to auditory stimulus
|
0.578
|
0.104
|
0.050
|
0.051
|
11.111
|
1.456
|
0.000b
|
0.084
|
|
Alertness
|
0.586
|
0.193
|
0.048
|
0.054
|
11.383
|
1.766
|
0.000b
|
0.062
|
aVery highly significant; bHighly significant.
[Table 5] and [Fig. 1] show that the values of Kendall tau-b for the study group in all areas indicate a moderate positive correlation between the intervention and the outcome with a significance level of 0 to less than 0.001. Hence, the null hypothesis is rejected suggesting that the intervention had a statistically significant effect on the outcome in all areas in the intervention arm, whereas the control arm had a weak positive correlation with no statistically significant outcomes.
Discussion
COVID-19 has restricted the entry of visits in the NICU, causing superimposed stress among parents, lack of support, and opportunity to engage in parenting, which cause them to frequently misinterpret their children's behavioral indicators that can influence the neonatal outcome. Mothers lack knowledge and skill in the care to be provided to the newborn.[14] Adequate maternal guidance and motivation to provide in utero environment and appropriate stimulation can benefit the newborn admitted to NICU facing stress related to it.[15] The many components of supportive care for preterm must be actively taken into account while developing comprehensive developmental support interventions. It is necessary to perform further study to develop initiatives that directly assist families of premature infants.[16] This study aimed to guide the mother in ATVV stimulation of their preterm newborn admitted to NICU and evaluate its effect on their neonatal outcome.
There are professionally directed multisensorial stimulation research studies on preterm but very few parental-directed intervention studies in India. Mothers in this study were guided to give multisensory stimulation to their preterm in NICU. Since the brains of preterm newborns go through a crucial developmental period and maturing during 24 to 40 weeks of gestation, especially during their stay in the intensive care nursery, they are more presumably to have severe short- and long-term consequences on neurodevelopmental deficits. Of all infants, those born before 30 weeks of gestation have the lowest chances for development. These infants stay in the newborn unit of intensive care for a long period, which is not always conducive to brain development and long-term developmental requirements.[17] The newborn included in this study included stable preterm ranging between 30 and 36 weeks of gestation admitted in NICU. ATVV stimulation is a multisensory method of stimulating preterm neonates in the NICU that aims to provide neonates with a range of sensory experiences that will help to promote developmental outcomes. In stable preterm newborns, multisensory stimulation (ATVV) has been demonstrated to be safe.[18]
The results in this study indicate that there is no significant difference between the intervention and control groups in terms of mothers' age (p = 0.73), gestational age (p = 0.73), birth weight (p = 0.218), gender of the newborn (p = 0.2), educational status of the mother (p = 0.35), type of family (p = 0.783), mode of delivery (p = 0.15), and number of delivery (p = 0.6) which indicate that the groups were similar.
This study showed that maternal-directed ATVV stimulation to preterm newborns had no significant differences between the intervention and control groups for weight, temperature, heart rate, respiratory rate, and oxygen saturation at the pretest, 3rd day, and 5th day, However, on the 7th day and 10th day, there were significant differences (p < 0.05) between the two groups for heart rate, respiratory rate, and oxygen saturation (on 10th day) when compared with the control group that had a higher heart, respiratory rate, and lower oxygen saturation. This is thought to be due to the stimulation of the vagus nerve, which helps to regulate the body's physiological functions in preterm neonates, which is important for their overall health and development. This was consistent in study findings where multisensory stimulation led to a decrease in heart rate and respiratory rate,[19] maintenance of oxygen saturation[20] and an increase in weight considerably among the stimulation-led group when compared with standard care[21]
[22] Additionally, premature infants' early postnatal exposure to sounds may improve their ability to process voices.[23] One very relevant stimulation for babies is the mother's voice. In this study mothers in the intervention group were guided to stimulate their preterm newborns by singing lullabies in their own language during their interaction in NICU.
In terms of behavior, ATVV stimulation may improve alertness and attention in preterm neonates. This is thought to be due to the stimulation of the neonate's visual and auditory systems, which can help to promote the development of their cognitive and motor abilities. Additionally, ATVV stimulation may also help to improve the neonate's overall mood and reduce the risk of stress and anxiety. The effectiveness of maternal-directed ATVV stimulation on preterm behavioral assessment in the present study showed that the group receiving treatment had increased percentage of normal behavioral responses and a lower percentage of abnormal behavioral responses compared with the control group. The New Ballard score was used in one study with 80 individuals (treatment: 40; control: 40) to compare the outcomes of a multimodal intervention to standard care. Both groups saw considerable progress both before and after the intervention; however, infants in the experimental group developed their neuromuscular systems more fully than infants in the comparator group (mean difference (MD): 5.60; 95% confidence interval: 4.65–6.55; p = 0.00001).[24] Nurses are trained to identify the cues of stress in newborns, but the mother lacks this knowledge and there is a scarcity of such studies finding the effectiveness of maternal-directed ATVV stimulation on neonatal outcome.
Conclusion
Maternal-directed ATVV stimulation is a promising method for promoting the developmental outcomes of preterm neonates in the intensive care nursery. It can have early positive effects on the physiological parameters and behavior of preterm newborns. However, more research is needed to fully understand the long-term effects of maternal-directed ATVV stimulation on preterm neonates and to determine the most effective methods of implementation.
