Two codes in the Fogel Scoring System (Fogel, 2000
) were not used in the analysis because they occurred too infrequently to analyze: Disruptive behavior was noted for less than 20 seconds in 8 dyads pre neutral face, and in 4 dyads post neutral face. The occurrence of disruptive behavior was similar among groups. Unengaged behavior was not observed.
To assess the quality of infant affect in the kangaroo group during dyad reunion (phase c), the proportion of infant positive behavior (smiling, laughing, reaching for mother) was examined. Infants in the kangaroo group spent 28.5% (± 23.7) of the 2-minute reunion displaying positive behaviors, compared to 9.6% (±10.9) in the blanket group, and 21.8% (± 24.8) in the control group. A nonparametric analysis, Kruskal-Wallis, used because of unequal variances, showed a difference among groups, X2 (2, N = 64) = 7.88, p = .019).
Hypothesis #2, Neutral Face Infant Vitality
During phase (b), neutral face, positive and negative vitality can be evaluated as the infant bids for maternal attention. Positive and negative vitality was compared between groups using MANCOVA with maternal depression and infant sex as covariates. No difference was found (Pillai’s Trace (F (2,62) = 1.13, p = .345) between groups. shows the group percentages of positive infant behavior and negative protest during the 2-minute neutral face.
Comparison of Group Meansa for Infant Behavior During Still Face Period by MANCOVA
Hypothesis 1, that at six months of age (4 months corrected age): mother-infant dyads who experienced daily kangaroo holding for 8 weeks would show more co-regulated responses during play during a standard still-face procedure than dyads who experienced blanket holding or were in the control group, was partially supported by results of this study. Dyads who experienced kangaroo holding an average of one hour per day for 8 weeks did not display differences in co-regulatory interaction before the maternal neutral face but did display more symmetrical, and less asymmetrical interaction in the reunion phase, after stress of the neutral face. Hypothesis two, that infants who experienced kangaroo holding for 8 weeks would show greater vitality in their efforts to re-engage mothers during the still-face portion of a standard still-face procedure than infants who experienced blanket holding or were in the control group, was not supported.
Both symmetrical and asymmetrical interactions are considered co-regulatory, but symmetrical co-regulation is described by Fogel & Garvey (2007)
as communication that is mutually engaging. Mother and infant movements flow continuously with neither one as initiator or follower, yielding co-created, novel information that was not available to the dyad before this interaction (Fogel & Garvey, 2007
). Mutual unity observed during symmetrical interaction differs from more passive infant contribution in asymmetrical interaction, suggesting a higher level or more optimal co-regulation in symmetrical than asymmetrical interaction. No differences in symmetrical or asymmetrical co-regulation were found among groups in the pre neutral face portion of the observation. Mothers played with their infants, but could not touch them. The findings indicate that in a relatively low stress play activity, neither type of holding nor the intervention used in this study influenced co-regulatory interaction.
Differences among groups in this study were found in the reunion phase or phase (c) post neutral face period. The kangaroo group demonstrated more symmetrical behavior than the other two groups. The blanket holding and the control groups were similar in demographics and holding practices. The only difference was the structured home visiting intervention received by the blanket holding group. Structured home visiting was an intervention for the nurse supported holding groups, but apparently not an effective one. If it had been effective, the blanket group would have been more similar to the kangaroo group, not the control group. However, as Anderson (2003) reported, some intervention is needed to promote kangaroo holding. Findings in this study that mothers in the control group, who were unsupported in their holding choice primarily chose blanket holding support Anderson’s opinion.
The reunion phase of the observation is challenging for the dyad as both members attempt to repair the mismatches that occurred during the neutral face phase, and infants may continue to display residual distressed behaviors (Moore & Calkins, 2004
; Weinberg & Tronick, 1996
). Either positive or negative interaction may be symmetrical, but it may be easier for the dyad to re-establish symmetry when both members display positive affect. In this study, infants in the kangaroo group displayed more positive behavior than infants in the other two groups after the stress of the neutral face. Their ability to arouse to meet the mother’s positive affect and to contribute to the interaction by actively smiling and vocalizing suggests that they were more self-regulated than the other infants. The enhanced self-regulation may be due to physiologic regulation that was assisted by kangaroo holding and reported by others (Bergman et al., 2004
; Fohe, et al., 2000
Mothers in the kangaroo group had higher levels of depression at the time of study enrollment than the other two groups. Depression has been reported to interfere with quality of mother-infant interaction (Lindberg & Ohrling, 2008
; Shaw et al., 2009
). Our results suggest that the combined effects of nursing support and kangaroo holding on symmetrical co-regulation overrode the potential negative effects of maternal depression. Feldman et al. (2003)
suggested that the close contact experienced by mothers and infants during kangaroo holding improves symmetry in the relationship. Symmetry that forms in the early weeks of life seems to permeate the relationship several months later. This is especially important with high-risk groups such as dyads in which the infant was born preterm (Amankwaa et al., 2007
; Cornish et al., 2006
; Forcada-Guex et al., 2006
; Holditch-Davis et al., 2007
) for whom supportive interventions are particularly needed.
Because history/experience in the relationship contributes to the repair of mismatches (Kalinauskiene et al., 2009
), results of this study suggest that dyads who were kangaroo holding developed a positive way to repair mismatches. The neutral face is a novel experience for most dyads and mothers and infants in the kangaroo group responded to this novelty with co-regulatory skills that allowed them to have a rewarding experience even after the stress of the neutral face episode.
Findings from two other longitudinal studies addressing mother-infant interaction in dyads who practiced kangaroo holding have been reported (Chiu & Anderson, 2009
; Feldman et al., 2002
). Feldman et al. (2002)
who compared blanket holding under “standard care” conditions to supported kangaroo holding, found that during a low stress play interaction mothers who had practiced kangaroo group were more sensitive than mothers who had practiced blanket holding, but infants behaved similarly in the two groups. The infant sample in the Feldman et al. (2009) study was very similar to the current study sample. In the current study, interactions did not differ among groups during the low stress play episode prior to the neutral face condition, similar to the report by Feldman and colleagues (2002)
. However, infants and dyads who were supported in kangaroo holding showed more optimal interaction during the higher stress reunion phase. Findings suggest that kangaroo holding may foster resilience in the dyadic relationship to manage stress or novelty with ease.
Chiu and Anderson (2009)
in a randomized controlled trial also examined mother-infant dyads when preterm infants were six months of age. Dyads practicing kangaroo holding were compared to dyads receiving “routine” care who practiced blanket holding. Dyads were encouraged and supported to begin kangaroo holding within the first 42 hours after birth and practiced kangaroo holding for at least one hour a day over a 5-day period. In structured feeding and teaching observations during which maternal sensitivity to infant cues, response to distress and social-emotional and cognitive growth fostering were assessed, Chiu and Anderson found comparable maternal scores at six months between the two groups. The infant score components of the observations were clarity of cues and response to mother. Infants who received kangaroo holding, showed significantly lower scores than infants who received blanket holding. These results contrast with those of the current study in which dyads who practiced kangaroo holding were more mutual partners during interaction than dyads practicing blanket holding. In the current study, dyads practiced kangaroo holding for 8 weeks. Differences in findings might be due to the extended kangaroo holding period in the current study.
Unilateral interactions reflect un-coordinated behavior. One member of the dyad is self-occupied and the other is trying to engage that member in a dual interaction. No differences among groups were found in unilateral interaction in this study. Moderate, not high levels of coordinated behavior are associated with the most optimal outcomes in the mother-infant relationship so unilateral interaction is important in the dyadic interface (Jaffe et al., 2001
). Interaction stimulates infants so they often use gaze aversion or turning away to stop interacting and regulate themselves (Sumner & Speitz, 1994
). Infants in this study spent approximately one-third of the observation in unilateral interaction, which is similar to the amount reported in a study of 3 to 4 month-old infants born at term (Moreno et al., 2006
). The infrequency of occurrence of disruptive and unengaged behavior in mother-infant dyads has been found in other studies (Evans & Porter, 2009
Loss of 25% of the sample for this 6-month assessment should be considered when assessing results of this study. In order to adequately compare holding practices of the three groups, mothers were asked to self-report amount and type of holding using diaries that were collected and monitored weekly. This necessitated a brief description of kangaroo holding to the control group. Maintaining a diary focused on holding may have increased the amount of holding done in the control group, but it did not appear to influence their type of holding. Most mothers in the control group chose the blanket method. Direct observation or videotaping holding would be more exact than maternal self-report but not practical for more than brief episodes. Two coders for the Still Face were not blind to the hypotheses of the study which is a potential source of bias, although two additional coders who were blinded to the hypotheses and group assignment were added for the co-regulation coding.
Future research focused on the time of initiation and duration of holding will be helpful in establishing optimal dosage of kangaroo holding. Feldman et al (2002)
found superiority in dyadic interaction after at least 2 weeks of daily kangaroo holding between kangaroo dyads and a blanket holding comparison group, but holding was not randomly assigned. Chiu and Anderson did not find differences in infant behavior after 5 days of kangaroo holding suggesting that more time might be needed. Neither study examined holding practices after discharge, so it is unknown what holding practices were at home. Longitudinal research spanning several years may show continued benefits for preterm infants when compared to blanket holding.
Many mothers may not appreciate being influenced to adopt a particular holding method, as evidenced by the high rate of refusal to participate in this study. Yet, some encouragement seems necessary for mothers who may be interested in the method but need more than information to adopt kangaroo holding. Mothers in the control group in this study had knowledge of the kangaroo method, but without support, most did not try it or used it minimally. When preterm infants are hospitalized, nurses can educate and provide support and encouragement to mothers to hold kangaroo style. Information that the method can also be used at home and suggestions for implementation at home, may prolong the experience for some mothers. The potential of enhanced infant regulation and more rewarding interactional experiences are benefits that nurses can include when discussing kangaroo holding.