Neonatal Handling Affects Durably Bonding and Social Development

The neonatal period in humans and in most mammals is characterized by intense mother-young interactions favoring pair bonding and the adaptation of neonates to their new environment. However, in many post-delivery procedures, human babies commonly experience combined maternal separation and intense handling for about one hour post-birth. Currently, the effects of such disturbances on later attachment and on the development of newborns are still debated: clearly, further investigations are required. As animals present good models for controlled experimentation, we chose domestic horses to investigate this issue. Horses, like humans, are characterized by single births, long lactating periods and selective mother-infant bonds. Routine postnatal procedures for foals, as for human babies, also involve intense handling and maternal separation. In the present study, we monitored the behavior of foals from early stages of development to “adolescence”, in a normal ecological context (social groups with adults and peers). Experimental foals, separated from their mothers and handled for only 1 hour post-birth, were compared to control foals, left undisturbed after birth. Our results revealed short- and long-term effects of this unique neonatal experience on attachment and subsequent social competences. Thus, experimental foals presented patterns of insecure attachment to their mothers (strong dependence on their mothers, little play) and impaired social competences (social withdrawal, aggressiveness) at all ages. We discuss these results in terms of mother-young interactions, timing of interactions and relationships between bonding and subsequent social competences. Our results indicate that this ungulate species could become an interesting animal model. To our knowledge, this is the first clear demonstration that intervention just after birth affects bonding and subsequent social competences (at least until “adolescence”). It opens new research directions for studies on both humans and other animals

The unsupported upper limb exercise test in people without disabilities: assessing the within-day test–retest reliability and the effects of age and gender

Purpose: To estimate the within-day test–retest reliability and standard error of measurement (SEM) of the unsupported upper limb exercise test (UULEX) in adults without disabilities and to determine the effects of age and gender on performance of the UULEX. Method: A cross-sectional study was conducted with 100 adults without disabilities (44 men, mean age 44.2 [SD 26] y; 56 women, mean age 38.1 [SD 24.1] y). Participants performed three UULEX tests to establish within-day reliability, measured using an intra-class correlation coefficient (ICC) model 2 (two-way random effects) with a single rater (ICC[2,1]) and SEM. The effects of age and gender were examined using two-factor mixed-design analysis of variance (ANOVA) and one-way repeated-measures ANOVA. For analysis purposes, four sub-groups were created: younger adults, older adults, men, and women. Results: Excellent within-day reliability and a small SEM were found in the four sub-groups (younger adults: ICC[2,1]=0.88; 95% CI: 0.82, 0.92; SEM∼40 s; older adults: ICC[2,1]=0.82; 95% CI: 0.72, 0.90; SEM∼50 s; men: ICC[2,1]=0.93; 95% CI: 0.88, 0.96; SEM∼30 s; women: ICC[2,1]=0.85; 95% CI: 0.78, 0.91; SEM∼45 s). Younger adults took, on average, 308.24 seconds longer than older adults to perform the test; older adults performed significantly better on the third test (p0.05). Conclusion: The within-day test–retest reliability and SEM values of the UULEX may be used to define the magnitude of the error obtained with repeated measures. One UULEX test seems to be adequate for younger adults to achieve reliable results, whereas three tests seem to be needed for older adults.Objectif : évaluer la fiabilité d'un test-retest en une même journée et l'erreur type de mesure (ETM) du test d'exercice des membres supérieurs sans appui (UULEX) chez des adultes sans incapacités et déterminer les effets de l'âge et du sexe sur leur exécution. Méthodologie : les chercheurs ont réalisé une étude transversale auprès de 100 adultes sans incapacités (44 hommes, d'un âge moyen de 44,2 ans [ÉT 26], et 56 femmes, d'un âge moyen de 38,1 ans [ÉT 24,1]). Les participants ont effectué trois UULEX pour établir la fiabilité du test-retest en une même journée, mesurés à l'aide du modèle 2 de coefficient de corrélation intraclasse (ICC, effets aléatoires bilatéraux) comportant un ICC(2,1) et une ETM à un seul évaluateur. Les chercheurs ont examiné les effets de l'âge et du sexe à l'aide d'une analyse de variance bifactorielle à mesures mixtes et d'une analyse de variance unifactorielle à mesures répétées. Pour les besoins de l'analyse, les chercheurs ont créé quatre sous-groupes: jeunes adultes, adultes plus âgés, hommes et femmes. Résultats : les quatre sous-groupes affichaient une excellente fiabilité en une même journée et une petite ETM (jeunes adultes: ICC[2,1]=0,88 [IC 95% : 0,82, 0,92] et ETM∼40 secondes; adultes plus âgés : ICC[2,1]=0,82 [IC 95 % : 0,72, 0,90] et ETM∼50 secondes; hommes: ICC[2,1]=0,93 [IC 95% : 0,88, 0,96] et ETM∼30 secondes; femmes: ICC[2,1]=0,85 [IC 95 % : 0,78, 0,91] et ETM∼45 secondes). En moyenne, les jeunes adultes ont effectué le test pendant 308,24 secondes de plus que les adultes plus âgés; ceux-ci ont obtenu un résultat nettement meilleur au troisième test (p0,05). Conclusion : il est possible d'utiliser la fiabilité de test-retest en une même journée et les valeurs d'ETM de l'UULEX pour définir l'importance de l'erreur obtenue lors de mesures répétées. Un UULEX semble suffire pour que les jeunes adultes obtiennent des résultats fiables, tandis que trois tests semblent nécessaires chez les adultes plus âgés