Short-duration training improves babies’ manual dexterity

Early intervention may prevent problems in the motor and cognitive development of preterm infants and those with Down’s syndrome or neurological conditions such as cerebral palsy or myelomeningocele.

By Karina Toledo*

Agência FAPESP – A simple, short-duration training protocol developed at the Federal University of São Carlos (UFSCar) may help typical and atypical infants between the ages of 3 and 5 months develop their reaching ability (to extend their arms until their hands touch an object, with or without grabbing it).

According to the researchers, this type of intervention could prevent problems in the motor and cognitive development of premature infants and of infants with Down’s syndrome, cerebral palsy or myelomeningocele (spina bifida).

“Manual reaching is essential, allowing infants to acquire manipulative abilities such as grabbing and exploring a toy or food, supporting themselves on furniture and standing. It is through this exploration of objects and space, by perceiving the texture, weight and malleability or rigidity of an object, that infants are able to form concepts. A delay in developing manual dexterity could result in problems during the pre-school years, such as difficulty in holding a pencil, understanding or drawing shapes and calculating how much strength is needed to handle an object,” explained Eloisa Tudella, a researcher at the Center for Biological and Health Sciences (CCBS) at UFSCar.

Tudella is coordinating the project “The influence of specific training on reaching in full-term and preterm infants,” funded by FAPESP and by the Maria Cecília Souto Vidigal Foundation (FMCSV) under a cooperative agreement between the two institutions. Partial findings were presented on March 13 at the 1st Child Development Research Conference held at FAPESP.

“The technique used in the study was developed in practice during the patient care that we administered through the program of early intervention offered by the Center for Neuropediatric and Motor Studies (Nenem) at UFSCar. We decided to take this methodology into the laboratory to determine the effectiveness of what we were seeing clinically,” Tudella explained.

Until now, the research has been conducted by three doctoral students. Andréa Baraldi Cunha, an FAPESP grant recipient, assessed the effect that training had under varied practice conditions on 30 full-term infants (i.e., born between 37 weeks and 41 weeks and 6 days).

Another FAPESP grant recipient, Daniele de Almeida Soares, evaluated the effect of training under blocked schedule practice conditions on 36 late-preterm infants (i.e., born between 34 weeks and 36 weeks and 6 days).

The effects of the training were also determined in 18 extremely premature infants (i.e., born at 33 weeks or earlier) during the doctoral studies of Elaine Leonezi Guimarães.

The researchers explained what manual reaching was to the mothers and asked them to pay attention to when their infants began to demonstrate this type of movement. “We called the parents when the infants were about two months old. In addition to that, we made weekly visits, once or twice per week, to check the onset of reaching. Once it was determined that the infants had begun manual reaching, they were brought into the laboratory,” Tudella explained.

The full-term infants demonstrated their first movements when they were 14 weeks old, on average. The average for the preterm infants was 16 weeks. “Although the preterm babies demonstrated no delay in gross motor skills, such as controlling their head and trunk, there appeared to be a delay in fine motor skills. Perhaps the infant had tried to pick up an object, was unable to, became frustrated and gave up. Over time, this developmental deficit builds up, and as the infant gets older the problem becomes bigger than what was observed at four months of age. We want to keep that from happening,” Tudella said.

According to Guimarães, when the age of the premature infants is adjusted using the expected date of birth, it can be noted that these infants begin reaching during the appropriate period but that the quality of the movement is inferior. “The movements are not as fluid, and the hand position is not the most appropriate. We don’t know whether they are going to recover on their own through environmental stimulation, but why wait to see what happens if we can anticipate problems and stimulate more skilled reaching?” she asked.

Training

In the studies, the infants were divided into two or three groups. One or two of the groups underwent an intervention, and the other group received only “social training”; in other words, the infants interacted with the researchers, but there was no encouragement by guiding their arms.

The training can be conducted by a therapist or by the infant’s mother. The infant should be positioned in the lap or in a baby chair reclined 45° to encourage manual reaching and to enable the infant to see objects. Each object needs to be light and malleable to facilitate grabbing, and it should be placed in the infant’s field of vision. It is expected that the infant will perceive the object and attempt to reach for it.

The training protocol presented by the researchers includes three activities. The first consists of placing the object in the field of vision and leading the infant’s hand to the object.

The second activity consists of positioning the infant’s hand in her field of vision so that she can touch the object. If the infant does not touch the object, tactile stimulation should be induced using the infant’s own hand to encourage the act of touching and grabbing the object.

In the third activity, the infant’s arms should be positioned alongside her body. Tactile stimulation is then induced by touching the toy to the baby’s arm, wrist and hand. The toy should be at the infant’s midline so that she can reach it. The infant is expected to extend their arm in the direction of the object and to touch it.

“The object needs to be placed at the infant’s midline, within reaching distance. The training should be short because infants in this age range tire easily. Therefore, it should be repeated several times per day. The training time in our studies was four to five minutes, with different numbers of repetitions. We’re still studying the ideal training intensity for achieving the best results, but it appears that training that involved more repetition was most effective,” Tudella explained.

The infants were assessed before and after training. In the group of full-term infants, there were two days of four-minute sessions, three times per day. The group of late-preterm infants underwent one four-minute session, and the extremely preterm infants underwent one five-minute session.

The training sessions were recorded, and afterwards the researchers analyzed the following qualitative variables: whether reaching occurred with one or two hands; whether the hand was in a horizontal, oblique or vertical position; whether the hand was open or closed; and whether the object was touched with the back of the hand or the palm.

Kinematic variables (the duration and speed of movement, the rate of accuracy, the rate of deceleration and the number of corrections in the infant’s movement) were also assessed.

“The position of the hand should change depending on the object and how it is presented. The infant has to learn how to grab onto the object. The infant also needs to slow her movement down as her hand gets closer to the object so she doesn’t knock it over. We compared these variables before and after training,” Tudella explained.

Generally speaking, the researcher said, the training was able to increase the frequency of the reaching behavior and the number of bimanual reaches. The training also increased the number of times that the infant raised her hand to an object in the vertical position, which is considered the most mature and effective way of reaching because it facilitates actually grabbing the object. “In addition, the infants got faster and used more directed and precise movements, and there was less need for correction,” Tudella explained. Future studies are expected to be conducted to verify learning retention.

According to Cunha, one of the research objectives was to show how, with only one session of training, results can be achieved. “It is an age of incredible plasticity in an infant’s central nervous system, in which learning occurs very quickly. This simple method can be performed at home, without any expense.”

According to Tudella, the idea is to alert and train health professionals and educators so that they can readily detect delays in the development of reaching behavior and thus instruct family members on how to conduct the training. “We’re communicating this information through articles, seminars, speeches, courses and book chapters,” she said.

Partial findings have already been published in three articles in the journal Motor Control and one article in the journal Research in Developmental Disabilities. The group is currently studying the effect that the training has on institutionalized infants.

“We plan to conduct additional studies on infants with Down’s syndrome, cerebral palsy and myelomeningocele,” Tudella said.

The article Effect of training at different body positions on proximal and distal reaching adjustments at the onset of goal-directed reaching: a controlled clinical trial may be read at journals.humankinetics.com/mc-back-issues/mc-volume-17-issue-2-april/effect-of-training-at-different-body-positions-on-proximal-and-distal-reaching-adjustments-at-the-onset-of-goal-directed-reaching-a-controlled-clinical-trial.

The article The effect of a short bout of practice on reaching behavior in late preterm infants at the onset of reaching: A randomized controlled trial (doi: 10.1016/j.ridd.2013.09.028) may be read at www.sciencedirect.com/science/article/pii/S0891422213004228.

The article Reaching Behavior in Preterm Infants During the First Year of Life: A Systematic Review may be read at journals.humankinetics.com/mc-back-issues/mc-volume-17-issue-4-october/reaching-behavior-in-preterm-infants-during-the-first-year-of-life-a-systematic-review.

* With Fernando Cunha