Tactile Stimulation and Behavioral Development among Low-Birthweight Infants N o r m a n S o l k o f f , PhD, and Diane Matuszak, MD S t a t e University o f N e w Y o r k at B u f f a l o

A B S T R A C T : The N e o n a t a l Behavioral A s s e s s m e n t Scale was a d m i n i s t e r e d t o a g r o u p o f p r e m a t u r e i n f a n t s b o t h p r i o r t o and following a nursery p r o g r a m o f enriched tactile stimulation. The same i n s t r u m e n t was a d m i n i s t e r e d t w i c e t o a control g r o u p o f p r e m a t u r e s w h o received n o intervening " e x t r a " s t i m u l a t i o n . Whereas c o n t r o l infants s h o w e d changes o f 2 or m o r e p o i n t s o n o n l y 2 o f t h e instrum e n t ' s 26 scales, t h e e x p e r i m e n t a l babies s h o w e d positive changes o f 2 or m o r e p o i n t s o n 11 scales. There were no d i f f e r e n c e s in w e i g h t gain b e t w e e n t h e t w o groups.

Based upon the supposition that some of the debilitating sequelae of low birthweight or prematurity may be related to a dearth of stimulation during the neonatal period, several investigators have attempted to study the effects of sensory enrichment procedures, introduced soon after birth, on a variety of developmental indices. Most of this research has been cross-sectional and has typically involved the application of tactile, kinesthetic, visual, or auditory stimulation, either independently or in some combination. The results of such enrichment programs introduced while prematures were still in their nurseries have been generally positive. With the administration of " e x t r a " tactile stimulation, prematures gained weight more rapidly, were more active [1], cried less, and passed less feces [2] than did low-handled or control babies. Similar results were observed with weight as the dependent variable when infants received increased kinesthetic stimulation in the form of rocking [ 3]. In a stimulation program that combined tactile, kinesthetic, and visual stimulation, Scarr-Salapatek and Williams [4] found greater alertness, better grasp reflexes, and increased weight gain at the end of from 4 Dr. S o l k o f f is at the S t a t e University o f N e w York at Buffalo, D e p a r t m e n t o f P s y c h i a t r y , Buffalo, N e w York 14214.

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t o 6 w e e k s a n d higher Cattel scores at the end o f 1 y e a r . Finally, w i t h a u d i t o r y s t i m u l a t i o n ( m o t h e r ' s voice) as t h e i n d e p e n d e n t variable, p r e m a t u r e s s h o w e d greater m a t u r a t i o n a l d e v e l o p m e n t a n d b e t t e r visual and a u d i t o r y f u n c t i o n [ 5 ] . T h e p r e s e n t research was designed b o t h t o e x p l o r e t h e r e l a t i o n s h i p b e t w e e n tactile s t i m u l a t i o n a n d t h e p e r f o r m a n c e o f p r e m a t u r e n e o nates o n the N e o n a t a l Behavioral A s s e s s m e n t Scale [6] a n d t o verify the e f f e c t s o f tactile s t i m u l a t i o n o n w e i g h t gain o f l o w - b i r t h w e i g h t infants. Method

Subjects Eleven low-birthweight infants, eight girls and three boys all located in the Intensive Care Nursery of the Buffalo Children's Hospital, comprised the study sample. The mean birthweight for the group was 1,470 gm, with a range of from 978 to 1,871 gm, and their mean gestational age was 31.1 weeks, with a range of from 28 to 37 weeks. No infant with respiratory distress, convulsions, symptomatic hypoglycemia, recurrent apnea, or serum bilirubin levels above 13 mg per 100 ml were included in the study.

Instruments The Neonatal Behavioral Assessment Scale [6] was designed to investigate the temperamental, reflex, and early "social" behavior of neonates. The following behavioral characteristics are assessed by this instrument: states of arousal during the examination, speed and frequency of state changes, tonus, responsiveness at peak periods of excitement, visual and auditory orientation and following, reactions to tactile stimulation and temperature changes, defensive movements, habituation to light, sound, and pin prick, hand-to-mouth facility, tremulousness, startle, activity, and social interest in the examiner. Based upon ratings on a 9point scale, 4-week test-retest reliability coefficients for full-term neonates ranged from .62 for a 1-point disagreement to an average of .82 for 2-point disagreements. The mean item reliability based upon a 5-point scale ranged from .59 for a 1-point disagreement to .78 for a 2-point disagreement. Intertester reliability was also quite high, averaging in the .90s [7]. Although no norms have been developed for low-birthweight infants, differences on several of the Cambridge scales between environmentally enriched and control premature neonates have been demonstrated [4].

Procedure The experimental group consisted of five girls and one boy (mean birthweight = 1,375.3 gm; mean gestational age ffi 31.2 weeks) who, in addition to their routine nursing care, received 71A minutes of extra handling, in the form of stroking,

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during each of 16 hours per day for 10 days, for a total of 1,200 minutes of tactile stimulation. A group of five control infants, three girls and two boys (mean birthweight = 1,564.6 gm; mean gestational age = 31 weeks), received routine nursery care in the same room as the experimental infants, and by the two nurses who were also responsible for providing the experimental stimulation program. Each experimental infant was tested twice on the neonatal scales: once immediately prior to the initiation of the stimulation program and again at the end of the 10-day stimulation period. The mean age of the infants when stimulation was introduced was 14.2 days, postbirth. The same test-retest procedure was employed with the control infants who did not receive the extra handling during the 10-day period. Testing was conducted by the co-author, a 4th-year medical student, whose extensive clinical and research experience with the instrument resulted in her being selected as the one person in Buffalo to conduct training programs in its use for medical students, nurses, and pediatricians. The examiner had no knowledge of the experimental or control status of any of the infants. Results Because o f the small Sample size, n o f o r m a l statistical p r o c e d u r e s w e r e a p p l i e d t o t h e data, a n d all findings, a l t h o u g h suggestive o f imp o r t a n t and i n t e r e s t i n g trends, m u s t t h e r e f o r e be c o n s i d e r e d t e n t a t i v e . A f t e r 10 d a y s a n d 1 , 2 0 0 m i n u t e s o f e x t r a tactile s t i m u l a t i o n , the e x p e r i m e n t a l i n f a n t s s h o w e d changes o f 2 or m o r e p o i n t s o n 11 o f 26 ( n u m b e r o f smiles o m i t t e d ) 9 - p o i n t n e o n a t a l r a t i n g scales. C o m p a r e d t o t h e i r p r e s t i m u l a t i o n p e r f o r m a n c e , t h e y n o w h a b i t u a t e d m o r e rapidly t o light and s o u n d , w e r e m o r e alert t h r o u g h o u t the d u r a t i o n o f t h e e x a m i n a t i o n , h a d i m p r o v e d general b o d y t o n u s , h a d b e t t e r h e a d c o n t r o l in r e s p o n s e t o a pull to sit, were m o r e c o n s o l a b l e , r e s p o n d e d with m o r e r a p i d a v o i d a n c e to n o x i o u s stimuli, c h a n g e d s t a t e s m o r e o f t e n , and, finally, d e m o n s t r a t e d greater h a n d - t o - m o u t h facility. Over a similar 1 0 - d a y p e r i o d , c o n t r o l infants, w h o did n o t receive e x t r a handling, c h a n g e d 2 or m o r e p o i n t s o n o n l y t w o scales: T h e y were less able t o q u i e t t h e m s e l v e s during an a r o u s e d state, a n d t h e i r defensive m o v e m e n t s in r e s p o n s e t o a d i a p e r p l a c e d o v e r t h e i r faces were m o r e efficient. Ratings o n all o t h e r scales w e r e p r a c t i c a l l y identical t o t h o s e received 10 d a y s earlier. T h e m e a n weight gain over t h e 1 0 - d a y p e r i o d was virtually t h e s a m e f o r b o t h groups. T h e m e a n gain f o r t h e e x p e r i m e n t a l i n f a n t s was 3 3 3 . 3 g m a n d f o r t h e c o n t r o l s , 3 1 2 . 2 gm. Discussion

O u r results w i t h t h e C a m b r i d g e Scales s u p p o r t t h e findings o f ScarrS a l a p a t e k a n d Williams [4] w h o d e m o n s t r a t e d t h e b e n e f i c i a l e f f e c t s

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of a general stimulation program (visual, tactile, kinesthetic) for a group of 15 black, low-social class, low-birthweight infants. Although the performance of their control infants was superior to that of the experimentals prior to the introduction of stimulation, at the end of 4 weeks, the stimulated infants showed "slight to significant advantages on nearly all the scales." However both our own previous findings [1] and those of Scarr-Salapatek and Williams [4] indicating greater in-nursery weight gain among stimulated infants were n o t confirmed in the present study. Of particular interest is the improved behavioral development observed on the Neonatal Behavioral Assessment Scale for infants under separate enrichment programs which differed both in sensory modalities stimulated as well as in the duration of the stimulation. Although our intervention program consisted of only tactile stimulation, delivered over a 10-day period, we observed similar improvements in behavioral and early social development to those reported by ScarrSalapatek and Williams [4] who produced a far more complex stimulus environment for their very low social class infants and for over a much longer period of time. It would appear then that for biologically disadvantaged infants, even minimal enrichment conditions could result in more optimal development, at least during and immediately following stimulation. However, an important issue, which has not yet been systematically studied, concerns the durability of the advantages observed among stimulated prematures compared with routinely cared-for controls. For example, will the developmental gains produced by an enriched nursery environment persist following discharge, and if so, for h o w long? In our first study using tactile stimulation, we found that although the weight gain differences between experimentals and controls disappeared soon after the stimulation program was terminated, the experimental infants, at the end of 7 months, were found to have higher developmental scores and to be living in a more stimulating home environment. At that time we speculated that if stimulation produced improved behavioral development, the mothers of these infants might also be more responsive, thereby maintaining a more diverse and enriched stimulus environment at home. This hypothesis awaits further confirmation. A far more frequent finding points to the decay of poststimulation improvements over time. In such instances procedures will perhaps need to be developed that will allow for the periodic reinstatement of a similar enrichment program throughout the first several years of life. Positive effects on a variety of behavioral assessment scales were found as a function of tactile stimulation introduced for premature

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infants during their stay in the nursery. However, no differences in weight gain were found between stimulated and routinely cared-for infants. It n o w must be determined whether the observed positive developmental changes are durable or if stimulation reinstatement procedures are necessary so that the advantages related to an enriched nursery environment may be retained. References 1. Solkoff N, Weintraub D, Yaffe S, et al: Effects of handling on the subsequent development of premature infants. Dev Psychol 1:765-769, 1969. 2. Hasselmeyer EG: The premature neonates' response to handling. A m e r Nurses' Assoc 11:15-24, 1964. 3. Friedman DG, Boverman H, Griedman N: Effects of kinesthetic stimulation on weight-gain and on smiling in premature infants. Paper read at the annual meeting of the American Orthopsychiatric Association, San Francisco, April 15, 1969. 4. Scarr-Salapatek S, Williams ML: A stimulation program for low birthweight infants. A m e r J P u b Health 62:662-667, 1972. 5. Katz V: Relationship between auditory stimulation and the developmental behavior of the premature infant. Nursing Res Conf 7:103-117,1971. 6. Brazelton TB: Neonatal Behavioral Assessment Scale. Spastics International Medical Publications, Monogr 50. London, William Heinemann, 1973. 7. Horowitz FD, Self P, Paden L: Newborn and four-week retest on a normative population using the Brazelton Newborn Assessment Procedure. Paper presented at the meeting of the Society for Research in Child Development, Minneapolis, April 1971.

Tactile stimulation and behavioral development among low-birthweight infants.

The Neonatal Behavioral Assessment Scale was administered to a group of premature infants both prior to and following a nursery program of enriched ta...
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