Keywords: Appropriate for gestational age, Brazelton neurobehavioral assessment scale, Small for gestational age.

Identifying cerebral impairment as early as possible is one of the main goals of the neonatologist. The early detection of an abnormality should help us in our efforts to provide the infant with appropriate therapy. Most of the classical neurological tests are designed to identify motor impairment and are not as good at describing behavioral development. Similarly, radio imaging have been found to be inadequate in determining the prognosis in such babies(1). Neonatal behavioral assessment scale (NBAS) developed by Brazelton with its emphasis on assessing both the cortical and subcortical functions is an excellent mode of neonatal evaluation(2). It has high degree of sensitivity and specificity in determining the future outcome of newborn babies(3). The present study was conducted with the aim of assessing and comparing the neurobehavior of appropriate for gestational age with small for gestational age babies and observe pattern of improvement in neurobehavior during first 2 weeks of life.

The present study was conducted in the neonatal unit of our hospital during a two-year period from October 1999 to November 2001. The study included term appropriate and small for gestational age babies, with an Apgar score of >7 at one minute. Babies with congenital anomalies, illness during study period and on drugs were not included in the study.

The neonatal neurobehavioral assessment was performed in accordance with the procedure described by Brazelton(4). The examination consists of 27 behavioral items and 20 elicited responses. The behavioral items include response to various stimuli, motor activity, change in skin colour etc scored on a nine point scale. The scales are set so that the midpoint is the norm. The elicited responses like grasp, rooting, sucking, moro reflex etc. are scored on a three point scale. The infant score is based on his best and not on average. The neurobehavioral items from the scale are reduced to seven clusters viz., habituation, orientation, motor organization, range of state, autonomic stability, regulation of state and reflex derived conceptionally based on neurophysiology.

The assessment was standardized by the investigators by administering the test on 30 babies to achieve an inter-score agreement level of 90% for each baby done on three separate occasions. The behavioral assess-ment of the babies was done on 3rd, 7th and 14th day after birth. All the babies were exclusively breastfed. Scoring of each item was done for individual neonate in each group and then distribution of the scores of each item was tabulated for each group. Seven cluster scores for each neonate was obtained by taking mean of individual items of the each cluster. Cluster score for each group was obtained by taking mean of the scores for each neonate in the group(5). Unpaired t test has been used to compare the cluster scores between the different groups. The most probable cluster score, which differentiated between the groups, was analyzed using chi square test.

Seventy-eight infants were included for the study, of which 48 belonged to appropriate for gestational age (AGA) group and 30 to small for gestational age (SGA). The mean birth weight, length and head circumference of AGA infants were more than SGA infants. Gestational age, Apgar score and parity of mother were similar in both groups. Initial Prechtl’s state was low in all infants but as the test progressed the state improved in both AGA and SGA infants. (Table I). Mean values of all clusters for AGA and SGA babies on 3rd and 14th day are depicted in Table ll. Statistically significant difference was observed for all clusters between the AGA and SGA babies on most of the cluster items on 3rd and on 14th day.

Habituation 

5.65 (0.66)

4.98 (0.33)

<0.001

6.85 (0.50)

6.31 (0.58)

<0.001

Orientation

4.28 (0.33)

5.79 (0.53)

<0.001

5.92(0.57)

6.69 (0.66)

<0.001

Motor organization

3.46 (0.56)

3.54 (0.70)

NS

5.53 (0.84)

5.26 (0.76)

<0.001

Range of state

5.89 (0.62)

4.59 (0.68)

<0.001

6.31 (0.55)

5.91 (0.55)

<0.001

Autonomic stability

6.5  (1.1)

4.82 (0.93)

<0.001

7.16 (1.0)

7.5  (0.46)

<0.001 

Regulation of state

5.91 (1.0)

4.72 (0.77)

<0.001

4.16 (1.0)

6.3  (0.98)

<0.001

Reflex

1.87 (0.28)

2.12 (0.22)

NS

0.87 (0.33)

0.97  (0.21)

NS

The mean score for habituation cluster shows that the AGA group of infants were performing in the optimal range. Their behavior is characterized by shut down of body movements, diminution in blinks and respiratory changes after 6-8 stimuli. The performance of the babies significantly improved on the 7th and 14th day. This capacity to habituate against the visual, auditory and painful stimulus helps the babies to adapt adequately to the stimulation rich environment while awake, feeding and during deep sleep. The performance of SGA infants on habituation cluster was lower than the AGA infants. The shut down of body movements, diminution in blinks and respiratory changes occurred after 9-10 stimulus. The performance improved and by day 14, SGA babies were performing as good as the AGA babies. Compared to the AGA infants they were less adept in habituating and shutting out distorting stimuli. Habituation to pinprick was especially low and continued to stay low on subsequent examinations.

The mean score for orientation cluster in AGA infants falls at low to mid-range level of the scale. On bringing visual and auditory stimulus in the vicinity of the babies they focused briefly on objects and followed them to only 30-degree arc. The participation of head for visual tracking improved as the days progressed and on day 14 the babies could track the objects up to 60-degree arc. This low score on the 3rd day may be due to the difficulty in bringing the babies to the alert state to perform optimally and low social responsivity of mother and infant during the initial few days. In orientation cluster, SGA infants have performed much better. The orientation response continues to stay higher on day 14. These infants alerted quickly to inanimate and animate visual and auditory stimulus with sustained fixing and smooth following to a 30-60 degree arc. The auditory stimulus such as human voice, bell and rattle were more attractive than the inanimate visual stimulus.

The mean score for motor cluster as assessed by alertness, general motor tone, smoothness of movement of limbs and pull to sit falls on a lower range on day 3 but shows a significant improvement on day 14. Most of the important motor activities were seen in Prechtl’s state 5 and 6. Alertness, good tone, predominantly smooth movements and a sustained effort to control head characterize the motor behavior. Rapid change of state from 1-5 or 6 showed an immature and ill sustained motor behavior while slow and steady change of state resulted in a mature and sustained behavior. The performance of SGA infants in motor cluster is as good as the AGA infants.

In range of state cluster, AGA infants were performing in optimal range with no significant change as the days progressed. The behavior is characterized by low irritability, peak of excitement, and rapidity of build up. The response to defensive movements and consolability is high with good activity, less tremulousness and startle during examination. SGA babies initially tended to be more irritable and showed rapid build up from one state to another. The responses however progressively improved and by day 14 the performance of SGA infants was comparable to the AGA babies.

The autonomic regulation was the best behavior response shown by the AGA infants in the present study. In general the infants showed low frequency of state swing during examination with good healthy skin. On 3rd day babies were tremulous with exaggerated startle response, skin color though healthy changed while uncovering or on crying. On 14th day tremulous and startle response decreased, skin color was healthy with minimal changes. Adaptations to temperature changes were low with rapid changes in skin color and delayed recovery to healthy skin color among SGA babies. These infants scored significantly higher than AGA infants in autonomic stability and regulation of state by 14th day.

In reflex the scores of SGA babies on all days were similar to AGA infants and there was no statistically significant difference between them. Good improvement in most of the behavioral assessment areas could be because of special instructions routinely given to the mothers in our hospital to take care of the SGA babies. Mothers in the present study were given specific instructions for frequent feeding, proper techniques of maintaining temperature and clean and gentle handling.

Similar behavior response was obtained in AGA babies from other studies conducted in India with some variation in few clusters. Iyer et al showed similar responses in clusters of habituation, motor organization, regulation of state, autonomic regulation and reflex(6). In orientation, the response did not show much improvement during first month while the present study showed an initial improvement followed by stabilization of score. In range of state they observed that the response was at a lower range while the present study showed an optimal response. Mallik, et al. in their study showed a higher response in orientation with significant improvement over one month and a lower response in reflex cluster on day 3(7). Khadilkar, et al. got a lower response in autonomic stability and the rest of the responses similar to the present study(8). Abrol observed higher response in range of state cluster similar to the present study(9). The minor variation observed in various studies could be due to the differences in sociocultural environment.

Assessment done on Caucasian neonates by Als, et al. revealed that the babies are inactive and oriented poorly to the stimulus(10). They found it difficult to improve the Prechtl’s state of the babies to obtain optimal response to behavioral assessment. In contrast in the present study SGA infants showed a much more stable state change and a mature behavior. Smaller head with proportionately smaller limbs can explain the smooth movement of head towards the auditory and visual stimuli and thus better response to all the stimuli in orientation clusters. The study done by Iyer, et al. had similar behavior to the present group(11). Brazelton’s study on Zincanteco Indian neo-nates in South America had some similarities to the present one(12). Svenningsen, et al. in their study of SGA infants from Sweden showed a similar high response in orientation(13). They noted better defensive movements, poor regulation of state and poor autonomic stability than the present study.

Our study on SGA infants was done in a controlled environment with common instruction for newborn care. The high score of SGA babies on subsequent examination underlines the importance of special care. It will be interesting to analyze the behavior of SGA babies in the community practicing routine newborn care. This study model will generate quantitative baseline data from which ethnographic exploration of behavior of babies using NBAS from South India can be made. However, considering the complex nature of the Brazelton’s NBAS, which is time consuming and requires training before administration, a modified scoring can be attempted.

Contributors: RNRP and VB conducted the study, RNRP analyzed the data. RNRP drafted the manuscript which was edited by VB. VB will act as the guarantor of the manuscript.

Funding: None.

Competing interests: None.

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