No abstract

Habituation is a basic form of learning and probably requires an intact central nervous system. Habituation in the behavioural response t o vibration in 40 normal human fetuses was compared with that in a group of high-risk pregnancies with an increased risk of fetal neurological damage. Highly significant differences in habituation patterns between the high-risk groups and normal control subjects were found. This test may offer a method of assessing the integrity of the fetal central nervous system.

This study measured the antenatal fetal heart rate changes in response to a single vibrotactile stimulus. In a group of 11 normal patients, this resulted in a significant change in the fetal heart rate (P less than 0.001). Sixty-eight high risk patients were also tested. In the group of 25 patients whose fetuses showed no response to the stimulus, there were 4 stillbirths and 4 neonatal deaths; 23 of these 25 infants were small for gestational age (SGA) compared to only 15 of the 43 that showed a response to the stimulus. Fetal habituation to a repeated vibrotactile stimulus was measured in a control group of 40 patients who had a normal antepartum and intrapartum course and delivered infants in an optimal condition. The same was done in a study group of 48 patients who delivered infants that were SGA. These infants were assessed at 1 year of age by the Griffiths Mental Developmental Scale (GMDS). Infants that were SGA did not differ significantly from the control group. However, infants who had a normal antenatal habituation pattern had a significantly better performance (P less than 0.01) compared to infants who had an abnormal antenatal habituation pattern.