It has recently been reported that the first signs of autism occur during infancy and that between 6-12 months of age infants with ASD may start to produce more repetitive movements such as hand flapping.
Early signs of altered sensory processing are among the first signs that distinguish infants who are later diagnosed with autism spectrum disorder (ASD). As the infants develop and grow the differences in sensory responsivity between those infants with ASD and typically developing infants increase and become more obvious. By the time the infant grows and attends preschool sings of hypo-responsiveness are reported such as ignoring loud sounds and not responding to pain. Since infants with ASD generally present with an altered sensory system, they may also be hyperresponsive to certain stimuli such as sound or touch. (M. Hadders-Algra, 2022)
Evidence of this alteration in the sensory system can be observed in early infancy during both the non-nutritive and nutritive suck. Infants with hypo-responsiveness may present with habituation to the nipple. Habituation refers to the “diminishing of a physiological response to a frequently repeated stimulus; a drop in arousal.” When the nipple is first placed in the infant’s mouth it gives the infant a novel stimulus that then triggers active sucking. The NNS is typically an alteration of bursts and pauses with bursts of not more than 5-20 sucks lasting not more than 7 seconds (A. Sameroff, 1973). We, therefore, anticipate that after the first pause the infant will re-initiate the second burst. Some infants do not re-initiate until a new stimulus is presented, i.e., resistance, turning, tipping the pacifier. Caregivers kindly report that these infants “forget the pacifier is in the mouth so you have to remind them” This only occurs because the infant has an altered sensory system and has habituated to the stimulus of the pacifier.
When the infant is hyperresponsive he/she demonstrates perseveration on the pacifier. Perseveration refers to “behaving in the same way over and over again; getting stuck.” Sucking activity is initiated when the pacifier is presented but the typical burst/pause pattern is not noted. Instead, the infant continues to suck non-nutritively at the rate of 2/sucks/second without stopping to take a pause. In this case caregivers kindly report “he is very hungry and trying to get milk out of the pacifier.” Perseveration is an indication of an altered sensory system and is not a normal response.
When the intra-oral sensory perception of the infant is severely impacted the infant may not be able to differentiate between the NNS and NS and may fail to demonstrate a rate change from 2/second on the pacifier to 1/second when the bottle is introduced. This infant may actually be transferring liquid but has no intra-oral sensory awareness of this. Infants such as these are at risk of aspiration and attempts at oral feeding should proceed with caution.
Another sign of an altered sensory system in the infant is poor adaptability. These infants are not able to make a smooth transition easily and, therefore, are unable to adjust to changes in nipples, formulas, caregivers, or position. Upon evaluation of the sucking pattern based on the NOMASâ infants may demonstrate a normal suck pattern on one nipple but a disorganized suck pattern when the nipple is changed i.e., from a straight nipple to an orthodontic nipple. (MM Palmer, 2015)
I would like to hypothesize that an infant with an altered sensory system can be identified from the first time oral feeding is introduced by habituation (hypo-responsiveness), perseveration (hyperresponsiveness) and by the inability to adapt to environmental changes and to make smooth transitions.
Follow-up for these infants will be of the utmost importance in order to determine whether or not they are diagnosed with autistic spectrum disorder later.
References:
Hadders-Algra M. “Emerging signs of autism spectrum disorder in infants: Putative neural substrate”, Developmental Medicine and Child Neurology, November 2022, Vol. 64, Issue 11, p. 1344-1350.
Sameroff, A. “Reflexive and operant aspects of sucking behavior in early infancy”, Fourth Symposium on Oral Sensation and Perception: Development in the Fetus and Infant, DHEW Publication No. (NIH) 75-546, 1973, p. 135-151.
Palmer, M.M. “Developmental Continuum of Neonatal Sucking Performance Based on the NOMASâ (Neonatal Oral-Motor Assessment Scale)” Developmental Observer, 2015, Vol. 8, No. 1, p. 11-15.
Marjorie Meyer Palmer MA, NLP, CCC-SLP, Neonatal / Pediatric Feeding Specialist, Speech-Language Pathologist, Founder / Director NOMAS® International
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