Auditory Processing

Auditory Processing

Students with ASD commonly have auditory processing differences than others. Those that I see in either a school or early intervention setting can’t isolate one auditory input within a field of others. They also react more adversely to typical auditory noises such as people talking. In the younger children, it seems they cannot get used to a sound. A preschool student covers his ears in the OT room a month after we had a fire drill while in that setting. In the middle school, it seems that the older students have learned to block all stimuli out. Not all of the students I see exhibit self stimulatory behaviors, however, many do. They may do these to focus their attention to that in avoidance of other stimuli or some will do it to create stimuli.
From reading several articles overall, it seems that there are neurological differences in children with ASD from their typical peers. The true is also found with adults. A report by Boddaert, N., Chabane, N., Belin, P. et al. (2004) also indicates that there are differences in areas of activation between children and adults with autism from PET scans. They performed a study with 10 boys and girl ages 4 to 10 years who have a diagnosis of autism. The PET scans were done during induced sleep with inactive listening to speech-like sounds. The typical auditory areas of the brain are less activated while other areas of the brain are. In typical children, the area includes the superior temporal cortex bilaterally mainly the left side and this is not activated in children with ASD (p. 2119). In children with ASD areas outside the auditory cortex were used. These included” the left temporal pole, the bilateral cingulum, the bilateral posterior parietal and the cerebral hemispheres, and the brainstem” (p. 2119). Several of these compose Brodmann’s area. The study also found that “in autistic children the abnormal right frontotemporal activation” (p. 2119) was not observed as it was in adults with ASD when compared to a similar study with adults. The authors also discuss that their abnormal cortical “auditory processing…can be involved in inadequate behavioral responses to sounds and in language impairments characteristic of autism” (p. 2117). They also indicate, however, that those with ASD can be misdiagnosed a deaf.
Another 2 studies by Dunn, Gomes, and Gravel (2008) indicates that children with autism can either be hyper or hyposensitive to sound as discussed by other authors (p. 52). This study aimed to study event related potentials (ERPs) and mismatch negativity (MMN) in automatic and attentional processing during unpredictable changes in auditory input. The automatic processing mentioned is attentional in nature and can process typical auditory stimuli. “MMN has been elicited from adults by changes in a variety of acoutistic features, such as intensity, frequency, duration, and perceived location, and by changes in auditory patterns “(Naatanen, 1992; Naatanen, Jacobsen and Winkler, 2005, and Picton et al., 2000 in Dunn et al., 2008 p. 53). The authors also cite studies where latency is longer in children with ASD than in adults with ASD in regards to MMN. (p. 54). Other studies were discussed. The first study measures MMN in 68 children half who were diagnosed with ASD. They were matched by age, non-verbal IQ, and handedness. An oddball paradigm was used. In the second study the method was the same however, it was done for both ignore and attend situations. All children underwent a battery of standardized assessments in order to match samples. The procedure, an oddball paradigm, used a deviant stimulus randomly in a series of normal tones. In study one results were comparable to previous literatures noting that the “MMN was the largest in the frontal-central region and very small at the sides of the head and inverted in polarity at the mastoids for typically developing children “(Dunn et al., 2008, p. 58). “In the children with autism, there was a small difference between the standard and deviant waveforms in the fronto-central region that continued across the sides of the head and did not invert polarity at the mastoids” (Dunn et al., 2008, p. 58). The results were further analyzed and it was discovered the amplitude of MMN may increase with age. (p. 60). Abnormal automatic auditory processing may occur in those with ASD. The authors pursued study two in order to investigate the findings and that those with ASD had smaller MMNs than typical peers. A study by Gommes et al. (2000) was discussed. It found that “attention enhanced the amplitude of the MMN” (in Dunn et al, 2008). Study two used 20 children; half with ASD who were screened the same as in Study One. Results “ did not differ on the Pattern Analysis, memory for Digits or Memory for objects subtests of the Stanford-Binet” ( Dunn et al., 2008, p. 62). The study revealed no significant differences in reaction time or accuracy between the two groups. These two studies had similarities and contrasts with previously published studies. Receptive language and age did not influence the results. Auditory discrimination requires attention for unpredictable changes where it does not for those without ASD. “Data indicating that children with autism demonstrate significantly attenuated or absent MMN until the age of 9 is of significant interest, as typically developing children demonstrate this automatic component in response to simple tone contrast by the age of 4” (Kurtzberg et al., 1995; Shafer, Morr, Kreuzer and Kurtzberg, 2000 in Dunn et al., 2008, p. 68). This indicates that more effort is required in auditory processing while younger and that it requires attention/doesn’t occur automatically long past the change in typical peers. This may be why my clinical observations of my student’s behavioral reactions or stimming behaviors seem to occur more often with younger students. I still question changes in adolescence as well but did not find studies on that specific age group. The authors so mention that auditory processing requiring or stealing attention may lead to memorization of independent facts separate from the whole or linking concepts together, organizational issues, as well as socialization, education and language complexities.
There is one final article I wanted to include in this posting. Bigler, Mortensen, Neeley et al. relate the superior temporal gyrus to auditory processing, language and also social cognition. The authors do conduct a study of the role of the STG in psychometric IQ and language function. The results will not be discussed in detail within this blog. It is worth investigating. It does not go into auditory processing but is important to note the differences in language and socialization in children with ASD.
In light of the above research findings, there are numerous treatment strategies that could assist students with ASD who exhibit auditory processing difficulties. Since they cannot sustain attention and also demonstrate socialization issues, I think that preparing them in advance for situations with a pictorial routine, PECS systems for transitions, a daily schedule and social stories may be as critical as sensory and coping strategies. There are various programs that target auditory processing such as FastForward or therapeutic Listening however research I have reviewed so far does not include those with ASD and also does not strongly indicate the results were from the program itself.
Bigler, E., Mortensen, S., and Neeley et al., 2007). Superior Temporal Gyrus, Language Function, and Autism. Developmental Neurology, 3 (2), p. 217-238.
Boddaert, N., Chabane, N., Belin, P. et al. (November 2005). Perception of complex Sounds in Autism: Abnormal Auditory Cortical Processing in Children. American Journal of Psychiatry, 161: 1, p. 2117-2120.
Dunn, M., Gomes, H., and Gravel, J. (2008). Mismatch Negativity in Children with Autism and Typical Development. Journal of Autism and Developmental Disorders, 38: p.52-71.