Bruxism and Other Stress Symptoms in Children or Young Adults with Autism or Other PDDS, With or Without Down Syndrome

Renato Cocchi M.D., Ph.D. (Sociology) Presented at the 3rd World Congress on Stress, Dublin 24-27 September 2000

Reprinted with the permission of Renato Cocchi Via A. Rabbeno, 3 42100 Reggio Emilia, Italy +39 0522 320 716 Mobile +39 348 5145 520 URL: http://www.stress-cocchi.net

Summary

Two groups of autistic or other Pervasive Developmental Disordered (PDD) Ss (Group 1: 13 F + 20 M, all with Down's syndrome; Average age at 1st consultation 89.91 ± 40.14 months; Group 2: 18 F + 39 M; Average age at 1st consultation: 108.25 ± 59.60 months) were evaluated for the bruxism's prevalence, or the co-presence of bruxism, upper respiratory tract infections, easiness, and spastic constipation and/or diarrhoea as reactions to an internal stress or stresses.
As suggested, i. Down Ss who own two factors of internal stress (the chromosomal anomaly and autism or other PDD) presented more bruxism than non-Downs (.033); ii. Down Ss showed a larger co-presence of these three symptoms than non-Downs (.02).
Stress can also arise from internal factors, as it happens for genetic and chromosomal anomalies. The amount of internal stress could be a variable leading to multiple stress reactions.

The link between stress and bruxism has a quite long and controversial history. The psychological stress was asserted as the main causal factor, according to experimental data, but it cannot fully explain the night bruxism. (Morse, 1982).

This investigation aims to evaluate if there are any difference of bruxism's prevalence (or bruxism and other stress symptoms) as a function of internal stress linked to the illness. On other terms I expected to found more bruxism in Down Ss, with autism or PDD than in autistic or PDD Ss without Down syndrome or other illnesses.

Materials and method

We checked out clinical records of all autistic or PDD children or young adults' one of us had in consultation since 1980. From these records we collected: sex, age at 1st consultation, chromosomal or genetic diagnosis, type of autism or PDD according to DSM-IV, presence and type of bruxism.

Results

All autistic or other PDD Down Ss fitted the above-mentioned criteria and formed Group 1 (33 Ss).

Among autistic or other PDD non-Down Ss three were suffering from Tuberous Sclerosis and two others from Rett's syndrome. Since these five had a second illness, they did not fit our inclusion criteria, being more similar to autistic or other PDD Down syndrome Ss. For that reason they did not have inclusion into the Group 2 (57 Ss).

Table 1: Epidemiological data.

As we can see there are moderate differences as for M/F ratio and age at 1st consultation, but we think that it does not invalidate our investigation. Several Group 2 Ss came at 1st consultation as young adults because parents hoped to find some help for current troubles, namely sleep troubles and self-injuring.

Table 2: Chromosomal diagnosis of 21 trisomy Ss Group 1 (Down's syndrome Ss): Chromosomal diagnoses

The lack of Down Ss with translation is probably due to the reduced extent of the sample. Remaining chromosomal diagnoses fitted the international ranges.

Table 3: Diagnoses according to DSM-IV (autism or other PDD).

Our two samples did not differ as for DSM-IV diagnoses.

Research 1: results on bruxism's prevalence.

Table 4: Prevalence of bruxism.

Chi Square = 12.252 with 5 df and p = .033

Research 2: Results on bruxism and other stress symptoms prevalence

Table 5. Co-presence of the three symptoms in Down and non-Down Ss. Key:
1 = present and 0 = not present; 1^st digit = URTI easiness; 2^nd digit = spastic constipoation etc.; 3^rd digit = bruxism

Chi Square = 22.846 with 7 df and p .002

The distribution of the three-symptoms coding is significantly different in our two groups, with a larger presence of two or three symptoms in the Down group.

Graphic 1: Trend of the three-symptoms co-presence within the two groups.

Discussion

It is not the first time that one of us uses comparison between autistic or other PDD Down or non-Down subjects (Cocchi, 1988; Cocchi and Bonaduce 1988a, 1988b; Cocchi 1990, 1991a, 1991b, 1991c; 1991d).

As for the epidemiology, autistic of other PDD Down Ss presented an increased prevalence of prematurity, low birthweight and squint.

Autistic or other PDD non-Down Ss showed increased EEG anomalies. Autistic or PDD non-Down Ss had increased sudden anxiety, sameness, hypersensitivity, rituals and aggression (Cocchi, 1988).

Same non-Down Ss had lesser easiness to upper respiratory tract infections, as compared to similar Down Ss (Cocchi and Bonaduce, 1988a).

The self-injuring behaviour prevails in autistic or other PDD non-Down Ss when compared with similar Down Ss, but the observed difference did not reach a significant level. (Cocchi and Bonaduce 1988b).

In the current investigation we do not think that different M/F ratio and different average age at 1st consultation could negatively influence the results.

As for research 1, according to our hypothesis, autism and other PDD non-Down Ss presented lesser bruxism than similar Down Ss. In this way we found confirmation that the amount of stress is a variable to count on, when the internal stress factor is genetic as it happens in Downs.

Since the bruxism without any occlusional cause is a stress reaction, we can understand its prevalence by evaluating the extent of stress factors, in a virtual manner.

As for research 2, symptoms like URTI easiness, and spastic constipation and/or diarrhoeas were selected as stress symptoms according to our previous research (Cocchi, 1998; Cocchi 1996; Cocchi 1997a, 1997b). On URTI easiness as a symptom of stress there exists concordant literature recently elsewhere reported by one of us. (Cocchi 1999 )

Spastic constipation with little balls' faeces and/or diarrhoeas were considered a symptom of excess vagal stimulation of the bowel following stress. We found evidence that stress can elicit not only vagal symptoms like that, but can also increase peripheral acetylcholine. (Hata et al., 1986; Kita et al., 1986).

As we said, non-Down Ss presented lesser co-presence of URTI easiness, spastic constipation and/or diarrhoeas and bruxism than Down Ss. So we can confirm that the stress amount is a variable to consider, when an internal stress factor is genetic as it happens in Down's syndrome.

Why these symptoms have different prevalence, with a significant difference as for URTI easiness, and non significant for spastic constipation and/or diarrhoeas, and bruxism (at least how here summarized)? That is something too hard to explain at the moment.

Conclusion

Our research aimed to find some different prevalence of bruxism (or bruxisms and other stress symptoms) according to the amount of internal stress produced by one or more illnesses.

We expected more bruxism (or more bruxism and other stress symptoms) in autistic or other PDD Down Ss than in similar non-Down ones.

Referring to our two groups of probands, we exactly found it. Of course, this fact does not give any information about the individual resistance to stress, which surely needs a different type of investigation.

References

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