AN UPDATE ON PERVASIVE DEVELOPMENTAL DISORDERS

AN UPDATE ON PERVASIVE DEVELOPMENTAL DISORDERS

Dr. Sitalakshmi George D.P.M., M.D. (Psych)

Pervasive developmental disorders are neuropsychiatric disorders occuring in the developmental period of life, characterized by deviant and delayed social, communicative and cognitive skills. Since it starts early in life, all mile-stones of development are affected and there is often an associated mental retardation. Even though the behavioural patterns are unique and different from mental retardation, language and specific developmental disorders, these behavioural patterns change as the child grows, and the presence of MR and psychiatric symptoms if present, further complicate the development and behavioural patterns. Each child is unique and presents challenges throughout its life. It is important that parents, professionals from diverse disciplines, coordinate in the diagnosis, management and training of these children.

Classification

We have come a long way since Leo Kanner's Infantile Autism. The diagnostic criteria have been refined over the years. The ICD-10 and DSM-4 are good, but still we do come across children with PDD who do not fit into these criteria. So a further fine-tuning is necessary. In the present ICD 10 & DSM-IV diagnosis includes Autism, Rett's Disorder, Childhood Disintegrative Disorders, Asperger's Disorder and PDDNOS.

Asperger's disorder (ASP) is very much similar to high functioning autistics (HFA). Cognitively children with ASP have better Verbal and poorer performance skills than children with HFA on standardized IQ tests. L. Wingin 1997 (Ref to Tanguary 2000 proposed three sub types based on social interaction, communication, imagination and behaviour. One was an aloof type. Who actively avoided, a passive type who accepted social interaction but did not seek it, and an active type, who accepts social interaction but interacted in an odd and eccentric way. Another category called Multicomplex developmental disorder (MCDD), suggested by Klin has symptoms autism with anxiety, psychotic thinking and aggression. These could represent an early manifestation of major affective disorder or schizophrenia. (Tanguary 2000).

Prevalence Rates

Three epidemiological studies from France, Norway and Japan, using strict ICD-10 Research Diagnostic Criteria, came with the following results. This French group reported a prevalence rate for autism at 1 per 2000 and for autism and other PDD taken together 1 per 600. The Norwegian group reported 1 per 2000 for autism. The Japanies group reported a prevalence of roughly 1 per 500 for autism, with 50% of the children with IQ above 85, suggesting a HFA.A.

Conservative estimate for prevalence of autism would be 1 per 2000 persons, and 1 per 1000 for autism and Asperger's (Tanguary 2000).

Neurological Studies in Autism

1. Genetic Studies

a. Twin & Family studies.

Several studies on twins indicate increased concordance of infantile autism in Monozygotic than in dizygotic twins. Bailey in a British twin study included a broader spectrum of related cognitive and social abnormalities, they found 92% of MZ twins versus 10% of DZ twins to be concordant. The variations in behavioural and cognitive manifestations were within MZ twin pairs as between pairs. They conclude that is under a high degree of genetic control, but what is inherited is a broad spectrum of related cognitive and social abnormalities (reference to Tanguary,2000)

b. Family studies suggest that there is an increased loading for both autism and autism like disorders in the first-degree relatives pf persons with autism. Piven's (1997) family study found higher rates of social and communication deficits and stereotyped behaviours in the relative in families with autism compared with relatives of families with Down's syndrome. The parents of autistics subjects and higher rates of aloof, rigid, hypersensitive and anxious personality traits with speech and pragmatic defects and limited friendships.

c. Chromosomal studies

The pervasive developmental disorders have been studied extensively. There are at least three large scale genome-wide scans of autistic pedigree studies (State et al 2000) One study suggested a linkage at locus on chromosome 7, the other to studies failed to replicate to finding. Amir identified Methyl-Cp G. binding protein 2 (MECP2), agene involved in Rett's Syndrome which is X linked (state,2000)

2. Neuropharmacological Studies:-

Several studies points to the involvement of serotonin in many of the symptoms of autism. Hyperserotonemia in autism may be heterogeneous with one sub group of subjects having increased 5 HT up take and another group having decreased 5-HT2 binding. (Tanguary 2000)

3. Neuroimaging Studies :-

In a 10 year review by Hendren (2000) on Neuro-imaging, the conclusion was that autism is associated with large total brain and vertical volume, a smaller cerebellum and brain suggesting an early neurodevelopment abnormality. Changes in autism are more likely to be left-sided, were as changes in Asperger's are more often right sided.

4. Electroencephlography & Event-Related Potentials

EEG abnormalities are seen more in autistic persons than the normal population, the findings are varied and nonspecific. The event related potentials (ERP) are useful to study hearing activity in autism. (Tanguary 2000).

5. Neuropathological Studies-

Indicate a large head circumference. Two MRI studies by Piven 1995,1996 confirm the increased brain volume. The number of Pukiinje cells were reported less in four studies. (Tanguary).

Pharmacotherapy -PDD

There is as yet no medication that is effective in treating social and relationship problems in autism. Medication for associated behavioural problems and psychiatric condition may be used, as in a non autistic population Eg:- Stimulants, mood stabilizers, anxiolytics, antipsychotics or antidepressants. Controlling the symptoms helps the autistics co-operate in the educational programms (Volkman 1999).

1. Megavitamine treatment for autism, the results are variable, some studies report 30% of children have improved. Pyridoxin and magnesium were found to be in effective in ameliorating autistic behaviour.

2. Fenfluramine - Lowers blood serotonin, reduces hyperactivity but not symptoms of autism.

3. Naltrexone - Reduced hyperactivity and restlessness, but not effective in reducing self-injurious behaviour.

4. Clonidine - Not effective in reducing symptoms of autism, only hyperactivity and irritability are reduced, but drowsiness is a main side effect.

5. Antidepressants:- Clomipramine helps in reducing repetitive thoughts and behaviour, and social relatedness improved in some subject. There are very few studies on the effectiveness of SSRIs. They appear to decrease hyperactivity, restlessness, agitation and obsessive thoughts.

Fluoxetine reduces depressive symptoms, improves mood and reduces ritualistic behaviour. (Volkman, 1999)

6.Neuroleptics:- Resperidon is effective in hyperactivity impulsivity, obsessive preoccupation and aggressiveness and increases socialization. Olanzepine has also been found to be effective in improving hyper activity, repetitive behaviour, self injurious behaviour and social relatedness. (Tanguary 2000).

7. Mood Stabilizers - Lithium is effective when there is an additional diagnosis of a bipolar disorder or there is a strong family history of a bipolar (Volkman 1999)

8. Stimulants - Very few studies. Some studies report an adverse effect. Children with Asperger's disorder may respond positively (Volkman 1999).

Social and Behavioral Therapies :-

There is no one treatment that works with everyone. Intervention needs to a tailored according to the strengths and handicaps, to enable the child to develop better social and communicative skills, and reduce stereotypic and bizarre behaviour. There are 2 fundamentally different approaches in teaching autistic children. One is a massed, discrete trail learning, it is a teacher/ therapist centered learning or behavioural learning. It focuses on teaching discrete and objectively defined behaviours, skills and facts. Reward and aversive stimuli are also used and teaching is directed through oral language. (Lovass Approach). The other approach is social pragmatic teaching, a child centered therapy. It uses visual verbal and tactile clues, there is a shared emotional experience and relies on naturally occurring events and views the child as an active learner and social participant. The TEACH program prescribes treatment to start early and continue in one form or another in to adulthood.

Conclusion

The scenario in Kerala has to improve as far as Management of autism is concerned. The medical profession has to familiarize themselves with the diagnosis criteria. Medicines have no role in changing the symptoms of autism. Symptomatic treatment for aggression, obsessions, anxiety and mood swings are effective. Most of these children are enrolled in special schools for the retarded, which did not cater to the special needs of autistic children. There are very few individuals who use the behavioural and social approaches with some success. There is no organized or comprehensive programme which addresses the many issues faced by the affected children and their families. ICONS in Trivandrum, Raksha in Fort Kochi, and Vimukti in Kochi have been involved in training of children with PDD. Navajyothi Child Psychiatry Centre has recently taken up an Autism Project aimed at capacity building of Special Schools in Ernamkulam District, In the management of children with PDD.

Reference

Volkman F., Cook E.H Pomery J Realnuto G. and Tanguary P.E. (1990). Practical Parameters For the assessment and adults with autism and other pervasive developmental disorders. J. An. Acad Child Adolesc Psychiatry Supplement 38: 32 S-54 S.

Stat M.W., Lombroso P.J., Paul D.L., Leckman J.F. (2000). The genetics of childhood psychiatric disorders: A decade of progress. J. An. Acad Child Adolesc Psychiatry 39: 946-964.

Hendren R.L. Backer I.D., Pandina G.J., Review of Neuroimaging Studies of Child and Adolescent Psychiatric disorders from the past 10 years. J. An. Acad Child Adolesc Psychiatry 39: 815-828.

Tanguary P.E., (2000) Pervasive developmental disorder. A 10 year review J. An. Acad Child Adolesc Psychiatry 39: 1079-1095.