01 NRDC Dyslexia 1-88 update - Texthelp

70
Research Report
The self-organising systems model of reading disability contrasts with the essentially linear
theories reviewed in Part two by drawing on non-linear concepts of the process of
development.
The model challenges the assumption of specificity in dyslexia and in other learning
disabilities.
It captures the dynamic nature of development and it explains why ‘compensated’ dyslexic
students continue to experience difficulty.
It offers an explanation for the relationship between reading and memory problems.
The self-organising systems model alerts practitioners to ways in which teaching strategies
might be made more effective.
An atypical brain development framework for the study of developmental learning disabilities
The primary causes of developmental disorders are complex, involving the interaction of
genetic and environmental factors, prenatally or postnatally and primary consequences are
seen in atypical brain development (Frith, 2001). The concept of atypical brain development
may therefore offer a useful framework within which to develop theories, without being a
theory in its own right (Gilger & Kaplan, 2001; Kaplan et al., 2001). It marks an increasing
recognition that developmental disabilities are typically nonspecific and heterogeneous and
that the scientific literature shows comorbidity of symptoms and syndromes to be the rule
rather than the exception. The concept was prompted by the realisation that conventional
diagnostic categories do not reflect the way that developmental disorders affect real people,
that the co-occurrence of developmental disabilities is greater than chance and that it is
difficult to find valid subtypes of developmental problems. The framework has been proposed
in order to initiate dialogue and debate across a wide variety of disciplines. It reflects databased
theoretical developments not only in the field of learning disability but also in the wider
area of developmental disorder.
Centrally, the framework addresses the unsubstantiated assumption of ‘comorbidity’, namely
that any co-occurring symptoms have independent origins. While part of the apparent
comorbidity between diagnostic categories happens in consequence of overlapping criteria, a
greater part may be attributed to an underlying lack of specificity in the individual case. That
is to say, discrete categories do not exist in real life. Because of this, the concept of atypical
brain development has been introduced so that the data can be interpreted in a different way.
The framework challenges both the practice of ‘pigeonhole’ diagnoses and also the notion of
‘syndromes’ in developmental disorders.
Like the earlier term ‘minimal brain dysfunction’, the concept of ‘atypical brain development’
links neurology with behavioural problems. However, unlike ‘minimal brain dysfunction’, it
carries no implication of damage. Instead, it suggests that atypical development is the
extreme of a continuous normal distribution. It takes into account the lack of empirical
support for claims—prompted, possibly, by trauma studies—of simple brain localisation,
contrasting with evidence that brain imaging studies of people with learning disabilities
indicate multifocal dysfunction.