Dyslexia
This widely discussed form of learning disability is a specific problem with cognition.
The broadest definition of dyslexia includes those children whose reading skills are
delayed for any reason, and it is usually associated with a number of cognitive
deficits. Prevalence varies from 3% to 16% depending on the breadth of the definition
and the country. For example, prevalence rates are higher in the United States than
they are in Italy, perhaps due to the complexity of the English language as compared
with Italian!
Minimal brain damage
This category of impairment is used to describe the child who has minor neurological
signs, which are often transitory. They are not reliable predictors of future behavioural
and educational problems.
Attention disorder and hyperactivity
These disorders are often confused with one another. Children who cannot sit still are
thought to be inattentive to their lessons in school. A child who does not pay attention
often: fails to finish activities; acts prematurely or redundantly; infrequently reacts to
requests and questions; has difficulties with tasks that require fine discrimination,
sustained vigilance, or complex organization; and improves markedly when
supervised intensively. A child who is hyperactive: engages in excessive standing up,
walking, running, and climbing; does not remain seated for long during tasks;
frequently makes redundant movements; shifts excessively from one activity to
another; and/or often starts talking, asking, or making requests. This elevated activity
level expresses itself differently at different ages. Inattentive, hyperactive children are
disturbing to their parents, other children, and to professionals like teachers, doctors,
and dentists. They are often judged to be behaviourally disturbed. The variation in
definition, age, sex, source of the data, and cultural factors produces prevalence
estimates of up to 35%. However, most estimates are under 9% for boys and even less
for girls.
Emotional and behavioural disorders
There are many manifestations of emotional disorder: fear, anxiety, shyness,
aggressive, destructive or chronically disobedient behaviour, theft, associating with
bad companions, and truancy. When parents or teachers believe that these problems
interfere with the child's socialization, they are often referred for professional help. In
considering the prevalence of emotional or behavioural disorders, account has to be
taken of the very common, seemingly identical, behaviour of normal children. Eating
disorders, which may be of concern to dentists because of self injurious behaviour as
well as dental erosion, are important in the preschool period and, in different ways, in
adolescence.