Learning problems often result from a complex interaction of child-, family-, and school-related variables. There are a variety of issues that often require a multidisciplinary approach.
The prevalence of learning disabilities is estimated to be 5% to 10% of students in school. No single cause of learning disabilities has been identified. Research has emphasized the critical importance to learning of language development and of weaknesses in processing and retrieving information (memory). This may result in a child's inability to focus attention on tasks and effectively devise problem-solving strategies.
Children with learning difficulties are more likely to be confused by sequences in time relate, to have "right-left confusion", to fail to appreciate spatial relationships and visual detail, and to have difficulty integrating auditory/ visual stimuli (e.g. sounds of words and the visual shapes of letters). These children also are more likely to be clumsy and awkward and are often subject to behavioral or emotional problems.
It is common for these children to experience difficulties with inattention, distractibility, lack of persistence, and impulsivity. All this impairs school functioning.
Signs and Symptoms
Inattention or attention deficit is the primary sign of ADD, but the patient may also display impulsivity. When overactivity is present, the syndrome is described as ADHD - attention deficit with hyperactivity disorder.
Inattention, or a short attention span, may be characterised by a number of traits, such as an obvious failure to finish tasks, easy distractibility and difficulty concentrating on longer tasks. Impulsivity may be described as impatience, acting before thinking and constantly shifting from one task to another. Hyperactivity may be recognised as a difficulty in sitting still, resulting in constant moving about, running or climbing.
Children with learning difficulties are usually very difficult to manage as toddlers and pre-schoolers and may be less responsive than peers to positive or negative reinforcement. This difficulty in management may persist into school age, when children may exhibit difficulty with motor tasks and writing skills.
These children are generally underachievers, may lack motivation, exhibit continuous movement of the lower extremities, talk impulsively, show a lack of awareness of their environment and don't consider the long term consequences of their behaviour.
- difficulty listening and thus in following directions
- difficulty focussing and sustaining attention
- poor organisational skills, frequently loses belongings
- poor motor coordination
- poor relationships with peers
- may become substance dependent and be predisposed to violence and drug abuse.
- anxiety and emotional instability
- easily distracted
- inconsistent performance at school
- often talks excessively
- difficulty remaining seated
- low tolerance -thresholds
- conduct disorders
Diagnosis
As with many syndromes, diagnosis is not clear cut, and ADD is often difficult to distinguish from other behavioural problems. A diagnostic complication is that ratings of the same children performed by a medical doctor, a neuropsychologist, a teacher or a parent, produce very different results.
Causes
The causes of and contributors to ADD are many and are still being elucidated. Dysfunctional brain and neurotransmitter involvement has been reported. Examination of glucose utilisation by various parts of the brain has revealed that ADD and ADHD sufferers have decreased metabolic activity in specific brain areas. Analysis of ADD adults showed that half of the sixty brain regions analysed demonstrated significant reduction in glucose metabolism. Those areas showing the greatest reduction are the premotor cortex, the superior prefrontal cortex and the temporal lobes. These areas are responsible for preparation and execution of motor activity, inhibition of inappropriate responses, the regulation of attention and the storage of and retrieval of information. These results clearly indicate an organic defect in these individuals.
Patients with ADD are also known to have a substantially higher incidence of thyroid hormone resistance resulting in impaired performance on an auditory discrimination task. T3, the active form of thyroxine (the hormone produced by the thyroid), is very difficult to measure accurately. Inadequate T3 activity can result in diminished brain function.
Other research indicates that there is an impairment of sympathetic nervous system activation as well as central catecholamine disregulation. This may explain why stimulant therapy is effective in ADD patients. It is also perhaps notable that noradrenaline is trophic to neural tissue and that lower levels of noradrenalin may contribute to poor brain development. Researchers have also suggested that poor nutrition may cause lowered noradrenalin levels, which is contributory to ADD.
Patients with ADD are also known to have a substantially higher incidence of thyroid hormone resistance resulting in impaired performance on an auditory discrimination task. T3, the active form of thyroxine (the hormone produced by the thyroid), is very difficult to measure accurately. Inadequate T3 activity can result in diminished brain function.
