Neuropsychiatric Symptoms of Epilepsy

13 Attention, Executive Function, and Attention Deficit Hyperactivity Disorder
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Risk Factors for ADHD in Children with Epilepsy
There are several potential explanations for the comorbidity of epilepsy and ADHD,
disorders of attention, or deficits in executive functioning. There may be concurrent
comorbidity in which both epilepsy and impaired attention and executive function
are due to a common underlying problem. Alternatively, the association may be due
to successive comorbidity in which either epilepsy or ADHD causes or creates a
vulnerability to developing the other condition. There are several potential explanations
for problems with attention and executive functioning (see Table 13.1 ).
Concurrent Comorbidity
Suggestive evidence for concurrent comorbidity comes from studies that show
symptoms of ADHD present prior to or at the onset of seizures and from studies
demonstrating a bidirectional association between epilepsy and ADHD. Populationbased
surveys have shown that children with ADHD have over twice the risk of
developing seizures than controls. Chou et al. [ 20 ] followed 3664 children and adolescents
with ADHD and 14,522 age matched controls for 3–3.5 years. The incidence
of epilepsy was 3.24 % in the ADHD sample in 0.78 % in controls for a
hazard ratio of 3.94 (95 % CI 2.58–6.03). Hesdorrfer et al. [ 64 ] noted that the association
between ADHD and subsequent epilepsy existed for ADHD predominantly
inattentive type but not for ADHD combined or hyperactive-impulsive types. Davis
et al. [ 65 ] used data from the Rochester Epidemiology Project to compare children
with ADHD to controls. The children found with ADHD were 2.7 times more likely
to develop epilepsy than controls. The children with ADHD developed seizures earlier
and had more severe seizures than controls with epilepsy, and the children with
ADHD and epilepsy were less likely to receive treatment for ADHD than those with
ADHD alone.
Several studies have obtained EEGs in patients with ADHD and found focal
spikes in approximately 5–10 % of recordings [ 66 – 70 ]. Two studies of new-onset
seizures found evidence of ADHD prior to first seizure. Austin et al. [ 71 ] noted
symptoms of ADHD in 10.7 % of children with new-onset seizures compared to 3.0
Table 13.1 Risk factors for
problems with attention and
executive function and
ADHD
Risk factors for problems with
attention and executive function and
ADHD
1. Common genetic vulnerability
2. Central nervous system damage
3. Early age of seizure onset
4. Severe or frequent seizures
5. Frequent epileptiform discharges
6. Adverse effect of antiepileptic drugs