How relevant is higher-order language deficit (HOLD) to children with complex presentations of attention-deficit hyperactivity disorder?

Attention-deficit hyperactivity disorder (ADHD) is frequently associated with language impairment, autism spectrum disorder (ASD) symptoms and higher-order language deficit (HOLD); yet, their complex relationship is poorly understood. HOLD encompasses deficits in using language for reasoning, problem-solving, causal and critical thinking. This study evaluates the roles of HOLD in children with ADHD. We hypothesise that both our subgroups (ADHD-only and ADHD + 'ASD traits') will have HOLD difficulties, though to a differing degree, as children with ADHD are compromised by executive function deficits, and those with additional ASD traits are further impaired by pragmatic language deficits. Data were reviewed from 36 children with ADHD (± 'ASD traits'), who attended the tier 4 statewide specialist clinic for ADHD patients non-responsive to community care. HOLD was assessed by the Test of Problem Solving-3 Elementary (TOPS-3). The age of the sample ranged from 6 to 12 years with a male-to-female ratio of 8:1. The rate of HOLD in our sample was 47.2% (published controls = 16%). Likewise, the rates of Making Inferences (50.0%, p < 0.001), Sequencing (44.4%, p < 0.001), Negative Questions (33.3%, p = 0.278), Problem-Solving (38.9%, p = 0.022), Predicting (27.8%, p = 0.022) and Determining Causes (30.6%, p = 0.022) were all elevated. When stratified, the rates in ADHD-only group and ADHD + 'ASD traits' group were 37.5% and 55.0%, respectively. Children with ADHD + 'ASD traits' had greater 'Sequencing' deficit. Our exploratory study confirms that HOLD is more common in children with ADHD, including deficits in Making Inferences, Sequencing, Problem-Solving, Predicting, Determining Causes and understanding Negative Questions. Our findings provide preliminary support for the potentially important role played by HOLD in neurodevelopmental disorders.