Poster #1 - A Latent Profile Analysis of Executive Functions: Associations with Academic and Behavioural Outcomes

• In Event: 1-005 - Poster Session 01
  In Poster Session: PS 01 Section - Attention, Learning, Memory

Integrative Statement

Objectives: Individuals with neurodevelopmental disorders including ADHD are thought to have deficits in executive functions (EFs) in comparison to their typically developing peers. Research examining EFs in neurodevelopmental disorders has focused primarily on group differences (e.g., typically developing versus clinical subgroups) rather than focusing on heterogeneity in EF performance regardless of clinical diagnoses. This study used Latent Profile Analyses (LPA) to empirically identify profiles of EF performance and the associations between these profiles and clinical markers and characteristics. Moreover, we explored whether age interacted with EF profile; and expected that older children with EF deficit profiles would show greater impairment due to increased incremental impact over time.

Methods: The sample included 424 youth, aged 6-16 years (M = 10.06, SD = 2.43), enriched with cases referred for neurodevelopmental concerns. Youth without known impairments were included to provide a full spectrum of EF traits and clinical presentations. Confirmatory factor analysis (CFA) was used to assess the dimensionality of four working memory (WM) tasks (verbal and spatial tasks within span and Nback paradigms). An LPA included WM factor scores from the CFA and three additional EF measures - reaction time, variability, response inhibition- to identify unique patterns of EF performance correcting for age. Profiles were compared across internalizing and externalizing clinical traits, language and academic outcomes. Profiles were also stratified by age (i.e., <10years and >10years) for developmental comparisons within, and across, each of the EF profiles.

Results: The LPA identified three groups: 1) no EF deficits, 2) WM-specific EF deficits, and 3) multiple EF deficits with poor WM, reaction time, variability and response inhibition (see Table 1). Groups did not differ on anxiety. The two profiles with EF deficits had the highest proportion of youth with elevated ADHD symptoms, however >40% of cases with no EF deficits met criteria for ADHD. All groups presented with moderate to high severity on an index of global impairment. The no EF deficit group significantly outperformed the groups with EF deficits F(10,478) = , p < .001; Pillai’s Trace = .140 across all language and academic outcomes. Differences were also observed between the WM-specific and multiple-deficit groups for math and language (p <.05 to <.01). Older participants in each profile showed the greatest academic, language, and behavioral deficits, particularly among those in the multiple EF deficit profile (see Figure 1).

Conclusions: Results are consistent with research showing EF deficits among many but not all individuals with ADHD. Additional variation in clinical presentation was related to the EF profiles. When compared to similar performing peers, differences within EF profiles suggested that older youth had greater impairments, especially within the multiple-deficit profile. Results suggest that the impairment associated with EF deficits may become more severe with maturation, arguing for the importance of early intervention to support children with EF deficits. Understanding EF profiles within the broader range of neurodevelopmental disorders may help to identify varying levels of impairment and provide additional information to guide targeted intervention above and beyond clinical diagnosis.

Authors

• Kimberley C Tsujimoto, Ontario Institute for Studies in Education/University of Toronto
  Presenting Author

• Rhonda L Martinussen, University of Toronto
  Non-Presenting Author

• Russell Schachar, The Hospital for Sick Children
  Non-Presenting Author

• Jennifer Crosbie, The Hospital for Sick Children
  Non-Presenting Author