DOI: 10.1177/23969415261465246 ISSN: 2396-9415

Adaptive Functioning in Expressively Nonverbal and Minimally Verbal Autistic Children: Nonverbal Intelligence as a Predictive Factor

Ekaine Rodríguez-Armendariz, Zuriñe Ábalos, Elena Castroviejo, Agustín Vicente
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Background and Aims

Adaptive functioning is a strong predictor of long-term outcomes for autistic individuals, yet evidence regarding its association with ADOS-2 comparison scores, nonverbal IQ (NVIQ), and early language development remains inconsistent. Findings on the contributions of IQ and ADOS-2 comparison scores are mixed, and early linguistic abilities have received comparatively less attention. This study examined how receptive language delay, NVIQ, and ADOS-2 comparison scores relate to later adaptivity in nonverbal and minimally verbal autistic children.

Methods

Participants were 4- to 12-year-old autistic children ( N  = 44) who completed ADOS-2 Module 1 at baseline, indicating limited expressive language but variability in age and developmental profiles. Baseline assessments included ADOS-2 comparison scores, NVIQ (Leiter-3), and receptive vocabulary (PPVT-III). Adaptive functioning was measured 2 to 3 years later using Vineland-3 subscales. To examine the contribution of each variable, we fitted multiple linear regression models with Vineland-3 scores as the dependent variable and standardized test scores as continuous predictors, while controlling for children's age (in months) and the testing interval between the ADOS-2 and the Vineland-3. We first fitted separate models for each predictor, followed by additive models including the three predictors. Additional models included interaction terms between NVIQ and ADOS-2 comparison scores, PPVT-III scores and ADOS-2 scores, NVIQ and PPVT-III scores, and their three-way interaction. Model comparisons were conducted to determine which model provided a better fit for the data.

Results

NVIQ emerged as the only significant predictor of adaptive functioning. Although ADOS-2 comparison scores and receptive vocabulary were significantly associated with adaptivity in the simpler models, these effects were no longer significant once NVIQ was included, suggesting that their predictive value was largely accounted for by NVIQ. Unlike earlier reports, higher NVIQ in this sample was not associated with greater adaptive difficulties, which suggests this relationship is not uniform across subgroups of autistic children. Interaction analyses did not reveal significant moderation effects, although some interactions involving NVIQ or receptive language delay and ADOS-2 approached conventional significance thresholds. These effects require confirmation in larger samples.

Conclusions

Adaptive functioning in autistic children with limited expressive language abilities is predicted more strongly by NVIQ than by ADOS-2 comparison scores, receptive language delay or the interaction of these three variables.

Implications

These findings indicate that early NVIQ remains a meaningful predictor of adaptive functioning in minimally verbal autistic children, underscoring the importance of including nonverbal cognitive assessments in early prognostic evaluations. The absence of meaningful associations with ADOS-2 comparison scores and receptive vocabulary delay when NVIQ was accounted for suggests that adaptive outcomes may depend less on trait profile or linguistic comprehension than may be assumed, and that autistic children may successfully compensate for early marked autistic traits and comprehension difficulties.

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