Evidence of nonverbal learning disability among learning disabled boys with sensory integrative dysfunction

Systematic Review: Nonverbal Learning Disability

OBJECTIVE

To summarize the current state of the research literature on nonverbal learning disability (NVLD), including criteria used to define NVLD in research contexts and the quality of the extant research; and to determine what research can tell us about ways in which NVLD is distinct from DSM neurodevelopmental disorders and typical development.

METHOD

A systematic search of 7 databases was conducted to identify research on NVLD published through February 2019. Criteria used to define NVLD were extracted from identified studies and sorted by category. Each study was assessed for risk of bias and rated "good," "fair," or "poor;" findings from studies rated good or fair were summarized.

RESULTS

A total of 61 articles (63 studies) met inclusion criteria. There was great heterogeneity in the criteria used to define NVLD. Deficits in visuospatial ability/intelligence was the most common criterion used, followed by discrepancy between verbal and nonverbal intelligence (VIQ>PIQ split of 10 or greater). All studies were cross-sectional and most included small, poorly described samples. Most studies focused on children and young adolescents. Eight studies were rated as good, 42 as fair, and 13 as poor. Review of results from the 50 good or fair studies suggest that there is sufficient evidence that youths with NVLD (as defined by significant deficits in visuospatial abilities) can be clearly differentiated from their typically developing peers, those with verbal learning disorders, and from other clinical groups (eg, individuals with high functioning autism).

CONCLUSION

A standard set of criteria for determining an NVLD diagnosis would greatly improve research studies and the possibility of inclusion in the DSM and the International Classification of Diseases.

Evidence review to investigate the support for subtypes of children with difficulty processing and integrating sensory information

We investigated the evidence for subtypes in children with difficulty processing and integrating sensory information. Fifty-seven articles were incorporated into a systematic literature review; only 4 articles provided direct evidence for subtypes. These studies did not provide a comprehensive assessment of all sensory functions and sensory-based motor functions (i.e., praxis) and included different diagnostic groups. Therefore, generalized conclusions about subtypes could not be drawn. The other 53 studies reviewed provided meaningful information about strengths and challenges that children with difficulty processing and integrating sensory information demonstrate, but these studies were limited in scope. A principal theme was the importance of conducting comprehensive assessments of sensory-based functions, including multiple measures of sensory integrative functions such as praxis, sensory modulation, and sensory discrimination in children and adolescents with various clinical disorders. In addition, more consistency in the use of specific assessment tools will allow for synthesis of data across studies.

Motor control alteration in posturography in learning-disabled children

BACKGROUND

Some authors have mentioned that intersensory integration is damaged in children with learning disabilities (LDs), and other investigators point to motor control alterations in the same patients. Thus, we decided to study these hypotheses by means of posturographic recordings.

METHODS

A highly selected group of 27 children with LDs was compared with 27 children of control group without LDs. Patients and controls were placed on the Equitest equipment platform. Sensory organization tests evaluated different test conditions that systematically vary visual, vestibular, and foot somatosensory cues available to subjects while they attempt to maintain a stable, quiet stance. Movement coordination test involved sudden posterior and anterior translations of the patient support surface.

RESULTS

No significant correlations between scholastics and posturographic performance were observed. No difference in the six conditions and in sensory organization ratios or in visual preference between both groups was disclosed. Motor control test on children with LDs showed significant higher values in latencies in averages of large translations.

CONCLUSIONS

Our data suggest that vestibular-visual-somatosensory organization for posture control are not abnormal in children with LDs; instead, motor controls show higher latencies with large translation movements, which suggest abnormal rate and timing precision motor coordination.

Spatial and emotional aspects of language inferencing in nonverbal learning disabilities

Although subtle linguistic deficits have been postulated for children identified with nonverbal learning disabilities (NLD), there is little empirical evidence to support this contention. Two experimental language inferencing measures that have been demonstrated to be problematic for individuals with right hemisphere brain damage (RHBD) and one norm-referenced inferencing task were examined in three groups of children aged 9-13: (1) children with NLD (n = 14), (2) children with verbal impairments (VI) (n = 14), and (3) children without learning disabilities who served as controls (n = 19). The NLD and VI groups did not differ from one another on any of the three measures, indicating a generalized language inferencing deficit in the NLD group. Relative to the control group, however, the NLD group experienced specific difficulties with spatial and emotional inferencing. The implications for right hemisphere involvement in the NLD profile are examined in relation to the effects of working memory on inferential abilities.