What assessments are currently used to investigate and diagnose cerebral visual impairment (CVI) in children? A systematic review

PURPOSE

Cerebral visual impairment (CVI) is the leading cause of childhood visual impairment in the developed world. Despite this, there are no agreed clinical guidelines for the investigation and diagnosis of the condition. Before development of such guidelines can commence, it is important to recognise which approaches are currently employed. This systematic review evaluated the literature to identify which methods of assessment are currently used to investigate and diagnose childhood CVI.

METHODS

Medline, Embase, CINAHL, Scopus and the Cochrane Library databases were systematically searched in January 2020 using defined search terms. Articles were included if they: (i) were research papers, conference abstracts or research protocols published in peer-reviewed scientific journals, or relevant textbooks; (ii) included a clinical investigation of CVI in children; (iii) provided an explanation or criteria to diagnose CVI and (iv) were specifically investigating cerebral/cortical visual impairment. Methods used to a) assess and b) diagnose CVI were extracted from included articles. 'Assessment scores' were assigned for each method employed by researchers to investigate and diagnose CVI to quantify and compare approaches between articles. A quality grading was also applied to each article.

RESULTS

Of 6454 identified articles, 45 met the inclusion criteria. From these, 10 categories of assessment utilised within included articles were identified: (1) Medical history, (2) Vision assessment/ophthalmologic examination, (3) Neuroimaging, (4) Visual behaviour and direct observation, (5) Structured history-taking, (6) Visual perception tests, (7) Ocular movement and posture assessment, (8) Intelligence/IQ assessment, (9) Clinical electrophysiology and (10) Neurodevelopmental tests. In terms of diagnostic criteria, the most commonly reported approach was one of exclusion, i.e., CVI was diagnosed when visual dysfunction could not be attributed to abnormalities detected in the anterior visual pathway.

CONCLUSION

There is a lack of common practice in the approaches used by clinicians to investigate and diagnose CVI in children. At present, a 'diagnosis of exclusion' remains the most common means to diagnose CVI. Development of clinical guidelines for assessment and diagnosis are necessary to ensure consistency in the diagnosis of CVI and the timely implementation of support to alleviate the impact of CVI on the child's daily living.

Feasibility Randomized Trial for an Intensive Memory-Focused Training Program for School-Aged Children with Acquired Brain Injury

(1) Background: Memory deficits are common sequelae of pediatric Acquired Brain Injury (ABI). Only methods for non-focused cognitive remediation are available to the pediatric field. The aims of this feasibility trial are the description, implementation, and test of an intensive program specific to the training and re-adaptation of memory function in children, called Intensive Memory-Focused Training Program (IM-FTP); (2) Methods: Eleven children and adolescents with ABI (mean age at injury = 12.2 years, brain tumor survivors excluded) were clinically assessed and rehabilitated over 1-month through IM-FTP, including physio-kinesis/occupational, speech, and neuropsychology treatments. Each patient received a psychometric evaluation and a brain functional MRI at enrollment and at discharge. Ten pediatric controls with ABI (mean age at injury = 13.8 years) were clinically assessed, and rehabilitated through a standard program; (3) Results: After treatment, both groups had marked improvement in both immediate and delayed recall. IM-FTP was associated with better learning of semantically related and unrelated words, and larger improvement in immediate recall in prose memory. Imaging showed functional modification in the left frontal inferior cortex; (4) Conclusions: We described an age-independent reproducible multidisciplinary memory-focused rehabilitation protocol, which can be adapted to single patients while preserving inter-subject comparability, and is applicable up to a few months after injury. IM-FTP will now be employed in a powered clinical trial.

Visual Perceptual Skills in Attention-deficit/Hyperactivity Disorder Children: The Mediating Role of Comorbidities

SIGNIFICANCE

Attention-deficit/hyperactivity disorder (ADHD) has been commonly associated with alterations in visual perception. However, the individual behavior of visual perceptual skills and its relationship with different comorbidities remain unknown.

PURPOSE

The purpose of this study was to examine whether visual perceptual skills are impaired in children with ADHD, as well as to test the possible mediating role of comorbidities.

METHODS

Thirty-five nonmedicated ADHD (20 pure and 15 with comorbidities) and 35 age-matched controls completed the performance-based Test of Visual Perceptual Skills.

RESULTS

The analysis between total ADHD and controls favored the alternative hypothesis (greater values for children with ADHD) for visual memory, spatial relationships, sequential memory, and all the composite measures (Bayes factor [BF] range, 4.26 to 366.85). The analysis between pure ADHD and controls showed that data are more likely under the alternative hypothesis for spatial relationships, sequential memory, overall, basic, and sequencing (BF range, 3.82 to 21.71), whereas the comparison between ADHD with comorbidities and controls additionally favored the alternative hypothesis for visual discrimination (BF = 5.37). Lastly, data from the comparison between pure ADHD and ADHD with comorbidities were insensitive for favoring the null or alternative hypotheses in any subtest or composite scaled score (BF range, 0.33 to 0.66).

CONCLUSIONS

Our results suggest that some specific patterns of visual perception are altered in ADHD, especially for the total ADHD group. The current findings also evidence that comorbidities play an important role in the association between ADHD and visual perceptual skills. Future studies should address the mediating role of each specific type of comorbidity.

Does visual perceptual testing correlate with caregiver and teacher reported functional visual skill difficulties in school-aged children?

Purpose

As occupational therapists embrace evidence-informed and occupation-centred practice, the use of standardised visual perceptual tests remains a strong feature of typical paediatric practice. Yet, the research evidence for the use of such tools is inconclusive at best. This study compared the results of the Test of Visual Perceptual Skills (TVPS) with a checklist of reported functional difficulties in 30 children attending occupational therapy. The purpose of this paper was to determine the usefulness of visual perceptual testing in relation to occupation-centred practice.

Design/methodology/approach

A descriptive correlational study design was used. Participants were 30 primary school-age children who were on a paediatric occupational therapy caseload. An additional 30 typically developing children participated in the development of the checklist.

Findings

Correlations were found between reported functional visual skill difficulties and two subtests of the TVPS (visual memory and visual discrimination). No correlation was found between the reported functional difficulties and any of the other five subtests of the TVPS or the total score.

Originality/value

Results highlight the weak relationship that existed in this study between standardised measures of visual perception, as measured by the TVPS, and functional difficulties. Therapists are cautioned to explore both the evidence base for continued use of standardised visual perceptual measures to inform occupation-centred practice and the need to embrace a more comprehensive person-centred approach to visual perceptual assessment.

Visual processing in reading disorders and attention-deficit/hyperactivity disorder and its contribution to basic reading ability

Whether visual processing deficits are common in reading disorders (RD), and related to reading ability in general, has been debated for decades. The type of visual processing affected also is debated, although visual discrimination and short-term memory (STM) may be more commonly related to reading ability. Reading disorders are frequently comorbid with ADHD, and children with ADHD often have subclinical reading problems. Hence, children with ADHD were used as a comparison group in this study. ADHD and RD may be dissociated in terms of visual processing. Whereas RD may be associated with deficits in visual discrimination and STM for order, ADHD is associated with deficits in visual-spatial processing. Thus, we hypothesized that children with RD would perform worse than controls and children with ADHD only on a measure of visual discrimination and a measure of visual STM that requires memory for order. We expected all groups would perform comparably on the measure of visual STM that does not require sequential processing. We found children with RD or ADHD were commensurate to controls on measures of visual discrimination and visual STM that do not require sequential processing. In contrast, both RD groups (RD, RD/ADHD) performed worse than controls on the measure of visual STM that requires memory for order, and children with comorbid RD/ADHD performed worse than those with ADHD. In addition, of the three visual measures, only sequential visual STM predicted reading ability. Hence, our findings suggest there is a deficit in visual sequential STM that is specific to RD and is related to basic reading ability. The source of this deficit is worthy of further research, but it may include both reduced memory for order and poorer verbal mediation.

Are Motor-free Visual Perception Skill Constructs Predictive of Visual-motor Integration Skill Constructs?

Background

Theoretical perspectives vary in considering whether visual perceptual skills and visual-motor integration (VMI) skills are related, interdependent skill sets, or two discrete skill constructs.

Objective

This study investigated whether motor-reduced/free visual perceptual skill constructs were predictive of motor-enhanced VMI skill constructs.

Method

A total of 45 typically developing children aged 6–12 years completed the Developmental Test of Visual Perception-Second Edition (DTVP-2) and the Test of Visual Perceptual Skills-Third Edition (TVPS-3). Four multiple linear regression analyses were completed with the four DTVP-2 motor-enhanced VMI subscales being the dependent (criterion) variables and the seven TVPS-3 motor-reduced subscales being the independent variables.

Results

The total variance accounted for in the four DTVP-2 VMI skill constructs by all the seven TVPS-3 skill constructs ranged from 29.3% to 60.10%. In the first regression analysis, the TVPS-3 Visual Sequential Memory and TVPS-3 Visual FigureGround constructs explained 5.40% and 4.90%, respectively, of the variance in the DTVP-2 Eye Hand Coordination construct. In the second regression, the TVPS-3 Visual Sequential Memory and TVPS-3 Visual Figure–Ground constructs accounted for 5.60% and 3.10%, respectively, of the DTVP-2 Copying construct's variance. The third analysis revealed that the TVPS-3 Visual Memory and TVPS-3 Visual Form Constancy constructs represented 6.20% and 7.90%, respectively, of the DTVP-2 Spatial Relations construct's variance. In the fourth and final regression analysis, the TVPS-3 Visual Sequential Memory and TVPS-3 Visual Figure–Ground construct explained 14.60% and 4.90%, respectively, of the variance in the DTVP-2 Visual-Motor Speed construct.

Conclusion

In the four regression analyses, specific types of motor-reduced visual perception constructs were predictive of the four specific types of motor-enhanced VMI constructs. Visual Sequential Memory and Visual FigureGround, specific types of motor-reduced visual perceptual constructs, were frequent and significant predictors of VMI skill constructs in children. It would appear that motor-reduced visual perceptual skills and motor-enhanced VMI skills as theoretical constructs are related and dependent on one another.

An External Validity Study of the Visual Memory Subtest of the Test of Visual Perceptual Skills, Third Edition

Purpose:

The purpose of this study was to compare scores on the Visual Memory subtest of the Test of Visual Perceptual Skills, Third Edition, with those on a Draw-from-Memory task.

Method:

The external validity of the Visual Memory subtest was measured by comparing the subtest scores with performance on a Draw-from-Memory activity. Participants were 80 primary school age children, including 28 identified as learning disabled.

Results:

A moderate correlation (r = 0.411) was found, supporting the hypothesis that the two measures are related. However, the learning disabled children accounted for much of the covariance found, possibly due to the mix of verbal and non-verbal disabilities.

Conclusion:

The validity of the standardised test based on its correlation with a related activity was only weakly supported.

Construct Validity of the Three Motor-Reduced Subscales of the Developmental Test of Visual Perception — Adolescent and Adult (DTVP-A): A Rasch Analysis Model Evaluation

Background:

The Developmental Test of Visual Perception — Adolescent and Adult (DTVP-A) is a test used by therapists even though its construct validity has not been thoroughly assessed.

Purpose:

This study evaluated the scalability/interval level measurement, unidimensionality, lack of differential item functioning (DIF) and hierarchical ordering of the items of the three motor-free subscales (Figure-Ground, Form Constancy and Visual Closure) of the DTVP-A.

Method:

The motor-free visual perceptual performance scores from a sample of 221 participants aged 20+ years (49 adults with and 172 adults without neurological impairment) were used to complete a Rasch analysis of the DTVP-A's three motor-free subscales.

Results:

On the DTVP-A Figure-Ground (FG) subscale, items FG2 and FG6 demonstrated Rasch model misfit, while no item exhibited DIF. On the Form Constancy (FC) subscale, items FC1, FC2, FC4 and FC6 were misfitting, while items FC3 and FC11 exhibited DIF based on gender. Visual Closure (VC) subscale items VC2, VC3, VC13 and VC15 exhibited misfit with the Rasch model requirements, while VC1 and VC5 demonstrated DIF. When all three subscales were analysed together as one Total Motor-Reduced Visual Perception Scale, items FC2, FC1, FC4, VC12, VC15, FC17 and FG6 demonstrated Rasch model misfit, while items VC1, VC2, VC5 and FC11 exhibited DIF based on gender.

Conclusion:

The construct validity, scalability, hierarchical ordering and lack of DIF requirements were met by the majority of the motor-free DTVP-A items. However, items FG6, FC1, FC2, FC4 and FC11 appeared to be particularly problematic. Given the fact that a number of items exhibited Rasch analysis model misfit or DIF, clinicians need to take this into consideration when using the three motor-free DTVP-A subscales individually or collectively to assess clients.