Comparing Canadian and American normative scores on the Wechsler Adult Intelligence Scale-Fourth Edition

Special Series on the Wechsler Adult Intelligence Scale-IV Performances in Five Asian Countries: Summary of Findings, Clinical Implications, and Future Directions

INTRODUCTION

This special series of exploratory studies compared WAIS-IV performances in five Asian countries: Japan, South Korea, Taiwan, India, and Indonesia with the U.S. The studies examined cognitive profiles across age groups to develop hypotheses on how culture can impact cognition. This summary article integrates the findings from each study to determine similarities and differences across Asian countries and proposes possible underlying cultural factors impacting cognition.

METHODS

In each study, raw scores corresponding to a subscale score of 10 were scored with U.S. norms across all age groups. Index scores were calculated with the adjusted scale scores. The impact of education on test performances was determined by correlating WAIS-IV scores with a ratio of educational attainment for each country with the U.S. for each age group. Findings from each country were then integrated to develop hypotheses on cultural factors that impacted cognitive profiles.

RESULTS

East Asian countries (Japan, South Korea, Taiwan) demonstrated weaker Verbal Comprehension Index scores and stronger Processing Speed Index scores than the U.S. sample, although the latter was moderated by age. East Asian countries demonstrated stronger performances on Perceptual Reasoning versus Verbal Comprehension tests. East Asians and the Java subset of the Indonesian sample demonstrated a pattern of stronger performances in younger versus older cohorts which was significantly correlated with educational attainment.

DISCUSSION

Cultural factors impacting cognition were proposed. Clinical implications of the findings were discussed and directions for future studies to examine the relationship between culture and cognition were recommended.

Performance of the Social Responsiveness Scale-2 for the Assessment of Autistic Behaviors in a Sample of Canadian Preschool-Aged Children

Behavioral traits of autism spectrum disorder (ASD) typically present in early childhood, underscoring the importance of screening tools for the early identification of ASD. The current study compared scores on the Social Responsiveness Scale-Second Edition (SRS-2) Preschool Form between the US standardization sample (n = 247) and a Canadian cohort of preschool-aged children (n = 595) recruited from the Maternal-Infant Research on Environmental Chemicals (MIREC) study. In the MIREC sample, we examined whether ASD-like traits are correlated with sociodemographic characteristics and child intellectual abilities, and how maternal ratings of social skills assessed by the SRS-2 are associated with maternal ratings of general problem behaviors. Mean total SRS-2 raw score was significantly lower in the MIREC sample (mean = 29.7, SD = 15.8) compared to the US standardization sample (mean = 41.9, SD = 26.0). Total raw score in the US standardization sample did not significantly differ between males (mean = 40.6, SD = 23.1) and females (mean = 42.8, SD = 28.7), whereas in the MIREC sample the total raw score was significantly higher among males (mean = 33.0, SD = 17.1) than females (mean = 26.6, SD = 13.9). A significantly larger proportion of the MIREC sample was White, younger in age, and had more educated parents compared to the US standardization sample. ASD-like traits were correlated with lower intellectual abilities, a less enriched home environment, more behavioral problems, and poorer adaptive skills. SRS-2 Preschool Form scores were significantly lower in the Canadian sample compared to the US standardization sample, which may reflect demographic differences between the two groups. Girls may be under-identified when SRS-2 Preschool Form norms are used for screening ASD.

Risks associated with cognitive function and management strategies in the clinical use of ADT: a systematic review from clinical and preclinical studies

Prostate cancer is one of the most common malignancies and a leading cause of death in men. Owing to its excellent anti-tumor effects, androgen deprivation therapy (ADT) is widely used in the treatment of prostate cancer. However, its use is controversial because of its potential for inducing cognitive decline. In this review, we summarized the findings of preclinical and clinical studies investigating the effects of ADT on cognitive function in prostate cancer. We discussed the methods used to assess cognitive function in these studies, elucidated the mechanisms through which ADT affects cognitive function, and highlighted recent advancements in cognitive assessment methods. The findings of this review serve as a valuable reference for examining the relationship between ADT and cognitive function in future studies. Besides, the findings may help clinicians understand the advantages and disadvantages of ADT and optimize the treatment plan so as to minimize the adverse effects of ADT.

Genetic Factors and Long-term Treatment-Related Neurocognitive Deficits, Anxiety, and Depression in Childhood Leukemia Survivors: An Exome-Wide Association Study

BACKGROUND

An increased risk of neurocognitive deficits, anxiety, and depression has been reported in childhood cancer survivors.

METHODS

We analyzed associations of neurocognitive deficits, as well as anxiety and depression, with common and rare genetic variants derived from whole-exome sequencing data of acute lymphoblastic leukemia (ALL) survivors from the PETALE cohort. In addition, significant associations were assessed using stratified and multivariable analyses. Next, top-ranking common associations were analyzed in an independent SJLIFE replication cohort of ALL survivors.

RESULTS

Significant associations were identified in the entire discovery cohort (N = 229) between the AK8 gene and changes in neurocognitive function, whereas PTPRZ1, MUC16, TNRC6C-AS1 were associated with anxiety. Following stratification according to sex, the ZNF382 gene was linked to a neurocognitive deficit in males, whereas APOL2 and C6orf165 were associated with anxiety and EXO5 with depression. Following stratification according to prognostic risk groups, the modulatory effect of rare variants on depression was additionally found in the CYP2W1 and PCMTD1 genes. In the replication SJLIFE cohort (N = 688), the male-specific association in the ZNF382 gene was not significant; however, a P value<0.05 was observed when the entire SJLIFE cohort was analyzed. ZNF382 was significant in males in the combined cohorts as shown by meta-analyses as well as the depression-associated gene EXO5.

CONCLUSIONS

Further research is needed to confirm whether the current findings, along with other known risk factors, may be valuable in identifying patients at increased risk of these long-term complications.

IMPACT

Our results suggest that specific genes may be related to increased neuropsychological consequences.

Characterizing mild cognitive impairment to predict incident dementia in adults with bipolar disorder: What should the benchmark be?

Objective: Although mild cognitive impairment (MCI) is generally considered a risk state for dementia, its prevalence and association with dementia are impacted by the number of tests and cut-points used to assess cognition and define "impairment," and sources of norms. Here, we investigate how these methodological variations impact estimates of incident dementia in adults with bipolar disorder (BD), a vulnerable population with pre-existing cognitive deficits and increased dementia risk. Method: Neuropsychological data from 148 adults with BD and 13,610 healthy controls (HC) were drawn from the National Alzheimer's Coordinating Center. BD participants' scores were standardized against published norms and again using regression-based norms generated from HC within the same catchment area as individual BD patients ("site-specific norms"), varying the number of within-domain tests (one vs. two) and the cut-points (-1 vs. -1.5 SD) used to operationalize MCI. Results: Site-specific norms were more sensitive to incident dementia (88.6%-94.3%) than published norms (74.3%-88.6%), but only when using a "single test" definition of impairment. Specificity (22.1%-74.3%), accuracy (37.8%-68.9%), and positive predictive values (26.1%-38.3%) were overall poor. Applying a "single test" definition of impairment resulted in better negative predictive values using site-specific (92.3%-93.3%) than published norms (83.6%-86.2%), and a substantial increase in relative risk of incident dementia relative to published norms. Conclusions: Neuropsychologists should define "impairment" as scores below -1.0 or -1.5 SD on at least two within-domain measures when using published norms to interpret cognitive performance in adults with BD.

IQ After Pediatric Concussion

OBJECTIVES

This study investigated IQ scores in pediatric concussion (ie, mild traumatic brain injury) versus orthopedic injury.

METHODS

Children (N = 866; aged 8-16.99 years) were recruited for 2 prospective cohort studies from emergency departments at children's hospitals (2 sites in the United States and 5 in Canada) ≤48 hours after sustaining a concussion or orthopedic injury. They completed IQ and performance validity testing postacutely (3-18 days postinjury; United States) or 3 months postinjury (Canada). Group differences in IQ scores were examined using 3 complementary statistical approaches (linear modeling, Bayesian, and multigroup factor analysis) in children performing above cutoffs on validity testing.

RESULTS

Linear models showed small group differences in full-scale IQ (d [95% confidence interval] = 0.13 [0.00-0.26]) and matrix reasoning (0.16 [0.03-0.30]), but not in vocabulary scores. IQ scores were not related to previous concussion, acute clinical features, injury mechanism, a validated clinical risk score, pre- or postinjury symptom ratings, litigation, or symptomatic status at 1 month postinjury. Bayesian models provided moderate to very strong evidence against group differences in IQ scores (Bayes factor 0.02-0.23). Multigroup factor analysis further demonstrated strict measurement invariance, indicating group equivalence in factor structure of the IQ test and latent variable means.

CONCLUSIONS

Across multisite, prospective study cohorts, 3 complementary statistical models provided no evidence of clinically meaningful differences in IQ scores after pediatric concussion. Instead, overall results provided strong evidence against reduced intelligence in the first few weeks to months after pediatric concussion.

Relationships of Motor Changes with Cognitive and Neuropsychiatric Features in FMR1 Male Carriers Affected with Fragile X-Associated Tremor/Ataxia Syndrome

The premutation expansion of the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene on the X chromosome has been linked to a range of clinical and subclinical features. Nearly half of men with FMR1 premutation develop a neurodegenerative disorder; Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS). In this syndrome, cognitive executive decline and psychiatric changes may co-occur with major motor features, and in this study, we explored the interrelationships between these three domains in a sample of adult males affected with FXTAS. A sample of 23 adult males aged between 48 and 80 years (mean = 62.3; SD = 8.8), carrying premutation expansions between 45 and 118 CGG repeats, and affected with FXTAS, were included in this study. We employed a battery of cognitive assessments, two standard motor rating scales, and two self-reported measures of psychiatric symptoms. When controlling for age and/or educational level, where appropriate, there were highly significant correlations between motor rating score for ICARS gait domain, and the scores representing global cognitive decline (ACE-III), processing speed (SDMT), immediate memory (Digit Span), and depression and anxiety scores derived from both SCL90 and DASS instruments. Remarkably, close relationships of UPDRS scores, representing the contribution of Parkinsonism to FXTAS phenotypes, were exclusive to psychiatric scores. Highly significant relationships between CGG repeat size and most scores for three phenotypic domains suggest a close tracking with genetic liability. These findings of relationships between a constellation of phenotypic domains in male PM carriers with FXTAS are reminiscent of other conditions associated with disruption to cerebro-cerebellar circuits.

Neurocognitive Profiles Associated With Limited English Proficiency in Cognitively Intact Adults

OBJECTIVE

The objective of the present study was to examine the neurocognitive profiles associated with limited English proficiency (LEP).

METHOD

A brief neuropsychological battery including measures with high (HVM) and low verbal mediation (LVM) was administered to 80 university students: 40 native speakers of English (NSEs) and 40 with LEP.

RESULTS

Consistent with previous research, individuals with LEP performed more poorly on HVM measures and equivalent to NSEs on LVM measures-with some notable exceptions.

CONCLUSIONS

Low scores on HVM tests should not be interpreted as evidence of acquired cognitive impairment in individuals with LEP, because these measures may systematically underestimate cognitive ability in this population. These findings have important clinical and educational implications.

A Systematic Review and Comparison of Neurocognitive Features of Late-Life Attention-Deficit/Hyperactivity Disorder and Dementia With Lewy Bodies

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) in adulthood and dementia with Lewy bodies (DLB) share many cognitive and noncognitive similarities. The overlapping features between both disorders complicate differential diagnosis. The aim of the current systematic review was to compare patterns of neuropsychological profiles in older adults with ADHD and DLB.

METHOD

Of the 1989 ADHD-related articles and 1332 DLB-related articles screened, 3 ADHD and 25 DLB articles were retained for qualitative synthesis and review.

RESULTS

A synthesis of individual study findings revealed isolated working memory deficits for late-life ADHD, and performance deficits in areas of attention, memory, language, and visuoperceptual abilities for DLB. Results were limited by small samples and absence of data in some cognitive domains.

CONCLUSION

These initial findings support potentially unique neurocognitive profiles for ADHD in later life and DLB that would enable practitioners to differentially diagnose and appropriately treat older adults presenting with these phenotypically similar disorders.

Clinical neuropsychology in Canada: results from the 2020 AACN, NAN, SCN professional practice and "salary survey"

Objective: The current study summarizes the results of a 2020 survey that solicited information regarding backgrounds, beliefs, practices, and incomes of clinical neuropsychologists who practice in Canada. Methods: Clinical neuropsychologists who practice in Canada were invited to participate in an online survey that was available from 1/17/20 to 4/02/20. Available survey findings were obtained from 111 respondents, which reflects a response rate of 51.3% of the 216 doctoral-level Canadian neuropsychologists identified in at least one major North American or international professional organization membership list (AACN, INS, NAN, or SCN). Results: Most of the current respondents were White/Caucasian women who identified as adult providers and worked full-time in urban institutional settings. Four Canadian provinces (Alberta, British Columbia, Ontario, Quebec) accounted for more than 91% of the current respondent sample. Incomes and career satisfactions were largely encouraging, though some important variations were noted by province, work setting, and professional identity. Incomes were significantly associated with forensic practices and years of clinical experience. Most respondents made use of technician support in their practices, largely to increase productivity and patient volume. Only a small minority of respondents were board-certified and there was generally limited interest in future board certification. Conclusions: While important similarities were observed in the current Canadian sample relative to recent survey findings obtained in a U.S. sample, results also reveal a number of important differences that serve as important areas of future consideration.

Delineating the Relationships Between Motor, Cognitive-Executive and Psychiatric Symptoms in Female FMR1 Premutation Carriers

Introduction: Premutation expansions (55-200 CGG repeats) of the Fragile X Mental Retardation 1 (FMR1) gene on the X chromosome are associated with a range of clinical features. Apart from the most severe - Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) - where the most typical white matter changes affect cerebellar peduncles, more subtle changes may include impairment of executive functioning, affective disorders and/or subtle motor changes. Here we aimed to examine whether performance in selected components of executive functioning is associated with subclinical psychiatric symptoms in non-FXTAS, adult females carrying the FMR1 premutation. Methods and Sample: A total of 47 female premutation carriers (sub-symptomatic for FXTAS) of wide age range (26-77 years; M = 50.3; SD = 10.9) were assessed using standard neuropsychological tests, three motor rating scales and self-reported measures of psychiatric symptoms using the Symptom Checklist-90-Revised (SCL-90-R). Results: After adjusting for age and educational level where appropriate, both non-verbal reasoning and response inhibition as assessed on the Stroop task (i.e., the ability to resolve cognitive interference) were associated with a range of primary psychiatric symptom dimensions, and response inhibition uniquely predicted some primary symptoms and global psychiatric features. Importantly, lower scores (worse performance) in response inhibition were also strongly correlated with higher (worse) scores on standard motor rating scales for tremor-ataxia and for parkinsonism. Conclusion: These results provide evidence for the importance of response inhibition in the manifestation of psychiatric symptoms and subtle tremor-ataxia motor features, suggestive of the presence of early cerebellar changes in female premutation carriers.

Sport Concussion Assessment Tool: Fifth Edition Normative Reference Values for Professional Rugby Union Players

OBJECTIVE

To describe distributions and establish normative ranges for new or changed subcomponents of the Sports Concussion Assessment Tool (SCAT)-5.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

Professional Rugby Union players performing 2017 preseason baseline SCAT-5 testing.

INDEPENDENT VARIABLES

Subcomponent tests newly introduced or changed in the SCAT-5.

MAIN MEASUREMENTS

The 10-word immediate and delayed recall tests and the rapid neurological screen.

RESULTS

Thousand two hundred three players were included in complete case analyses. The 10-word immediate recall test [median score 15, interquartile range (IQR) 15-22, range 3-30] showed an asymmetrical, bimodal distribution. The delayed recall test (median score 7, IQR 5-9, range 0-10) demonstrated a left skewed distribution. The diplopia and reading/following instruction tests of the neurological screen were performed normally by virtually all participants (98.5% and 99.6%, respectively). Normative classification ranges for each SCAT-5 subcomponents of interest were determined.

CONCLUSIONS

The increased spread of scores, with improved midrange centering, suggests that the increase to 10-word list lengths should improve the performance of immediate and delayed recall tests. Normative ranges will provide a distribution against which postinjury SCAT-5 scores can be compared and interpreted.

Remembering the past to live better in the future: A feasibility randomised controlled trial of memory specificity training for motivation in psychosis

BACKGROUND AND OBJECTIVES

People with a diagnosis of psychosis often experience low motivation and reduced activity levels. Autobiographical memory deficits have been identified in people with psychosis and this may limit the role of memory retrieval in supporting motivation. This pilot study adapted a recently developed protocol, Memflex, which aims to enhance autobiographical memory and has shown promise in depression. Our brief intervention targets experiential negative symptoms of psychosis using supported autobiographical memory retrieval.

METHOD

A sample of 31 participants with psychosis were recruited from inpatient and community settings and randomised in a 2:1 ratio to either a basic recall control or an enhanced recall intervention group. Participants were asked to generate positive autobiographical memories linked to activities they wish to repeat in the future. The enhanced recall condition received additional prompts from the Memflex protocol, and the basic recall condition received no additional support.

RESULTS

The intervention delivered was acceptable (rated >80%) and feasible (94% adherence) to those who took part. Participants were able to generate positive autobiographical memories linked to their goals and experienced appropriate emotions linked to these. The controlled preliminary effect sizes (0.2-0.34) showed encouraging signals for self-efficacy, motivation and a reduction in negative mood.

LIMITATIONS

As this was a pilot study with a small sample size between-group tests of statistical significance were not conducted, and therefore findings should be interpreted with caution.

CONCLUSIONS

These findings suggest that guided autobiographical memory retrieval may be an effective way tool for targeting motivation in people with psychosis.

Operationalizing Impaired Performance in Neuropsychological Assessment: A Comparison of the Use of Published Versus Sample-Based Normative Data for the Prediction of Dementia

OBJECTIVES

To compare the sensitivity, specificity, and predictive value of published versus sample-based norms to detect early dementia in the Uniform Data Set (UDS).

METHODS

The UDS was administered to 526 nondemented participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Baseline scores were standardized using published norms and healthy control data from ADNI corrected for age, education, and sex. Subjects obtaining two scores < -1 SD (determined separately using published and sample norms) were labeled "at risk for dementia." Both methods were compared on sensitivity, specificity, and positive/negative predictive value (PPV/NPV) for dementia at follow-up.

RESULTS

Risk scores derived from published data had 86.1% sensitivity, 62.0% specificity, 68.6% accuracy, 46.1% PPV, and 92.2% NPV. Those from sample norms were more sensitive (91.0%), less specific (52.9%), and less accurate (63.3%), with worse PPV (42.1%) and similar NPV (94.0%). Sample norms were better at identifying incident dementia cases with relatively lower education than those with higher education. Discrepancies between both methods were more common in women.

CONCLUSIONS

Sample norms are marginally more sensitive than published norms for predicting dementia, while published norms are slightly more accurate. Accuracy of risk estimates for women and those with lower education may be increased using locally generated norms.

Contributing Towards a Cultural Neuropsychology Assessment Decision-Making Framework: Comparison of WAIS-IV Norms from Colombia, Chile, Mexico, Spain, United States, and Canada

OBJECTIVE

Test and normative data selection in cross-cultural neuropsychology remain a complex issue. Despite growing awareness, more studies and instruments are needed to adequately address the impact of cultural factors, such as quantity and quality of education. In this study, we examine the interpretive effects of applying six relevant WAIS-IV norms to a Colombian sample.

METHOD

A sample of 305 highly educated Colombian corporate executives completed the WAIS-IV. Data were scored using norms from Colombia, Chile, Mexico, Spain, United States, and Canada and scores were compared using ANOVA. Additionally, a comparative sociodemographic framework was established to contextualize our sample to the standardization samples and populations of the six countries.

RESULTS

Colombian and Chilean norms yielded systematically similar FSIQ/Index scores (mean range = 117-121), while incrementally lower scores were found with norms from Mexico (-3-9 points), Spain (-3-11 points), USA (-8-13 points), and Canada (-11-18 points). Verbal scores differed, with highest scores obtained with Mexican and Spanish norms. Working memory and processing speed scores had the lowest score agreement across norms.

CONCLUSIONS

Although the Chilean norms are more frequently used in Colombia, the recently developed Colombian norms appear optimal for our sample; the scores do not have meaningful differences with those obtained with Chilean norms and offer local population representation fidelity. Mexican, Spanish, US, and Canadian norms underestimated WAIS-IV scores and distorted the sample's score distribution. Finally, verbal scores highlight potential education representation within Spanish and Mexican norms, while working memory and processing speed scores suggest cultural nuances likely captured within different norms.

Experiences, mental well-being and community-based care needs of fathers of late preterm infants: A mixed-methods pilot study

Aims

We explore fathers' experience of caring for a late preterm infant including their stressors, needs and corresponding interventions proffered by public health nurses.

Design

Pilot mixed-methods exploratory sequential design.

Methods

We collected (a) qualitative data from semi-structured interviews (N = 5) and (b) quantitative data (N = 31) about fathers' levels of stress (Parenting Stress Index), anxiety (Speilberger State-Trait Anxiety) and depression (Edinburgh Postnatal Depression Scale) at 6-8 weeks after birth of their infant.

Results

Fathers appreciated their infant was born 'early', however, discovered through experience the demands of their infant, which appeared as stress (child and parent domains) and anxiety. Themes: hypervigilance in care explained the fathers' sense of competency and role restriction; infant fatigue and parental feeding elucidated the stressful aspect of father-infant interaction. Unscientific advice from healthcare providers was confusing and frustrating while uncertainty of rehospitalization caused worries, fears or stress. One father experienced depressive symptoms.

Influence of genetic factors on long-term treatment related neurocognitive complications, and on anxiety and depression in survivors of childhood acute lymphoblastic leukemia: The Petale study

BACKGROUND

A substantial number of survivors of childhood acute lymphoblastic leukemia suffer from treatment-related late adverse effects including neurocognitive impairment. While multiple studies have described neurocognitive outcomes in childhood acute lymphoblastic leukemia (ALL) survivors, relatively few have investigated their association with individual genetic constitution.

METHODS

To further address this issue, genetic variants located in 99 genes relevant to the effects of anticancer drugs and in 360 genes implicated in nervous system function and predicted to affect protein function, were pooled from whole exome sequencing data of childhood ALL survivors (PETALE cohort) and analyzed for an association with neurocognitive complications, as well as with anxiety and depression. Variants that sustained correction for multiple testing were genotyped in entire cohort (n = 236) and analyzed with same outcomes.

RESULTS

Common variants in MTR, PPARA, ABCC3, CALML5, CACNB2 and PCDHB10 genes were associated with deficits in neurocognitive tests performance, whereas a variant in SLCO1B1 and EPHA5 genes was associated with anxiety and depression. Majority of associations were modulated by intensity of treatment. Associated variants were further analyzed in an independent SJLIFE cohort of 545 ALL survivors. Two variants, rs1805087 in methionine synthase, MTR and rs58225473 in voltage-dependent calcium channel protein encoding gene, CACNB2 are of particular interest, since associations of borderline significance were found in replication cohort and remain significant in combined discovery and replication groups (OR = 1.5, 95% CI, 1-2.3; p = 0.04 and; OR = 3.7, 95% CI, 1.25-11; p = 0.01, respectively). Variant rs4149056 in SLCO1B1 gene also deserves further attention since previously shown to affect methotrexate clearance and short-term toxicity in ALL patients.

CONCLUSIONS

Current findings can help understanding of the influence of genetic component on long-term neurocognitive impairment. Further studies are needed to confirm whether identified variants may be useful in identifying survivors at increased risk of these complications.

Anterior Temporal Lobe Morphometry Predicts Categorization Ability

Categorization is the mental operation by which the brain classifies objects and events. It is classically assessed using semantic and non-semantic matching or sorting tasks. These tasks show a high variability in performance across healthy controls and the cerebral bases supporting this variability remain unknown. In this study we performed a voxel-based morphometry study to explore the relationships between semantic and shape categorization tasks and brain morphometric differences in 50 controls. We found significant correlation between categorization performance and the volume of the gray matter in the right anterior middle and inferior temporal gyri. Semantic categorization tasks were associated with more rostral temporal regions than shape categorization tasks. A significant relationship was also shown between white matter volume in the right temporal lobe and performance in the semantic tasks. Tractography revealed that this white matter region involved several projection and association fibers, including the arcuate fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and inferior longitudinal fasciculus. These results suggest that categorization abilities are supported by the anterior portion of the right temporal lobe and its interaction with other areas.

Sport concussion assessment tool-Third edition normative reference values for professional Rugby Union players

OBJECTIVES

To establish normative reference data for the SCAT3 in professional Rugby Union players.

DESIGN

A cross sectional study in professional Rugby Union players competing in national and international professional competitions between 2015 and 2016.

METHODS

The SCAT3 was administered pre-season or prior to tournaments. Data was collected electronically using a custom tablet application. SCAT3 subcomponents distributions were described and normative ranges determined using percentile cut-offs for average, unusually low/high, and extremely low/high scores. The association between player characteristics and performance in SCAT3 subcomponents was also investigated in exploratory analyses.

RESULTS

A total of 3611 professional Rugby Union players were included. The most common baseline symptom was fatigue (14%). The symptom score median (md) was 0 (interquartile range (IQR)=0-1). Symptom severity md was 0 (IQR=0-1). The md of the SAC score was 28 (IQR=26-29). The md of the MBESS was 2 (IQR=0-4). The Tandem gait md was 11.1s (IQR=10.0-12.7s). Upper limb coordination was normal in 98.4%. Younger age and lower educational level were associated with worse performance on delayed recall and reverse month sub-components of the SCAT3 (p<0.0001). No statistically significant differences in SCAT3 subcomponents were evident across gender.

CONCLUSIONS

Representative normative reference values for the SCAT3 among professional Rugby Union players are provided. Baseline performance on concentration and delayed recall tests may be lower in younger athletes or in those with lower educational level.

Clinical neuropsychology practice and training in Canada

OBJECTIVE

This invited paper provides information about professional neuropsychology issues in Canada and is part of a special issue addressing international perspectives on education, training, and practice in clinical neuropsychology.

METHOD

Information was gathered from literature searches and personal communication with other neuropsychologists in Canada.

RESULTS

Canada has a rich neuropsychological history. Neuropsychologists typically have doctoral-level education including relevant coursework and supervised practical experience. Licensure requirements vary across the 10 provinces and there are regional differences in salary. While training at the graduate and internship level mirrors that of our American colleagues, completion of a two-year postdoctoral fellowship in neuropsychology is not required to obtain employment in many settings and there are few postdoctoral training programs in this country. The majority of neuropsychologists are employed in institutional settings (e.g. hospitals, universities, rehabilitation facilities), with a growing number entering private practice or other settings. There are challenges in providing neuropsychological services to the diverse Canadian population and a need for assessment measures and normative data in multiple languages.

CONCLUSIONS

Canadian neuropsychologists face important challenges in defining ourselves as distinct from other professions and other psychologists, in maintaining funding for high-quality training and research, in establishing neuropsychology-specific training and practice standards at the provincial or national level, and ensuring the clinical care that we provide is efficient and effective in meeting the needs of our patient populations and consumers, both within and outside of the publically funded health care system.

Impaired or Not Impaired, That Is the Question: Navigating the Challenges Associated with Using Canadian Normative Data in a Comprehensive Test Battery That Contains American Tests

It has been well documented that IQ scores calculated using Canadian norms are generally 2-5 points lower than those calculated using American norms on the Wechsler IQ scales. However, recent findings have demonstrated that the difference may be significantly larger for individuals with certain demographic characteristics, and this has prompted discussion about the appropriateness of using the Canadian normative system with a clinical population in Canada. This study compared the interpretive effects of applying the American and Canadian normative systems in a clinical sample. We used a multivariate analysis of variance (ANOVA) to calculate differences between IQ and Index scores in a clinical sample, and mixed model ANOVAs to assess the pattern of differences across age and ability level. As expected, Full Scale IQ scores calculated using Canadian norms were systematically lower than those calculated using American norms, but differences were significantly larger for individuals classified as having extremely low or borderline intellectual functioning when compared with those who scored in the average range. Implications of clinically different conclusions for up to 52.8% of patients based on these discrepancies highlight a unique dilemma facing Canadian clinicians, and underscore the need for caution when choosing a normative system with which to interpret WAIS-IV results in the context of a neuropsychological test battery in Canada. Based on these findings, we offer guidelines for best practice for Canadian clinicians when interpreting data from neuropsychological test batteries that include different normative systems, and suggestions to assist with future test development.

Getting Back to the Main Point

Miller et al. have challenged the findings of our two previous studies, based largely on the assumption that our findings are biased due to the clinical sample used. However, they fail to address the primary tenet of our studies, namely, that clinicians will obtain different scores on the Wechsler Adult Intelligence Scale-IV (WAIS-IV) depending on whether Canadian or American norms are used. This reply seeks to provide empirical evidence supporting the existence of such score differences even when nonclinical samples are used, and identifies some of the clinical decisions that are potentially affected by choice of normative data.

Intelligent Use of Intelligence Tests

It is well established that Canadians produce higher raw scores than their U.S. counterparts on intellectual assessments. As a result of these differences in ability along with smaller variability in the population’s intellectual performance, Canadian normative data will yield lower standard scores for most raw score points compared to U.S. norms. Two recent studies have questioned the utility of the WAIS–IV Canadian norms based on the performance of a mixed clinical sample of post-secondary students. These studies suggest that a greater proportion of cases from their mixed clinical samples fall below a full-scale IQ of 85 using the WAIS–IV Canadian norms than should be “expected.” The purpose of the current study is threefold: First, to summarize the consistent finding of Canada–U.S. differences on measures of ability and present new empirical analyses to demonstrate these results are not due to a smaller sample size for Canadian norms. Second, and most importantly, matched sample comparisons demonstrate that the proportion of low scoring individuals (FSIQ < 85) in mixed clinical samples is consistent with the rates published by recent studies, and not greater than expected. Third, we offer evidence-based advice to clinicians practicing in Canada on the appropriate use of Canadian norms for Canadian clients during an individual assessment of intellectual functioning.

Implications for Educational Classification and Psychological Diagnoses Using the Wechsler Adult Intelligence Scale–Fourth Edition With Canadian Versus American Norms

Building on a recent work of Harrison, Armstrong, Harrison, Iverson and Lange which suggested that Wechsler Adult Intelligence Scale–Fourth Edition (WAIS-IV) scores might systematically overestimate the severity of intellectual impairments if Canadian norms are used, the present study examined differences between Canadian and American derived WAIS-IV scores from 861 postsecondary students attending school across the province of Ontario, Canada. This broader data set confirmed a trend whereby individuals’ raw scores systematically produced lower standardized scores through the use of Canadian as opposed to American norms. The differences do not appear to be due to cultural, educational, or population differences, as participants acted as their own controls. The ramifications of utilizing the different norms were examined with regard to psychoeducational assessments and educational placement decisions particularly with respect to the diagnoses of Learning Disability and Intellectual Disability.