Cognitive Reserve and Its Association with Cognitive and Mental Health Status following an Acute Spinal Cord Injury.

BACKGROUND: Mild cognitive impairment (MCI) is a common secondary condition associated with spinal cord injury (SCI). Cognitive reserve (CR) is believed to protect against cognitive decline and can be assessed by premorbid intelligence (pmIQ). Despite the potential utility of pmIQ as a complementary metric in the evaluation of MCI in SCI, this approach has been infrequently employed. The purpose of this study was to examine the association between MCI and pmIQ in adults with SCI with the aim of exploring the potential value of pmIQ as a marker of CR in this population. METHODS: Cognitive function was assessed on three occasions in adults with SCI over a 12-month period post-injury, and pmIQ was assessed once at baseline. Demographic and mental health measures were also collected, and logistic regression was conducted to determine the strength of association between pmIQ and MCI while adjusting for factors such as mental health and age. RESULTS: The regression analysis revealed that at the time of admission to SCI rehabilitation, the MCI assessed by a valid neurocognitive screen was strongly associated with pmIQ. That is, if a person has MCI, there was 5.4 greater odds (p < 0.01) that they will have poor pmIQ compared to a person without MCI after adjustment for age and mental health. CONCLUSIONS: The assessment of CR is an important area that should be considered to improve the process of diagnosing MCI in adults with an acute SCI and potentially facilitate earlier intervention to slow or prevent cognitive decline.

A Narrative Review of Research on Adjustment to Spinal Cord Injury and Mental Health: Gaps, Future Directions, and Practice Recommendations.

Spinal cord injury (SCI) results in autonomic, motor, and sensory impairments that can compromise mental health. Guidelines directing the management of mental health following SCI presently address clinical anxiety, depression, post-traumatic stress, substance use disorders, and suicide. However, evidence suggests that perhaps as many as 70% of individuals with SCI do not develop a clinically diagnosable mental health disorder. Therefore, the authors contend that understanding non-clinical cognitive and psychological aspects of adjustment post-SCI is paramount and that the application of this knowledge to the formulation of adjustment-enhancing interventions is crucial. To assist with this endeavour, we examine existing mental health guidelines targeting SCI, and present a narrative review of research on the under-represented topics of adjustment, coping, grief, and resilience. We include mild cognitive impairment, which reflects a common factor that can compromise adjustment. Loss and stress trigger processes of adjustment, coping, grief, and resilience. SCI involves loss and stress triggering these processes, arguably without exception. Our study applied a narrative review methodology searching Google Scholar and PsychInfo databases for terms adjustment, coping, grief, resilience, and cognitive impairment. Qualitative studies and quantitative studies were selected to capture bottom-up and top-down perspectives. Reference lists of retrieved papers were searched as appropriate. Reviewed literature suggested that existing guidelines concerning mental health following SCI neglect positive processes of adjustment and suggest this neglect contributes to a deficits-based view of mental health following SCI. Research into "positive" or adjustment-enhancing processes is mostly cross-sectional, heterogenous, and poorly positioned to inform future guideline-development. Researchers should achieve consensus over the operationalisation of essential processes and overcome a fixation with "outcomes" to better inform management of mental health after SCI.

Cognitive Impairment in Individuals With Spinal Cord Injury: Findings of a Systematic Review With Robust Variance and Network Meta-analyses.

BACKGROUND AND OBJECTIVES: Estimates of the prevalence (10-60%) of cognitive impairment in individuals with spinal cord injury (SCI) are too broad and which domains of cognition are most affected is unclear. We performed a meta-analysis to investigate impairments across domains of cognitive functioning to provide a nuanced picture of research conducted to date into cognitive impairment following SCI. METHODS: Results of peer reviewed studies published in English between 1980 and 2021 comparing ≥20 participants with SCI to able-bodied controls were synthesized using meta-analysis. The primary outcomes were neurocognitive test scores categorized into five cognitive domains as listed in the Diagnostic and Statistical Manual of Mental Disorders: Complex Attention, Executive Functioning, Learning and Memory, Language, and Perceptual Motor Function. Two researchers independently assessed and verified extracted data to comply with meta-analytic reporting guidelines. Robust variance estimation (RVE) meta-analysis was conducted to determine an overall pooled effect size across all cognitive domains using data extracted from studies. Using network meta-analysis, we synthesised eligible studies and made comparisons with the five domains of cognitive functioning serving as the outcomes and SCI as the condition. RESULTS: Of 4,783 potential studies, 13 met final inclusion criteria. Studies met 6 of 8 quality assessment criteria generally. Results suggested that adults with SCI have reduced cognitive functioning (effect size:-0.84; 95%CI: -1.24, -0.44, p < .001) compared to able-bodied individuals, with deficits mostly in attention (g= -0.64; 95%CI: -0.92, -0.38) and executive functioning (g= -0.61, 95%CI: -0.89, -0.04). Publication bias and high heterogeneity (I2:86%) qualify these findings and highlight the need to improve research methods in this area. DISCUSSION: Adults with SCI appear more likely than adults who are able-bodied to display cognitive impairments mostly in areas of attention and executive functioning. Research practices must become consistent to reduce heterogeneity so that the validity and reliability of the results of future studies into cognitive impairment following SCI improves.

The Need for a Specialized Neurocognitive Screen and Consistent Cognitive Impairment Criteria in Spinal Cord Injury: Analysis of the Suitability of the Neuropsychiatry Unit Cognitive Assessment Tool.

The assessment of mild cognitive impairment (MCI) following spinal cord injury (SCI) is vital. However, there are no neurocognitive screens which have been developed specifically to meet the unique requirements for SCI, nor are there consistent MCI criteria applied to determine the rates of MCI. The aim of this study was to determine the suitability of a neurocognitive screen for assessing MCI in adults with SCI. A total of 127 participants were recruited. Socio-demographic and injury related variables were assessed. All participants completed the screen. Descriptive statistics are provided for total/domain screen scores and all items, and the screen's ability to distinguish MCI was examined. Congeneric confirmatory factor analyses (CFA) were employed to investigate structural validity. The screen total score was sensitive to differences in neurocognitive capacity, as well as for time since the injury occurred (p < 0.01). The MCI rate ranged between 17−36%. CFA revealed attention and visuoconstruction domains had an adequate model fit and executive function had poor fit, while CFA models for memory and language did not fit the data (did not converge), hence could not be determined. While the screen differentiated between those with MCI and those without, and MCI as a function of time since injury, limitations of its suitability for assessing MCI after SCI exist, demonstrating the need for a specialized neurocognitive screen for adults with SCI.

Improving Assessment of Cognitive Impairment after Spinal Cord Injury: Methods to Reduce the Risk of Reporting False Positives.

Adults with spinal cord injury (SCI) are reported to have heightened risk of cognitive impairment, notably mild cognitive impairment (MCI). Reports of increased risk of MCI are almost exclusively based on cross-sectional assessments of cognitive function using norm-referenced scores. Norm-referenced single-point assessments do not reflect cognitive decline at the individual level but rather represent between group differences in cognitive function. The practice of relying solely on norm-referenced assessment to study MCI after SCI is therefore problematic as it lends to potential misclassification of MCI. Premorbid intelligence estimates permit comparison of people's actual versus expected cognitive function and thereby can be used to validate the presence of genuine cognitive decline. These are not utilized in the assessment of MCI after SCI. This study simulated data for 500,000 adults with SCI to compare norm-referenced and premorbid-intelligence methods of screening for MCI to examine the potential extent of MCI misclassification after SCI resulting from the overreliance on norm-referenced methods and exclusion of premorbid intelligence methods. One in five to one in 13 simulated adults with SCI were potentially misclassified as having MCI showing that measures of premorbid cognitive function must be included in assessment of cognitive function after SCI.

A prospective cohort study investigating contributors to mild cognitive impairment in adults with spinal cord injury: study protocol.

BACKGROUND: Studies report rates of mild cognitive impairment (MCI) in spinal cord injury (SCI) range between 10 and 60%. This broad estimate of MCI in SCI is most likely a result of: (i) inconsistent operationalization of MCI; (ii) heterogeneity among individuals with SCI; (iii) failure to account for MCI subtypes, thereby adding to the heterogeneity of samples; and, (iv) poor control for traumatic brain injury (TBI) that obscures differentiation of MCI attributable to TBI versus other factors. There is a paucity of longitudinal studies following the course of MCI in SCI, and none that account for multiple predictors of MCI, including interactions among predictors. METHODS: An inception cohort longitudinal study will assess approximately 100 individuals aged 17-80 years with acute SCI, with measures taken at three timepoints (baseline, 3 months post-baseline, and 12 months post-injury). Data relevant to medical care received within the first 24-48 h of presentation to the emergency department will be analysed, as will measures of cognition, injury characteristics, medical history, personal factors, psychological status, psychosocial functioning, and quality of life. Latent class mixture modelling will determine trajectories for the primary outcome of interest, cognitive functioning and its subtypes, and secondary outcomes of interest such as depression. Multiple regression analyses will identify predictors of MCI and its subtypes. DISCUSSION: The prospective design will reveal change in cognitive functioning across time and unveil different outcome trajectories; thus addressing the lack of knowledge on trajectories of MCI and MCI subtypes in SCI. Through subtyping MCI, we hope to yield groups of cognitively impaired individuals with SCI that are potentially more homogenous and thereby stable and predictable. This is the first study to capture emergency department and acute care diagnostic evidence of mild TBI, which has been poorly controlled in previous studies. Our study will also be the first to distinguish the contribution of TBI from other factors to the development of MCI in individuals with SCI. TRIAL REGISTRATION: The study was prospectively registered with the Australian and New Zealand Clinical Trial Registry ( ACTRN12619001702101 ) on 3rd December 2019.