Cognitive reserve index and functional and cognitive outcomes in severe acquired brain injury: A pilot study

The utility of the Cognitive Reserve Index questionnaire in chronic traumatic brain injury

Objective: This study examined the relationship between cognitive reserve measured with the Cognitive Reserve Index questionnaire (CRIq) and cognitive and functional outcomes in a chronic traumatic brain injury (TBI) cohort compared to a non-TBI cohort. The utility of the CRIq was compared to common proxies of cognitive reserve (premorbid IQ and years of education) in TBI and non-TBI cohorts. Method: Participants were 105 individuals with moderate-severe TBI (10-33 years post injury) and 91 participants without TBI. Cognitive outcome was examined across four cognitive factors; verbal memory, visual ability and memory, executive attention, and episodic memory. Functional outcome was measured using the Glasgow Outcome Scale Extended. The CRIq total score and three subscale scores (education, work, leisure) were examined. Results: In the TBI cohort, associations were identified between two CRIq subscales and cognitive factors (CRIq education and verbal memory; CRIq work and executive attention). There were no associations between CRIq leisure and cognitive outcomes, or between CRIq and functional outcome. Model selection statistics suggested premorbid IQ and years of education provided a better fit than the CRIq for the relationship between cognitive reserve with two cognitive factors and functional outcome, with neither model providing an improved fit for the remaining two cognitive factors. This finding was broadly consistent in the non-TBI cohort. Conclusion: Cognitive reserve contributes significantly to long-term clinical outcomes following moderate-severe TBI. The relationship between cognitive reserve and long-term cognitive and functional outcomes following TBI is best characterised with traditional proxies of cognitive reserve, mainly premorbid IQ, rather than the CRIq.

Cognitive reserve index and long-term disability in patients with severe traumatic brain injury discharged from the intensive rehabilitation unit

Objectives

The "cognitive reserve" (CR) theory posits that higher premorbid cognitive activities can mitigate the effects of brain damage. This study aimed to investigate the association between CR and long-term functional autonomy in patients surviving a severe traumatic brain injury (sTBI).

Setting

Data were collected from the database of inpatients with severe acquired brain injury in a rehabilitation unit admitted from August 2012 to May 2020.

Participants

Patients that had incurred an sTBI, aged 18+ years, completing the phone Glasgow Outcome Scale-Expanded at follow-up (pGOS-E) in absence of previous brain trauma or neurological disease, or cognitive disorders were included. Patients with severe brain injury from non-traumatic etiologies were not included in the study.

Design

In this longitudinal study, all patients underwent a multidimensional assessment including the cognitive reserve index questionnaire (CRIq), the coma recovery scale-revised, the level of cognitive functioning, the Disability Rating Scale (DRS), and the Galveston Orientation and Amnesia Test at admission. At discharge, functional scales were administered again together with the Glasgow Outcome Scale. The pGOS-E was assessed at follow-up.

Main measures

pGOS-E.

Results

A total of 106 patients/caregivers underwent the pGOS-E after 5.8 [3.6] years from the event. Among them, 46 (43.4%) died after discharge, and 60 patients [men: 48 (80%); median age: 54 years; median time post-onset: 37 days; median education level: 10 years; median CRIq total score: 91] were included in the analysis exploring the association between pGOS-E and demographic data, cognitive reserve surrogates, and clinical variables at admission and discharge from the rehabilitation unit. A younger age (B = -0.035, p = 0.004) and a lower DRS category at discharge (B = -0.392, p = 0.029) were significantly related to a higher long-term functional autonomy in the multivariate analysis.

Conclusion

Long-term functional autonomy was not influenced by CR as assessed through the educational level and the CRIq.

The moderating effect of cognitive reserve on cognitive function in patients with Acute Ischemic Stroke

Background

Recovery of cognitive function after stroke has inter-individual variability. The theory of cognitive reserve offers a potential explanation of the variability in cognitive function after stroke.

Objective

This study aimed to investigate the moderating effect of cognitive reserve on the relationship between the stroke severity and cognitive function after stroke.

Materials and methods

A total of 220 patients with Acute Ischemic Stroke (AIS) were recruited in 2021 from two stroke centers in Nanjing, China. The National Institutes of Health Stroke Scale (NIHSS) was used to assess stroke severity upon admission. Cognitive Reserve Index questionnaire (CRIq) and validated Montreal Cognitive Assessment, Changsha Version (MoCA-CS) were used to assess cognitive reserve and cognitive function within 7 days after stroke onset, respectively. A series of multivariate linear regression models were applied to test the moderating effect of cognitive reserve.

Results

Patients with a higher level of cognitive reserve had better cognitive function after stroke compared with those with a lower level of cognitive reserve (β = 0.074, p = 0.003). The interaction of NIHSS and cognitive reserve was statistically significant (β = −0.010, p = 0.045) after adjusting for some key covariates [e.g., age, marital status, Oxfordshire Community Stroke Project (OCSP) classification, Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification, cerebral vascular stenosis, diabetes and atrial fibrillation].

Conclusion

Cognitive reserve may help to buffer the effect of stroke-related pathology on cognitive decline in Chinese acute stroke patients. Enhancing cognitive reserve in stroke patients may be one of the potential strategies for preventing vascular dementia.

The Assessment of Cognitive Reserve: A Systematic Review of the Most Used Quantitative Measurement Methods of Cognitive Reserve for Aging

The cognitive reserve (CR) is widely accepted as the active ability to cope with brain damage, using preexisting cognitive and compensatory processes. The common CR proxies used are the number of formal years of education, intelligence quotient (IQ) or premorbid functioning, occupation attainment, and participation in leisure activities. More recently, it has employed the level of literacy and engagement in high-level cognitive demand of professional activities. This study aims to identify and summarize published methodologies to assess the CR quantitatively. We searched for published studies on PubMed, ScienceDirect, and Web of Science between September 2018 and September 2021. We only included those studies that characterized the CR assessment methodology. The search strategy identified 1,285 publications, of which 25 were included. Most of the instruments targeted proxies individually. The lack of a gold standard tool that incorporates all proxies and cognitive tests highlights the need to develop a more holistic battery for the quantitative assessment of CR. Further studies should focus on a quantitative methodology that includes all these proxies supported by normative data to improve the use of CR as a valid measure in clinical contexts.

The Turkish translation study of the Cognitive Reserve Index Questionnaire (CRIq)

BACKGROUND

Cognitive reserve (CR) is defined as the ability of individuals to use their brain in a flexible way to cope with brain pathologies and find alternative cognitive strategies.

AIM

The aim of this study was to adapt Cognitive Reserve Index Questionnaire (CRIq) for Turkish population.

METHODS

The CRIq was administered to 178 healthy participants from 18 to 80 years old.

RESULTS

The mean score of total CRI was found to be 97.7 indicating a medium level of CR. In line with the mean score, 68.6% of participants (n = 120) were found to have a medium level of CRI. The elderly group showed lowest total CRI as well as CRI-education, CRI-work, and CRI-leisure scores compared to young and middle-aged groups (p < .05, for all scores).

CONCLUSIONS

This study provided the first translated measure to assess CR in Turkish population.