A meta-analysis of working memory impairments in survivors of moderate-to-severe traumatic brain injury.

Abstract

Objectives: To establish the magnitude of deficits in working memory (WM) and short-term memory (STM) in those with moderate-to-severe traumatic brain injury (TBI) relative to age-matched, healthy controls and to explore the moderating effects of time since injury and age at injury on these impairments. Method: Twenty-one studies that compared the WM and/or STM abilities of individuals with at least a moderate TBI relative to healthy controls were included in a random effects meta-analysis. Measures used to examine memory performance were categorized by modality (visuospatial, verbal) and memory system (WM, STM). Results: Individuals with TBI had significant deficits in verbal STM (Cohen’s d = .41), visuospatial WM (Cohen’s d = .69), and verbal WM (Cohen’s d = .37) relative to controls. Greater decrements in verbal STM and verbal WM skills were associated with longer time postinjury. Larger deficits were observed in verbal WM abilities in individuals with older age at injury. Conclusion: Evidence for WM impairments following TBI is consistent with previous research. Larger verbal STM and verbal WM deficits were related to a longer time postinjury, suggesting that these aspects of memory do not “recover” over time and instead, individuals might show increased rates of cognitive decline. Age at injury was associated with the severity of verbal WM impairments, with larger deficits evident for injuries that occurred later in life. Further research needs to chart the long-term effects of TBI on WM and to compare the effects of injury on verbal relative to visuospatial memory.

Lindeløv et al. (2017) Improving working memory performance in brain-injured patients using hypnotic suggestion: a randomized controlled trial

“…TMT is primarily used as a visuospatial index of executive control (Sánchez-Cubillo et al, 2009), we sought to operationalize the overall working memory construct rather than the components. Positive results on both indices are necessary to claim that working memory per se improved (Baddeley, 2007;Dunning et al, 2016). However, it is interesting to note that verbal and visuospatial domains are differentially affected following TBI, with moderate-large working memory impairments on visuospatial material and small-medium impairments on verbal material for TBI patients at a median of 4.3 years post-injury as compared to healthy controls (Dunning et al, 2016)..…”

“…Working memory is a central cognitive function that enables short-term storage and manipulation of information in the face of concurrent processing (Cowan, 2005;Baddeley, 2007). There is a high prevalence of working memory impairments following acquired brain injury (Carroll et al, 2004;Cumming et al, 2013), with executive functioning being the most frequently affected component of working memory (Serino et al, 2006;Dunning et al, 2016). For TBI, the high susceptibility of working memory related regions and pathways between these regions (Shenton et al, 2012) could underly these impairments.…”

A dopamine gradient controls access to distributed working memory in monkey cortex

“…Working memory activity was disrupted most strongly by lesions to areas with a high D1 receptor density, a prediction that can be tested experimentally. Human patients with traumatic brain injury often have working memory deficits (Dunning et al 2016). Pharmacological treatment of these deficits, including with dopaminergic drugs, has seen mixed success (Froudist-Walsh et al 2017b).…”

Hypnosis for Acquired Brain Injury: Four Patient Cases and Five Testable Predictions

“…This is generally true across types of injury -from Mild Traumatic Brain Injury (sometimes called concussion) to severe strokes. Estimates point to prevalence rates around 50% for these sequelae (Carroll et al, 2004;Cumming, Marshall, & Lazar, 2013;Dunning, Westgate, & Adlam, 2016;Serino et al, 2006). Patients suffering from deficits in these domains will often complain that thinking itself has become a strenuous and unreliable activity.…”