Does working memory training lead to generalised gains in children - - PowerPoint PPT Presentation

Does working memory training lead to generalised gains in children with a traumatic brain injury?

Darren Dunning

What is Traumatic Brain Injury (TBI)?

• A TBI is any brain injury caused by an external force
• It is the most common Acquired Brain Injury (ABI)

– ABI includes stroke, encephalitis, tumour, etc.

• TBI is a leading cause of death by accident with 50,000

fatalities per year in the US

– 2.5 million TBIs per year

What is Traumatic Brain Injury (TBI)?

• The severity of TBIs varies

– mild – moderate – Severe

• Long‐term outcome for those that have had a mild injury is

relatively good (e.g. Carroll, et al., 2004).

• More Severe injuries often lead to

– emotional problems (e.g. aggression, depression, etc.) – cognitive deficits in memory and attention

Meta-analysis

(Dunning, Westgate & Adlam, in prep)

• Conducted a meta‐analysis of WM and TBI because:

– Many studies that have looked at WM and TBI are by clinicians and have small samples – Studies often conflate measures of STM with WM – Many studies do not include ‘healthy’ comparison groups – WM not a unitary system, but consists of multiple interacting subcomponents that contribute differentially to different WM

• tasks. No one had looked at these WM subcomponents in detail

in a TBI group

Literature search

• Inclusion criteria:

– Moderate/severe TBI – The study used at least one measure of WM or STM – The study compared its TBI group against a healthy‐aged matched comparison group

• 17 studies included

A Model of Working Memory

Visuo-spatial Sketchpad Phonological Loop Central Executive Baddeley & Hitch (1974)

Results

NB: If a study used multiple measures of an aspect of memory, then effect sizes were averaged (e.g. For composite WM all WM tasks were averaged regardless of if the were verbal or visuo‐spatial)

Table 1. Meta‐analyses of working memory components between individuals that have survived a traumatic brain injury and normal controls

• No. of

subjects

• No. of

studies TBI HC Mean effect size (d) z 95% CI I2 (95% CI) Verbal STM 8 270 238 0.41 3.96* [0.21 ‐ 0.57] 17.52 Visuo‐spatial STM 4 124 89 0.23 1.65 [‐0.04 ‐ 0.51] Verbal WM 15 381 356 0.70 6.07* [0.47 ‐ 0.93] 50.42 Visuo‐spatial WM 4 188 128 0.60 1.92 [0.31 ‐ 0.77] 83.97 Short‐term memory 9 289 238 0.41 3.74* [0.21 ‐ 0.56] 27.73 Working memory 16 451 396 0.69 6.89* [0.49 ‐ 0.77] 42.61 Verbal memory 17 515 417 0.65 6.33* [0.43 ‐ 0.71] 46.54 Visuo‐spatial memory 5 194 129 0.47 3.53* [0.21 ‐ 0.74] 18.50 NB: TBI = traumatic brain injury; HC = healthy controls; CI = confidence intervals *p<.001

Meta-regression

Study name Std diff in means and 95% CI Gorman, et al. (2012) Lecerq, et al. (2000) Azouvi et al. (2004) Levin, et al. (2002) Vallet-Avouzi, et al. (2007) Anderson & Knight (2010) Willmott, et al. (2009) Chapman, et al. (2006) Christodoulou, et al. (2001) Perlstein, et al. (2004) Slovarp, et al. (2012) Moran & Gillon (2004) Perbal, et al. (2003) Perlstein, et al. (2006) Kim, et al. (2012)

• 2.00
• 1.00

0.00 1.00 2.00

Meta-regression

• To explore differences in effect sizes, two moderator variables

were examined : – Time since TBI – Age TBI occurred

Results

• WM v STM for age at Injury

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 50 100 150 Std diff in means Time since injury Series1 Linear (Series1)

Regression of Age at injury on Std diff in means

Age at injury Std diff in means

4.62 8.32 12.01 15.71 19.40 23.10 26.80 30.49 34.19 37.88 41.58 2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 50 100 150 200 Std diff in means Time since injury (months) Series1 Linear (Series1)

Regression of age at injury on Std diff in means

age at injury Std diff in means

4.36 7.06 9.76 12.46 15.16 17.86 20.55 23.25 25.95 28.65 31.35 0.80 0.72 0.64 0.56 0.48 0.40 0.32 0.24 0.16 0.08 0.00

Working Memory (p= <.01) Short‐term memory (p=.80)

Results

• WM v STM for time since injury

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 50 100 150 Std diff in means Time since injury Series1 Linear (Series1)

Regression of Age at injury on Std diff in means

Age at injury Std diff in means

4.62 8.32 12.01 15.71 19.40 23.10 26.80 30.49 34.19 37.88 41.58 2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00

Regression of Time since injury on Std diff in means

Time since injury Std diff in means

• 14.26

4.05 22.36 40.68 58.99 77.30 95.61 113.92 132.24 150.55 168.86 2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 50 100 150 200 Std diff in means Time since injury (months) Series1 Linear (Series1)

Regression of age at injury on Std diff in means

age at injury Std diff in means

4.36 7.06 9.76 12.46 15.16 17.86 20.55 23.25 25.95 28.65 31.35 0.80 0.72 0.64 0.56 0.48 0.40 0.32 0.24 0.16 0.08 0.00

Regression of time since injury on Std diff in means

time since injury Std diff in means

• 6.56

10.91 28.38 45.86 63.33 80.80 98.27 115.74 133.22 150.69 168.16 0.80 0.72 0.64 0.56 0.48 0.40 0.32 0.24 0.16 0.08 0.00

Working Memory (p= .20) Short‐term memory (p=.20)

Interim conclusions

• TBI individuals have pronounced deficits in WM when compared to

healthy, age‐matched controls.

• Deficits in STM less pronounced
• In TBI individuals, deficits in WM (but not STM) are greater when

the TBI occurs at an older age.

• Deficits in verbal abilities greater when TBI occurs at an older age.
• Why?

– STM v WM – WM more attentionally demanding?

Rationale for RCT

• Children that have survived a TBI often have cognitive

impairments including WM deficits that impact on their schooling.

• No previous Cogmed studies with TBI individuals or brain

injured children.

Yr Sample Control group? Gains?

Björkdahl, et al. 2013 20 adults (ABI) 18 Digit span, rivermead NB: no improvement on BDR Johansson & Tornmalm 2012 18 adults (ABI) X Trained tasks Lundqvist, et al. 2010 11 adults (ABI) 10 Trained tasks, neuro WM task Westerberg, et al. 2007 9 adults (stroke) 9 Span board

An RCT of Working Memory Training in children with TBI

• 90 Children aged between 8 – 16 years: 11 months

– Moderate-severe TBI – 6 months post injury

• Exclusion criteria

– Evidence of motor/ visual impairment – Use of medication affecting memory – Premorbid diagnosis of learning disability – Previous WM training – Lacks the capacity to assent/ consent

The children are referred to us from one of the following sites

• Addenbrookes’
• Cambridge Centre for Paediatric Neuropsychological Rehabilitation
• Norfolk & Norwich Hospital
• West Suffolk Hospital
• Child Brain Injury Trust
• Frenchay Hospital
• Royal Devon & Exeter Hospital
• Cambridgeshire Community Services
• Norfolk & Waveney

Design

• Children are screened on IQ and two tests of working memory. If

they score in the bottom 30th centile on one of the working memory measures then they can be included in the study.

• Children are then assessed on an extensive range of measures of

learning, behaviour, etc.

• Allocated to group (stratified by age and IQ)

Active intervention (adaptive working memory training) Active control (non-adaptive working memory training)

However...

An RCT of Working Memory Training in children with TBI ABI

• 29 children screened

– 16 children trained:

• 10 adaptive training
• 6 non‐adaptive training

– 6 currently training – 3 waiting to train (undergoing pre‐assessment) – 2 dropped out after screening – 2 did not meet inclusion criteria

• Baseline data entered for first 22 participants
• 15 boys, 7 girls
• Mean age 12yrs, 3mths
• Mean deficits in:
• Performance IQ (but not verbal IQ)
• Short‐term memory
• Working memory (AWMA, BRIEF)
• Long‐term memory (Rey, CMS)
• Attention (dual task)
• Switching (letter‐number)
• Mathematics (but not reading comprehension)

Trial updates

• Mean deficits in (contd):
• Inattention
• Hyperactivity
• Executive functions
• Learning
• Aggression
• Peer problems
• Inhibition
• Emotional control
• Initiate
• Planning
• Organisation of materials
• Monitoring

Trial updates

Some notes on those that have trained

• Training is taking longer than expected, especially for the

adaptive condition

• Average 9 weeks for adaptive condition

– Shortest 5 weeks, Longest 20 weeks

• Average 7.8 weeks for non‐adaptive condition

– Shortest 5 weeks, Longest 13 weeks

• Average gain is 19 points on Cogmed index

– Average in US for children aged 7‐17 is 28

Conclusion

• So far there has been difficulty recruiting a childhood TBI

group

• In this very early stage of data collection no group differences
• n the memory measures
• It is taking longer for the brain injured children to complete

Cogmed and their gains are a little below what would be expected

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