Novack et al.

(1996)

USA

RCT

PEDro=5

N=44

Population: Severe TBI; Focused Stimulation Group (n=22): Mean Age=28.7yr; Mean Time Post Injury=5.9wk. Unstructured Stimulation Group (n=22): Mean Age=26.4yr; Mean Time Post Injury=6.4wk

Intervention: Participants were randomly placed into a focused or unstructured stimulation group. Patients in the focused group received hierarchical attentional learning training (30min, 5x/wk). Skills were not taught in a hierarchical or sequential fashion in the unstructured group.

Outcome Measure: Digit Span and Mental Control subtests of Wechsler Memory Scale-Revised (WMS-R), computer-based simple and choice reaction time tests. Secondary outcome measures: Logical Memory I & II, Sentence Repetition, Judgment of Line Orientation, Trail Making A & B, Arithmetic subtest Wide Range Achievement Test-Revised, Visual imperceptions.

1.        Analysis of primary outcome measures revealed no significant differences between the focused and unstructured stimulation groups, both at baseline and discharge.

2.        There was a significant time effect with participants performing significantly better at the time of discharge than on admission (p<0.0001).

3.        There were no significant differences between the groups with respect to any secondary outcome measures studied.

Lindelov et al. (2016)

Denmark

PCT

N_Initial=78

N_Final=35

Population: ABI Group (n=17): Mean Age=56.1yr; Gender: Male=13, Female=4; Mean Time Post Injury=57d. Healthy Group (n=18): Mean Age=56.1yr; Gender: Male=8, Female=10.

Treatment: ABI and healthy participants were randomized and analyzed separately. Experimental group participants received 20 sessions of N-back training (N-back), where participants press a key when presented stimulus is identical to the stimulus N back in the sequence. Control group participants received 20 sessions of visual search training (VS), where participants press a key if a target symbol is present in an NxN array of symbols.

Outcome Measure: Raven’s Advanced Progressive Matrices (RAPM), Wechsler Adult Intelligence Scale-IV (WAIS-IV), Working Memory Index (WMI Index, digit span, arithmetic, letter-number sequencing), Operation Span Test (OSPAN), WAIS-IV Processing Speed Index (PSI index, search, coding), Stroop Test.

1.        Both ABI and healthy groups showed significant improvement post-intervention on the assigned training tasks (Bayes factor >> 1000). The standardized mean difference was 0.45 for ABI N-back, 6.11 for healthy N-back, 1.06 for ABI VS, and 3.34 for Healthy VS. The healthy group showed greater improvement than the ABI group (Bayes factor >> 1000).

2.        No significant differences in improvements between N-back and VS treatments (time x treatment interaction) were found in ABI or healthy groups for WMI-digit span, WMI-arithmetic, WMI-letter-number sequencing, WMI index, PSI-search, PSI-coding, PSI index, RAPM, OSPAN, or Stroop.

3.        No significant differences in improvement between healthy and ABI groups (group x time x test interaction) were found for WMI-digit span, WMI-arithmetic, WMI-letter-number sequencing, WMI index, PSI-search, PSI-coding, PSI index, RAPM, OSPAN, or Stroop.