Effects of Bromocriptine on Executive Functioning

Author/Year/ Country/Study design/PEDro/ N

 

Methods

 

Outcome

Whyte et al. (2008)
USA
RCT
PEDro=7
N=12

Population: Moderate/ Severe TBI; Mean Age=35.75yr; Gender: Male=8, Female=4; Median Time Post Injury=3.3yr.
Treatment: In a crossover design, participants were randomly assigned to receive bromocriptine (1.25mg 2×/d titrated to 5mg 2×/d over a 1wk), followed by placebo or the reverse order. Each lasted 4wk with a 1wk washout period.
Outcome Measure: Sustained Arousal and Attention Task 50/50, Sustained Arousal and Attention Task 20/80, Speed/Accuracy Tradeoff Task, Distraction Task, Choice RT Task, Dual Task, Sustained Attention to Response Task, Inattentive Behaviour Task, Classroom Attentiveness, Attention Ratings.

  1. Though some improvements were observed in certain subtests of attentional tasks (e.g. speed decline, decline in responding, test of everyday attention), they were not significant.
  2. Overall results suggest bromocriptine had little effect on attention.

McDowell et al. (1998)
USA
RCT
PEDro=4
N=24

Population: TBI; Median Age=32.5yr; Gender: Male=20, Female=4; GCS Range=3-8; Time Post injury Range=27d-300mo.
Treatment: In a crossover design, participants were randomly assigned to receive 2.5mg bromocriptine (2.5mg) then placebo, or receive treatment in the reverse order.
Outcome Measure: Dual-task paradigm (counting and digit span), Stroop Test, spatial delayed-response task, Wisconsin Card Sorting Test (WCST), reading span test, Trail Making Test (TMT), controlled oral word association test (COWAT), and control tasks.

  1. Following bromocriptine treatment there were significant improvements on the dual-task counting (p=0.028), dual-task digit span (p=0.016), TMT (p=0.013), Stroop Test (p=0.05), COWAT (p=0.02), and WCST (p=0.041).
  2. Bromocriptine had no significant effects on working memory (e.g. spatial delayed-response task and reading span test; p=0.978), or on control tasks (p=0.095).

Powell et al. (1996)
UK
Case Series
N=11

Population: TBI=8, SAH=3; Mean Age=36yr; Gender: Male=6, Female=5; Time Post Injury Range=2mo-5yr.
Treatment: Patients received bromocriptine (a maximum dose of 5-10mg/d). Patient assessments included two baseline evaluations (BL1 and BL2), evaluation when stabilized at maximum bromocriptine dose (MAXBROMO), and two post withdrawal evaluations (POST1 and POST2).
Outcome Measure: Percentage participation index (PPI), spontaneity, motivation, card arranging reward responsivity objective test (CARROT), digit span, Buschke selective reminding test (BSRT), verbal fluency, and hospital anxiety and depression scale.

  1. Reported PPI (p<0.0001), motivation, and spontaneity (both p<0.005) increased significantly from BL2 to MAXBROMO. Improvements were seen in CARROT as well (p<0.0001).
  2. Significant improvements were observed from BL2 to MAXBROMO on the digit span (p<0.001), BSRT (p<0.01), and verbal fluency (p<0.001). Scores on all three tests decreased (non-significant) from MAXBROMO to POST1, scores recovered to near MAXBROMO levels by POST2.
  3. Bromocriptine was not associated with improvements in mood state.