Table 1.
Changes in normalized cerebral glucose metabolism (mean, standard deviation) in subjects randomized to receive either pramipexole or placebo and effect sizes of pramipexole in regions-of-interest defined a priori
| Region of interest | Effect size (Pram/placebo) | Pramipexole |
Placebo |
||
|---|---|---|---|---|---|
| Pre | Post | Pre | Post | ||
| Orbitofrontal cortex | |||||
| Lefta | −1.22 | 1.14 (0.036) | 1.10 (0.058)c | 1.15 (0.031) | 1.15 (0.039) |
| Rightb | −1.04 | 1.12 (0.042) | 1.08 (0.049)c | 1.13 (0.037) | 1.12 (0.033) |
| Ventrolateral PFC | |||||
| Leftb | −0.91 | 1.14 (0.035) | 1.11 (0.042)d | 1.18 (0.040) | 1.19 (0.060) |
| Right | −0.39 | 1.13 (0.033) | 1.10(0.034) | 1.17 (0.053) | 1.16 (0.059) |
| Anteromedial PFC | |||||
| Left | −0.59 | 1.04 (0.035) | 1.01 (0.049) | 1.08 (0.077) | 1.09 (0.068) |
| Rightb | −1.10 | 1.09 (0.043) | 1.04 (0.046)c | 1.09 (0.072) | 1.09 (0.080) |
| Perigenual ACC | |||||
| Left | 0.78 | 1.11 (0.053) | 1.12 (0.062) | 1.15 (0.065) | 1.12 (0.051)d |
| Right | −0.07 | 1.10 (0.075) | 1.09 (0.058) | 1.10 (0.068) | 1.10 (0.068) |
| Dorsolateral PFC | |||||
| Left | −0.48 | 1.20 (0.036) | 1.18 (0.043) | 1.22 (0.047) | 1.21 (0.063) |
| Right | −0.28 | 1.19 (0.064) | 1.18 (0.053) | 1.20 (0.058) | 1.21 (0.060) |
| Amygdala | |||||
| Left | 0.27 | 0.94 (0.097) | 0.94 (0.075) | 0.86 (0.111) | 0.84 (0.107) |
| Right | 0.14 | 0.92 (0.062) | 0.93 (0.055) | 0.86 (0.063) | 0.86 (0.060) |
| Ventral striatum | |||||
| Left | −0.01 | 1.25 (0.100) | 1.27 (0.086) | 1.24 (0.099) | 1.26 (0.052) |
| Right | 0.37 | 1.31 (0.100) | 1.31 (0.139) | 1.26 (0.067) | 1.24 (0.087) |
| Anterior insula | |||||
| Left | −0.62 | 1.22 (0.051) | 1.18 (0.066) | 1.24 (0.058) | 1.24 (0.093) |
| Right | 0.49 | 1.20 (0.070) | 1.20 (0.062) | 1.25 (0.070) | 1.21 (0.110) |
ACC, Anterior cingulate cortex; PFC, prefrontal cortex.
Effect sizes (ES) of pramipexole relative to placebo in regions-of-interest calculated as the difference between mean pramipexole- and placebo-mediated metabolic change divided by the pooled standard deviation for the two means (Cohen, 1988).
ES: 0.2 = small, 0.5 = medium, 0.8 = large. A larger ES indicates greater percentage of non-overlap in the distribution of scores for the active treatment group with placebo group; e.g. an ES of 1.0 indicates a non-overlap of 55.4% of the two distributions.
Metabolic change during treatment differed between groups (p<0.05).
Metabolic change during treatment showed non-significant trend towards differing between groups at 0.05<p≤0.10.
Post-treatment metabolism changed from baseline at p<0.05.
Post-treatment metabolism showed non-significant trend towards differing from baseline at 0.05<p<0.10.