Table 3.
Correlations between cerebellar GABA, Glx levels, excitation/inhibition balance and dopamine replacement therapy (daily levodopa equivalents), response inhibition measures in the studied samples and results from the test of difference between correlation.
|
Mean GABA
r to z (p level) |
GABA left
r to z (p level) |
GABA right
r to z (p level) |
|||||||
| HC = 20 | PD = 20 | Z-test z (p level) |
HC = 20 | PD = 20 | Z-test z (p level) |
HC=20 | PD = 20 | Z-test z (p level) |
|
| levodopa eq. (mg/day) | - | 0.007 (.98) | - | - | 0.06 (0.80) | - | - | −0.05 (0.85) | - |
| M-WCST-sf P | 0.05 (0.82) | 0.31 (0.19) | −0.79(ns) | 0.11 (0.64) | 0.11 (0.63) | 0 (ns) | −0.03 (0.91) | 0.35 (0.12) | −1.15(ns) |
| SWCT-sv IE-T | −0.47 (0.03) | 0.39 (0.09) | −2.69 (0.007) * | −0.25 (0.29) | 0.13 (0.59) | −1.13 (ns) | −0.55 (0.01) | 0.45 (0.04) | −3.22 (0.001) * |
| SWCT-sv IE-E | −0.42(0.06) | 0.48 (0.03) | −2.83 (0.005) * | −0.30 (0.20) | 0.53 (0.01) | −2.62 (0.009) * | −0.40 (0.08) | 0.21 (0.36) | −1.86 (ns) |
|
Mean Glx
r to z (p level) |
Glx left
r to z (p level)) |
Glx right
r to z (p level)) |
|||||||
| HC = 20 | PD = 20 | Z-test z (p level) |
HC = 20 | PD = 20 | Z-test z (p level) |
HC = 20 | PD = 20 | Z-test z (p level) |
|
| levodopa eq. (mg/day) | - | −0.50 (0.02) | - | - | −0.36 (0.11) | - | - | −0.43 (0.06) | - |
| M-WCST-sf P | 0.06 (0.80) | 0.31 (0.18) | −0.76 (ns) | −0.28 (0.24) | 0.21 (0.36) | −1.46 (ns) | 0.37 (0.10) | 0.28 (0.24) | 0.29 (ns) |
| SWCT-sv IE-T | 0.07 (0.78) | 0.09 (0.71) | −0.06 (ns) | −0.002 (0.1) | −0.01 (0.96) | 0.02 (ns) | 0.10 (0.67) | 0.14 (0.54) | −0.12 (ns) |
| SWCT-sv IE-E | −0.18 (0.44) | 0.30 (0.19) | −1.43 (ns) | −0.25 (0.28) | 0.06 (0.79) | −0.92 (ns) | −0.02 (0.94) | 0.40 (0.08) | −1.29 (ns) |
|
Mean E/I (Glx/GABA)
r to z (p level)) |
E/I (Glx/GABA) left
r to z (p level)) |
E/I (Glx/GABA) right
r to z (p level)) |
|||||||
| HC = 20 | PD = 20 | Z-test z (p level) |
HC = 20 | PD = 20 | Z-test z (p level) |
HC = 20 | PD = 20 | Z-test z (p level) |
|
| levodopa eq. (mg/day) | - | −0.29 (0.21) | - | - | −0.32 (0.17) | - | - | −0.21 (0.37) | - |
| M-WCST-sf P | −0.03 (0.89) | −0.12 (0.61) | 0.26 (ns) | −0.28 (0.23) | −0.06 (0.79) | −0.66 (ns) | 0.25 (0.29) | −0.13 (0.58) | 1.13 (ns) |
| SWCT-sv IE-T | 0.40 (0.07) | −0.28 (0.23) | 2.07 (0.03) | 0.13 (0.59) | −0.19 (0.42) | 0.94 (ns) | 0.51 (0.02) | −0.22 (0.35) | 2.29 (0.02) |
| SWCT-sv IE-E | 0.27 (0.25) | −0.22 (.36) | 1.46 (ns) | 0.06 (0.81) | −0.35 (0.13) | 1.24 (ns) | 0.37 (0.10) | −0.03 (0.90) | 1.22 (ns) |
Legend: HC, healthy controls; E/I excitation/inhibition; GABA, gamma-aminobutyric acid; Glx, Glutamate/Glutamine complex; M-WCST-sf P, Modified Wisconsin Card Sorting Test short form perseverative errors; ns, non-significant; PD, Parkinson disease patients; r to z, Fisher’s r to z transformation; SWCT-sv IE-E, Stroop Word-Color Test short form, error interference effect; SWCT-sv IE-T, Stroop Word-Color Test short form, time interference effect. *Significant after correction for multiple comparisons (i.e., p < 0.01 see text for reference). Bold values indicate statistical significance.