Table 3.
CBFV step response parameters to changes in blood pressure, end-tidal CO2 and neural stimulation.
| Step response input | HC (n = 51) | PD (n = 34) | P-value | ||
|---|---|---|---|---|---|
| BP (ARI) | 7.5 ± 1.5 | 6.2 ± 2.3 | <0.01 | ||
| CO2 step (cm.s−1.mmHg−1) | 1.8 ± 1.5 | 0.93 ± 0.7 | <0.01 | ||
|
Dominant |
Non-dominant |
Onset |
Non-onset |
||
| Stimulus (a.u.) | 4.5 ± 2.3 | 3.5 ± 2.5 | 3.2 ± 2.0 | 3.4 ± 1.6 | *0.02 |
Note: ARI describes the temporal pattern of the CBFV step response to the BP input. For the CO2 and stimulus inputs, the CBFV step response is represented by the mean value of the plateau (Figure 4) from 30 to 40 s into the response. Values are means ± SD. Hemispheric data were averaged for ARI and the CO2 step response, but significant differences between hemispheres in HC led to the response to stimulation being analysed separately.
HC: healthy controls; PD: Parkinson’s disease patients; BP: blood pressure; ARI: autoregulation index.
P-values, unpaired t-test.
*p-value from the General Linear Model. Post-hoc Tukey testing identified the difference between HC (dominant) and PD (onset), p = 0.04.