Cerebral hemodynamic monitoring of Parkinson’s disease patients with orthostatic intolerance during head-up tilt test

Abstract

Significance: Monitoring of cerebral perfusion rather than blood pressure changes during a head-up tilt test (HUTT) is proposed to understand the pathophysiological effect of orthostatic intolerance (OI), including orthostatic hypotension (OH), in Parkinson's disease (PD) patients. Aim: We aim to characterize and distinguish the cerebral perfusion response to a HUTT for healthy controls (HCs) and PD patients with OI symptoms. Approach: Thirty-nine PD patients with OI symptoms [10 PD patients with OH (PD-OH) and 29 PD patients with normal HUTT results (PD-NOR)], along with seven HCs participated. A 108-channel diffuse optical tomography (DOT) system was used to reconstruct prefrontal oxyhemoglobin (HbO), deoxyhemoglobin (Hb), and total hemoglobin (HbT) changes during dynamic tilt (from supine to 70-deg tilt) and static tilt (remained tilted at 70 deg). Results: HCs showed rapid recovery of cerebral perfusion in the early stages of static tilt. PD-OH patients showed decreasing HbO and HbT during dynamic tilt, continuing into the static tilt period. The rate of HbO change from dynamic tilt to static tilt is the distinguishing feature between HCs and PD-OH patients. Accordingly, PD-NOR patients were subgrouped based on positive-rate and negative-rate of HbO change. PD patients with a negative rate of HbO change were more likely to report severe OI symptoms in the COMPASS questionnaire. Conclusions: Our findings showcase the usability of DOT for sensitive detection and quantification of autonomic dysfunction in PD patients with OI symptoms, even those with normal HUTT results.

Frontal lobe hemodynamics detected by functional near-infrared spectroscopy during head-up tilt table tests in patients with electrical burns

“…The fNIRS response to the HUT was divided into five phases: baseline, dynamic tilt-up phase, static tilt phase, dynamic tilt-down phase, and post-tilt phase. The HUT protocol was performed in a similar method with reference to previous studies (Sundkvist and Lilja, 1983 ; Jahan et al, 1996 ; Kim et al, 2020b ). After a 20-min rest in the supine position, the baseline BP and HR were recorded (Task A).…”

Regional analysis of cerebral hemodynamic changes during the head-up tilt test in Parkinson’s disease patients with orthostatic intolerance

“…[15][16][17] In our recent DOT study, we found that the rate of oxyhemoglobin (HbO) changes from the dynamic to the static tilt phase may be a sensitive marker for differentiating healthy controls (HCs) from PD patients with OH (PD-OH). 18 Our previous study also suggested that DOT measurements provide information on cerebral reoxygenation that cannot be gleaned from conventional BP monitoring during HUTT, particularly in patients with PD who have normal HUTT results (PD-NOR). 18 The regional analysis of the brain in PD-OH patients showed that specific cerebral structures are involved in autonomic control.…”

“…18 Our previous study also suggested that DOT measurements provide information on cerebral reoxygenation that cannot be gleaned from conventional BP monitoring during HUTT, particularly in patients with PD who have normal HUTT results (PD-NOR). 18 The regional analysis of the brain in PD-OH patients showed that specific cerebral structures are involved in autonomic control. Pathological studies have shown that neurodegenerative processes associated with alpha-synuclein pathology along the central structures are responsible for autonomic control, which may have implications for the pathophysiological mechanism underlying OH in patients with PD.…”

“…However, previous studies did not focus on the autonomic dysfunction associated with PD, [23][24][25] or they did not compensate for regional hemodynamic changes across a wide area of the brain during dynamic tilting. 13,18 Pathological changes in the central autonomic network (CAN) also play a key role in PD-OH; thus, investigating the central regions associated with OH during dynamic and static tilts in patients with PD may further elucidate the pathophysiological mechanisms underlying autonomic dysfunction in PD patients.…”

“…Few studies have investigated the central regions that are associated with PD-OH; 21,22 therefore, we extended our previous DOT study to include a regional analysis of cerebral oxygenation across the frontal area during the dynamic and static tilt phases of HUTT in PD patients showing OI symptoms. 18 To our knowledge, no study has localized the areas of altered cerebral oxygenation during HUTT in patients with PD. We aimed to analyze the dynamic changes in oxygenation during tilting according to the neuroanatomical labels defined by the Automated Anatomical Labeling (AAL) system, which is a parcellation of the brain that has been widely used in neuroimaging research, including DOT studies, 26,27 to identify anatomical regions of interest.…”