Cerebral Vasoregulation in Elderly with Stroke

Introduction

This database contains multimodal data from a large study investigating the effects of ischemic stroke on cerebral vasoregulation. The cross sectional study compared 60 subjects who suffered strokes, to 60 control subjects, collecting the following data for each patient across multiple days: transcranial doppler of cerebral arteries, 24-h blood pressure numerics, high resolution waveforms (ECG, blood pressure, CO2 and respiration) during various movement tasks, 24-h ECG, EMG, and accelerometer recordings, and gait pressure recordings during a walking test.

Background

Functional recovery after stroke depends upon integrity of cerebral vasoregulation. This project tested 3 hypotheses:

1. Older adults with ischemic stroke have impaired cerebral vasoregulation, rendering cerebral blood flow dependent on blood pressure.
2. Autonomic blood pressure control is impaired after stroke. Activities of daily living may induce hypotension, posing a risk of hypoperfusion.
3. The distribution of impaired vasoreactivity extends beyond the infarct region into surrounding gray and white matter, affecting other vascular territories.

We investigated cerebral vasoregulation using transcranial Doppler (TCD) ultrasound and arterial spin labeling MRI at 3 Tesla, to determine the impact of stroke on cerebral blood flow regulation, autonomic 24 blood pressure control, postural control and cognition during daily living activities in older adults with and without minor stroke.

Data Collection

The full-study-protocol.docx file contains a writeup of the full experimental protocol. The day1-day2-protocol.docx file describes the data collected from the patients during the two main experimental days at the clinic.

Multiple separate sensors were used to measure patient data. The disparate sensor information was combined and synchronized. Some files in this database contain overlapping signals. No information/support will be provided regarding this process.

Files

The open-format data files are in the data folder, which contains over 100GB of data files (not including the raw archived data), 98GB of which come from the 24h-electromyography subdirectory.

The subjects.csv file contains patient information.

The conversion folder contains an archive of the original semi-processed raw data, in proprietary and open forms including text, labview, and tff. It also contains the convert-final.ipynb Python notebook file containing the code used to convert the data to open format. The beat-to-beat blood pressure data collected using the Portapress device has not been converted into an open format. In addition, there is no MRI data from the experiments available in this database. No information/support will be provided regarding the data conversion process.

The day1-day2-protocol.docx file contains descriptions of the experiments and their relative times. The individual data files (text and wfdb) contain the starting times of the measurements. WFDB files can be read using one of the software packages.

The following folders within the data directory contain the following items (see also the day1-day2-protocol.docx file for more details):

• 24h-bp - From day 1. 24-hour beat-to-beat heart rate and BP monitoring using Dynapulse. BP was measured at 20 minute intervals during daytime and at 30 minute intervals at night. The files are in text csv format. There is a raw and verified version for each subject.
• sit-stand - From the first day 1 sit to stand test. Heart rate, blood and BFV in the middle cerebral artery measured by Doppler ultrasound during 5 min sitting and after 1 and 3 minutes of standing using Labview at 500 Hz. The files are in WFDB format.
• 24h-electromyography - From day 1. 24-hour ECG and EMG monitoring using the ME6000 device, sampled at 1000 Hz. The files are in WFDB format. In addition, the .marker WFDB annotation files contain locations of event markers.
• transcranial-doppler - From day 2. TCD measurements of BFV from three arteries, and other vital signs. The files are in WFDB format. In addition, the .marker WFDB annotation files contain locations of event markers.
• head-up-tilt - From day 2. Combined vitals from multiple instruments. ECG, ABP, both middle cerebral artery blood flow velocities from TCD, temperature, O2, and CO2. The files are in WFDB format.
• sit-stand-balance - From day 2. Multiparameter vitals collected from multiple instruments. Superset of signals in head-up-tilt along with force movement data. The files are in WFDB format.
• walking - From day 2. The subject walked in a circular hallway for 12 minutes. Level of exertion, walking distance and speed were measured. The files are in WFDB and text csv format.

In addition, the publications folder contains many articles published from this database

Contributors

NIH-National Institute of Neurological Disorders and Stroke R01-NS045745, NIH-National Institute of Neurological Disorders and Stroke grant to Vera Novak.

Contact

For further information, please contact:

Vera Novak, MD, PhD
Associate Professor of Neurology
Dept. of Neurology, Stroke Division
Director Syncope and Falls in the Elderly Laboratory
vnovak@bidmc.harvard.edu