“How-to” for RSA and Mean SC Data

Opening data file, which analysis software to use, and which buttons to click to analyze:

1. Plug the silver mindware USB drive into Henry (USB can be found in the drawer in the mindware CD case which also has a black USB in it- there are two cases)

2. Pull up HRV analysis on Henry (red symbol) a. For Mean GSC, pull up “EDA Analysis” (green symbol). All other

instructions are the same. 3. Open participant file # (i.e., 1000). 4. Use the dropdown to match up ECG to ECG, Zo-Zo, dz-dz then GSC to

EDA 5. In the events and mode tab, under filter events change to “keyboard”; on

the event identifier tab, change to “name” a. On top bar – “MODE” type should be set to ‘EVENT’ to allow

segment analysis of events that were keyboard inputted 6. R peak tab—on the baseline filter, make sure it is on (green) 7. Question will pop up: “Is ECG Inverted?” NO – it is not. 8. Click on ‘write’ at the top (white box) to get the excel sheet 9. Change event mode to “event to event + time”- change event to use to

“all” a. There should be 7 total events for a full data file. b. The time segments should be at 120 seconds (2 minutes).

10. Click on analyze to analyze the event segments. a. Analysis output should open in a single excel file.

11. To view a specific segment or see all segments, double click on segment number on the top left.

Cleaning data for artifacts: Refs: Berntston et al., 1998; Berntson et al., 1990; Thought Technology, Feb 2010, Basics of Heart Rate Variability: Applied to psychophysiology.

What is the order of events needed to RSA readings that we can interpret?

(Task Force, 1996, Circulation)

Then, what are artifacts, and what do they do? Artifacts cause spurious RSA readings, so we clean the data (called ‘normalizing’ the data in the field).

Note: IBI: Inter-beat interval. A few of the types that we see in our data:

RSA Data Cleaning When you open a data file in the HRV Analysis software, and click analyze, the software will automatically detect artifacts. The artifacts in the heart rate data will be indicated by the yellow markers. Blue markers are indicating the peaks of each beat (Rs in the QRS wave) that are not artifacts.

1. Once you click analyze, you will be able to see all peaks and artifacts in a given segment.

2. Each time segment will be nested within an event segment. 3. Even segments are noted by a neon green line, usually located at the end

of a time segment. a. If you hover your cursor over the green line, it will show which

keyboard event it is.

b. To edit a specific segment, select the segment you would like to edit, and then click “EDIT R”

4. If an artifact is noted, clean the artifact. The how-to is shown in the video called “Cleaning RSA” (the video is also located in YDL Contacts and Scheduling folder):

a. Basic steps: i. Identify where an artifact is.

1. Double check with participant hard copy notes and video file to make sure that the artifact is related to random error (i.e., a cough, researcher interruption, shifts in seat, bad readings, etc.). \

2. If the artifact is unrelated, keep artifact. ii. Place the two x-cursors at the two beats prior to and after

the artifact beat. iii. Delete the artifact. iv. Insert the midbeat, using the blue midbeat button. v. The goal of “normalizing” the data is to maintain the IBI

across a time segment of RSA analysis so as to not produce spurious results.

vi. The new appropriate midbeat, which is no longer an artifact, may not be placed at the peak of the beat, or even on the QRS line itself. The new midbeat is placed just to maintain the IBI through the event segment because HRV analysis requires that the time distribution of IBI values be maintained.

5. If a time segment within an event segment is overloaded with artifacts, or has a segment which needs to be cut due to random error (i.e., see above), exclude that time segment in later data consolidation. MAKE A NOTE OF IT ON PARTICIPANT DATA CLEANING NOTES HARD COPY PAGE.

6. If you wish to stop editing a file and return to it later, follow these steps:

a. Open HRV and load the unedited data file for the participant. b. Under “additional settings” tab (far right), check the box for “Use

Edited Data.” c. Make sure the program correctly selected the edited data file that

corresponds to the raw data file (e.g., 1040_0.edh goes with 1040_0).

d. Continue editing where you left off. EDA Data Cleaning EDA cleaning is less complicated. It is convention to cut out erroneous segments from a physiological recording and only process the error-free data from a given event segment. However, erroneous data should only be cut IF the physiological data is erroneous due to technical issues or problems with participant compliance (i.e., participant is moving too much, participant removes hand electrodes, or other non-random reasons why we need to exclude a specific time segment of skin conductance readings). The steps to opening a data file and “prepping” a data file for cleaning is identical to the initial steps for HRV/RSA analysis (except for the “inverted” step). Some definitional considerations: SCL = Skin conductance level SCR = Skin conductance response SCL-R = Skin conductance level responses = changes in the level of skin conductance between event segments. NSCR = Non-specific skin conductance response (i.e., a skin conductance response to an unidentifiable event, or an event that is unrelated to the event of interest, such as a stress task). E-SCR = Event-related skin conductance response (i.e., a skin conductance response to a specific event we are currently assessing)

A note: in the HRV Pilot study, because we use keyboard specific events that are not specifically linked to BioLab, we will not see any E-SCRs noted by the EDA analysis software.

Tonic EDA = Tonic electrodermal activity = This component of skin conductance refers to the overall levels and changes in SCL which more generally represent autonomic arousal reflected in SCL. It is slower to react to change (by slower, minutes relative to seconds).

Phasic SCRs = Phasic skin conductance responses = these responses are more acute in that they reflect specific responses to events; this component of skin conductance reflects the quicker changing aspects of SC. For example, with a timed stress event, identifying specific E-SCRs are essentially, whereas in events that are less time stringent and cover several minutes, SCL-reactions are more salient.

Note: in the HRV Pilot study, we are examining SCL-Rs, which examine change scores of SCL, rather than SCRs. This is a response assessment, where the assessment is based on skin conductance levels rather than on skin conductance responses. To obtain these assessments, we use averages of the “MEAN SC” which is just general mean skin conductance, which takes into consideration both tonic and phasic components of skin conductance.

In the EDA Analysis screen, there are several things to notice:

1) Each skin conductance response (non-specific or otherwise) will be denoted with a circle, square, and an x notation of the same color.

2) There may be time segments wherein which no skin conductance responses are noted. This is not erroneous – rather it is reflective of the fact that there were no specific skin conductance responses (i.e., no significant peaks/troughs in skin conductance levels) during that time period. It is quite normal.

3) The respiration rates are based on the Z0 measurements from the heart rate data. Large shifts in this graph area reflect a deep sigh, talking, laughing, etc.

When reviewing the skin conductance data:

1) Make sure to review the participant record notes beforehand. If there are specific notes regarding participant non-compliance, or technical issues, locate and exclude those time segments.

2) Review the data with the video file. a. If there are technical issues/participant non-compliance not noted in

participant records: i. Make new notes in participant records sheet of these errors. ii. Exclude the time segment containing the issues.

3) Skin conductance level readings will not show any potential artifacts. However, if in the participant record notes, a researcher notes that there were any issues at all with the skin conductance electrodes, that time segment must be excluded from later averages, analyses, etc.

The procedure for averaging and obtaining change scores from baseline to stress tasks are identical to HRV. You must use the residualized change scores using the syntax in the corresponding SPSS syntax file.