Apply a drop of gel to the electrode (but not so much as to spread and prevent it from sticking well); apply to pre-gelled disposable electrodes if they look dry or do not provide a strong signal.
Wait at least 5 minutes before starting the recording so that the gel can be absorbed into the skin; this will reduce the impedance.
Check the impedance level—use the “Electrode Check” built-in impedance checker on MP3X units, or add BIOPAC’s EL-CHECK to your recording protocol to measure the impedance between surface electrodes attached to a subject before you begin recording…then correct any noise issues before you begin to record great data!
EL-CHECK is suitable for measuring electrode contact impedance for all surface biopotential measurements, including those for ECG, EEG, EGG, EMG, EOG, Bioimpedance and Impedance Cardiography. The EL-CHECK permits simultaneous connection of up to three electrode leads, for quick impedance checking between any two electrodes.
As a rule of thumb, impedance levels below 10 kOhms are ideal, and the lower the better.
To prevent movement artifacts, use tape to attach the electrode leads to the skin. Unless recording fMRI/MRI, make a loop with the electrode lead cable under the tape to reduce the chance of dislodging the electrode due to a sudden pull.
Each amplifier has several gain settings. Use the highest gain setting possible which does not cause data to clip (data will clip when the signal is amplified so much that it goes beyond the -10 to +10 volt range of the system). High gain takes full advantage of the high resolution capability of the system and increases measurement sensitivity.
When calibrating a transducer, whenever possible use calibration values that encompass the range in which you will be recording. For example, if you are using a force transducer and anticipate working in the range 5 to 50 grams, use a 5 gram and a 50 gram weight for calibrating.
For airflow transducers, use flow rates that are similar to those you intend to record.
The STMTHERM is a thermal stimulator that can deliver both hot and cold temperature stimulation to a subject. The STMTHERM can be used to identify participant thermoreceptor response thresholds for a variety of applications. The STMTHERM consists of two parts, the Stimulator Control Unit (SCU) and the included Thermal Stimulation Transducer (TSD191 Thermode) to deliver temperature […]
Recent studies in Psychophysiology, EMG, ECG and PPG measurement utilizing BIOPAC software and hardware: Fight or Flight (Reflex Response Time) “Fight or flight” is a physiological response that occurs due to a perceived threat to survival. It can physiologically be observed through an increase in heart rate, respiratory rate, blood pressure, oxygen availability, and other mechanisms. In […]
HRV, EMG, and EEG studies using BIOPAC hardware and software include: DON’T STRESS Humans encounter various stressful situations everyday at work, home, and school. Such stress when experienced at high degrees and/or for a long duration of time could lead to cardiovascular diseases, cognitive dysfunctions, and psychological disorders. This study examined the validity of a novel physiological measurement […]