title: Evaluation of an easy, standardized and clinically practical method (SurePrep) for the preparation of electrode-skin contact in neurophysiological recordings.
abstract: The aim of this study was to assess the practicality, reliability and safety of a recently introduced method of skin preparation for EEG recordings. We compared the traditional skin abrasion (SA) method to a method called SurePrep (SP), which creates tiny incisions through the upper epithelial layers. The study comprised three parts. In part 1, forearm recordings (n = 400; ten healthy volunteers) were conducted to examine acute and late (24 h) impedances, skin reactions, as well as the effects on electrode movement artefacts. In part 2, the effect of repeated (up to nine) SP sticks on impedances was examined on the forearm skin in two subjects (n = 99). In part 3, preparation speed and skin impedances were measured from preparation of a standard EEG cap in four subjects (n = 74). Immediately after preparation, skin impedances were a little lower (n.s.) after SA, but the variability in impedances was significantly less after SP (p < 0.01). After one day, there was no mean impedance difference but a greater proportion of SP sites were >10 kOmega. The frequency of immediate skin irritations (93.5%) was much higher after SA compared to 42.5% after SP, but there was no clinically significant difference observed after one day. The SP method exposed interstitial fluid in 5% of cases, while SA caused a wound-like lesion in 4.5% of the sites. No macroscopic blood was observed in any case (n = 400). Three sticks with the SP device produced clinically sufficient (<10 kOmega) impedances in 85% of the cases, and a total of five to six sticks secured a sufficient skin contact in all skin sites examined (n = 99). Preparation of skin contacts in the EEG cap was faster by SP compared to SA in all four study subjects. Our results demonstrate that skin contacts of sufficient quality can be reliably, easily and quickly prepared by the SP method. SP is a useful alternative for EEG recordings in general, although SA may provide the slightly better preserved skin contacts needed for long-term recordings. Notably, SP could facilitate emergency care units, peripheral hospitals and after-hours EEG acquisition by people without special EEG training.
authors.affiliation: Department of Clinical Neurophysiology, University Hospital of Helsinki, Helsinki, Finland.
authors.forename: Susanna
authors.initials: S
authors.lastname: Stjerna
authors.forename: Päivi
authors.initials: P
authors.lastname: Alatalo
authors.forename: Jarmo
authors.initials: J
authors.lastname: Mäki
authors.forename: Sampsa
authors.initials: S
authors.lastname: Vanhatalo
mesh_terms: D000328:Adult; D016477:Artifacts; D017097:Electric Impedance; D004566:Electrodes; D004569:Electroencephalography / Q000295:instrumentation* / Q000592:standards*; D055724:Electrophysiological Phenomena; D005542:Forearm; D006801:Humans; D009482:Neurophysiology / Q000295:instrumentation* / Q000379:methods*; D012015:Reference Standards; D012879:Skin Physiological Phenomena; D013997:Time Factors; D055815:Young Adult