Assessment technique for acne treatments based on statistical parameters of skin thermal images

Proc. Natl. Acad. Sci. U.S.A.

et al. 2015

325

283

Recent advances in electrodes for noninvasive recording of electroencephalograms expand opportunities collecting such data for diagnosis of neurological disorders and brain-computer interfaces. Existing technologies, however, cannot be used effectively in continuous, uninterrupted modes for more than a few days due to irritation and irreversible degradation in the electrical and mechanical properties of the skin interface. Here we introduce a soft, foldable collection of electrodes in open, fractal mesh geometries that can mount directly and chronically on the complex surface topology of the auricle and the mastoid, to provide highfidelity and long-term capture of electroencephalograms in ways that avoid any significant thermal, electrical, or mechanical loading of the skin. Experimental and computational studies establish the fundamental aspects of the bending and stretching mechanics that enable this type of intimate integration on the highly irregular and textured surfaces of the auricle. Cell level tests and thermal imaging studies establish the biocompatibility and wearability of such systems, with examples of high-quality measurements over periods of 2 wk with devices that remain mounted throughout daily activities including vigorous exercise, swimming, sleeping, and bathing. Demonstrations include a text speller with a steadystate visually evoked potential-based brain-computer interface and elicitation of an event-related potential (P300 wave).or more than 80 y, electroencephalography (EEG) has provided an effective noninvasive means to study human brain activity (1). EEG is instrumental in a wide range of clinical and research applications, from diagnosing epilepsy (2) to improving our understanding of language comprehension (3) and the development of brain-computer interfaces (BCI) (4). Conventional EEG recording systems, particularly the physical interface between the sensor (commonly known as an electrode) and the head, have limitations that constrain the more widespread use of EEG monitoring. Electrodes typically consist of rigid metal disks mechanically secured to the head with a mesh cap and chin strap, where electrolyte gels (5) enable efficient electrical coupling by reducing the impedance at the skin interface. This arrangement causes skin irritation (erythema) and leads to electrical degradation for periods of use that extend more than a few hours, typically caused by drying of the electrolyte gel (6). Recent technologies replace the gel (7, 8) with needles (8, 9), contact probes (10, 11), capacitive disks (12, 13), conductive composites (14, 15), or nanowires (16). Such dry electrodes have some promise, but they require multistep preparations, obtrusive wiring interfaces, and/or cumbersome mechanical fixtures. These shortcomings limit the potential for long-term use in diagnosis of neurological disabilities (17, 18) or in persistent BCI (17,19). For example, although microneedle electrodes can record EEG signals for a few hours (20), the interface does not offer the robustness, comfort, or eas...

Section: Resultsmentioning

confidence: 99%

Soft, curved electrode systems capable of integration on the auricle as a persistent brain–computer interface

Norton

Proc. Natl. Acad. Sci. U.S.A.

et al. 2015

325

283

Computer Methods and Programs in Biomedicine

“…IR is able to detect skin temperature differences as low as 0.1 • C [18]. These properties were applied in several medical cases as control of postsurgical infection [19], total knee replacement [20] and dermatological treatments [21,22].…”

Section: Discussionmentioning

confidence: 99%

Tuberculine reaction measured by infrared thermography

Fiz

Lozano

Monte

et al. 2015

Setting: The infection with Mycobacterium tuberculosis gives a delayed immune response, measured by the tuberculine skin test. We present a new technique for evaluation based on automatic detection and measurement of skin infrared emission. Design: 21 subjects (57.0±17.8 yr), (7/14, M/F) with suspected tuberculosis contact were examined with an IR thermal camera, 48 hours after skin injection. Results: In 15 subjects, IR analysis was positive for tuberculine test. Mean temperature of injection area was higher, around 1 ºC, for the positive group (36.0± 0.3 ºC positive group; 35.2±1.7 ºC negative group, p<0.001, Non parametric U Mann-Whitney Test). Conclusion: IR may represent an improved estimation of tuberculosis infection, given that it does not depend on reader variability and measures the increase of heat irradiation produced by the allergic tuberculine response. "NOTICE: this is the author's version of a work that was accepted for publication in . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Computer Methods and Programs in Biomedicine, vol.122, issue 2, (November 2015 Conclusion: IR may represent an improved estimation of tuberculosis infection,given that it does not depend on reader variability and measures the increase of heat irradiation produced by the allergic tuberculine response. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

“…The assessment of qualitative biocompatibility of the device utilizes a digital contact microscope to visually inspect the skin surface ( Figure 4C), which investigates the change of the skin color and texture over multiple cycles of use on patients. An infrared (IR) thermography can make a quantitative assessment of the skin conditions for about two weeks ( Figure 4D) since the side effects such as erythema causes temperature elevation 22 . The examined devices are laminated near the wound tissues and the contralateral location (as a reference).…”

Section: Representative Resultsmentioning

confidence: 99%

Fabrication and Characterization of a Conformal Skin-like Electronic System for Quantitative, Cutaneous Wound Management

Kwon

et al. 2015

JoVE

Recent advances in the development of electronic technologies and biomedical devices offer opportunities for non-invasive, quantitative assessment of cutaneous wound healing on the skin. Existing methods, however, still rely on visual inspections through various microscopic tools and devices that normally include high-cost, sophisticated systems and require well trained personnel for operation and data analysis. Here, we describe methods and protocols to fabricate a conformal, skin-like electronics system that enables conformal lamination to the skin surface near the wound tissues, which provides recording of high fidelity electrical signals such as skin temperature and thermal conductivity. The methods of device fabrication provide details of step-by-step preparation of the microelectronic system that is completely enclosed with elastomeric silicone materials to offer electrical isolation. The experimental study presents multifunctional, biocompatible, waterproof, reusable, and flexible/stretchable characteristics of the device for clinical applications. Protocols of clinical testing provide an overview and sequential process of cleaning, testing setup, system operation, and data acquisition with the skin-like electronics, gently mounted on hypersensitive, cutaneous wound and contralateral tissues on patients. Video LinkThe video component of this article can be found at