4 research outputs found
Problems in assessment of novel biopotential front-end with dry electrode:A brief review
Developers of novel or improved front-end circuits for biopotential recordings using dry electrodes face the challenge of validating their design. Dry electrodes allow more user-friendly and pervasive patient-monitoring, but proof is required that new devices can perform biopotential recording with a quality at least comparable to existing medical devices. Aside from electrical safety requirement recommended by standards and concise circuit requirement, there is not yet a complete validation procedure able to demonstrate improved or even equivalent performance of the new devices. This short review discusses the validation procedures presented in recent, landmark literature and offers interesting issues and hints for a more complete assessment of novel biopotential front-end
Wearable electroencephalography for long-term monitoring and diagnostic purposes
Truly Wearable EEG (WEEG) can be considered as the future of ambulatory EEG
units, which are the current standard for long-term EEG monitoring. Replacing
these short lifetime, bulky units with long-lasting, miniature and wearable devices
that can be easily worn by patients will result in more EEG data being collected for
extended monitoring periods. This thesis presents three new fabricated systems, in
the form of Application Specific Integrated Circuits (ASICs), to aid the diagnosis of
epilepsy and sleep disorders by detecting specific clinically important EEG events
on the sensor node, while discarding background activity. The power consumption
of the WEEG monitoring device incorporating these systems can be reduced since
the transmitter, which is the dominating element in terms of power consumption,
will only become active based on the output of these systems.
Candidate interictal activity is identified by the developed analog-based interictal
spike selection system-on-chip (SoC), using an approximation of the Continuous
Wavelet Transform (CWT), as a bandpass filter, and thresholding. The spike
selection SoC is fabricated in a 0.35 μm CMOS process and consumes 950 nW.
Experimental results reveal that the SoC is able to identify 87% of interictal spikes
correctly while only transmitting 45% of the data.
Sections of EEG data containing likely ictal activity are detected by an analog
seizure selection SoC using the low complexity line length feature. This SoC is
fabricated in a 0.18 μm CMOS technology and consumes 1.14 μW. Based on experimental
results, the fabricated SoC is able to correctly detect 83% of seizure
episodes while transmitting 52% of the overall EEG data.
A single-channel analog-based sleep spindle detection SoC is developed to aid
the diagnosis of sleep disorders by detecting sleep spindles, which are characteristic
events of sleep. The system identifies spindle events by monitoring abrupt changes
in the input EEG. An approximation of the median frequency calculation, incorporated
as part of the system, allows for non-spindle activity incorrectly identified
by the system as sleep spindles to be discarded. The sleep spindle detection SoC
is fabricated in a 0.18 μm CMOS technology, consuming only 515 nW. The SoC
achieves a sensitivity and specificity of 71.5% and 98% respectively.Open Acces
Innovaciones en sistemas e interfaces humano-máquina: aplicación a las tecnologÃas de rehabilitación
La presente Tesis Doctoral se ha desarrollado en el entorno de trabajo del Laboratorio de
Electrónica y BioingenierÃa de la Universidad de Valladolid, que enfoca su actividad en varias
lÃneas de investigación dedicadas a la asistencia de discapacitados mediante la aplicación de
TecnologÃas de Rehabilitación (TR). Concretamente, la labor investigadora del autor se ha
centrado en la implementación de diferentes interfaces persona-máquina, innovadoras y
adaptadas a la discapacidad, cuya finalidad es facilitar la interacción del usuario con su entorno.
Con objeto de aportar una funcionalidad práctica, el autor de la Tesis ha participado,
sustancialmente, en el desarrollo de diferentes dispositivos y sistemas que incorporasen sus
innovaciones técnicas. Estos trabajos están orientados a conseguir ayudas para mejorar la
autonomÃa personal, además de entrenadores de rehabilitación para personas con discapacidades
severas.Departamento de TeorÃa de la Señal y Comunicaciones e IngenierÃa Telemátic