Vibrotactile piezoelectric stimulation system with precise and versatile timing control for somatosensory research.

BACKGROUND: Tactile stimulations systems are useful for studying the somatosensory system in children because they are innocuous and safe. Stimulators based on piezoelectric actuator are useful, but there is still a need for such systems capable of providing accurate and versatile control of timing and pattern of activation.

NEW METHOD: We have implemented a vibrotactile stimulating system useful for behavioral and electroencephalography (EEG) and magnetoencephalography (MEG) research. Our design goal was to create a system capable of providing up to five independently controlled mechanical stimulations with precise timing. We developed a Graphic User Interface (GUI) in LabVIEW, which controls a commercially available piezoelectric braille stimulator using an Arduino based controller. We made a customized braille stimulator based on the Metec Braille device.

RESULTS: Our system can control up to five tactile stimulators with independent timing control and negligible errors. Although it can be directly used for behavioral and EEG research, the piezoelectric stimulators in our system generate stimulus artifacts that interfere with MEG recordings. A moving averaging subtraction algorithm we developed can remove the artifact. The stimulator can be used to measure somatic evoked magnetic fields from the somatosensory cortex of a child without the artifact.

COMPARISON TO EXISTING METHODS: Our system provides an accurate independent control of one or more piezoelectric actuators using a GUI-based easy-to-control programming approach based on recent advances in embedded systems and software. Versatility and precise stimulation timing distinguish our system compared to existing somatic stimulators.

CONCLUSIONS: Our system may be useful for somatic research.