The alpha rhythm in electroencephalograph has been associated with the mental state of the brain. The aim of the present study was to analyze the complexity of the alpha activity in depression patients by Renyi entropy (RE) under two conditions, i.e., resting with eyes closed followed by a simple mental arithmetic. The EEGs were recorded in 20 depression patients and 20 age-matched control subjects. Results showed that the alpha activity of depression patients is more complex during resting and is more regular during the mental arithmetic than that of the controls. RE analysis can well characterize the alpha activity in depression patients and could be a valuable tool to study cognitive process and also a potential effective approach for the diagnosis of depression.
Adult ; Alpha Rhythm ; Depression ; physiopathology ; Electroencephalography ; Entropy ; Female ; Humans ; Male ; Signal Processing, Computer-Assisted

Retinal model is an essential part in the retinal prosthesis. Based on the retinal physiology and the experimental data, the model is able to simulate the information processing in the retina, and can be used to investigate the relation between the input image and the neuron firing. We can categorize the models into circuit realization and algorithm realization. This article is a state-of-art review of different types of retinal models.
Algorithms ; Humans ; Models, Biological ; Models, Neurological ; Neural Networks (Computer) ; Prostheses and Implants ; Retina ; anatomy & histology ; physiology

Cortical visual prosthesis, optic nerve visual prosthesis and vision substitution devices are alternative ways for repairing the visual impairment in case of optic nerve injury, retina lose or blindness without fully developed central visual system. This article is a state-of-art review of the principles, technical details and the limitations of different types of prostheses beyond the retinal prosthesis.
Animals ; Artificial Intelligence ; Electric Stimulation Therapy ; instrumentation ; methods ; Humans ; Optic Nerve ; physiopathology ; Prosthesis Design ; Prosthesis Implantation ; methods ; trends ; Retinal Ganglion Cells ; physiology ; Vision Disorders ; rehabilitation ; Visual Cortex ; physiopathology ; Visual Pathways ; physiopathology

Research on how to totally or partially restore the vision has attracted more attention in the fields of neural engineering and tissue engineering. Neural interface and visual prosthesis offer alternative ways for partially repairing the visual impairment. The most widely used visual prosthetics are based on retinal stimulation. This article is a state-of-art review of the principles, technical details and the limitations of retinal prosthesis.
Blindness ; therapy ; Electric Stimulation ; Electrodes, Implanted ; Humans ; Prosthesis Design ; methods ; trends ; Retina ; physiology ; Visual Perception ; physiology

Visually impaired people face many inconveniences because of the loss of vision. Therefore, scientists are trying to design various guidance systems for improving the lives of the blind. Based on sensory substitution, auditory guidance has become an interesting topic in the field of biomedical engineering. In this paper, we made a state-of-technique review of the auditory guidance system. Although there have been many technical challenges, the auditory guidance system would be a useful alternative for the visually impaired people.
Acoustics ; Auditory Perception ; Biomedical Engineering ; Equipment Design ; Humans ; Sensory Aids ; Software ; Sound Localization ; Visual Perception ; Visually Impaired Persons ; rehabilitation