Abstract:
Methods, systems, and devices are disclosed for monitoring electrical signals of the brain. In one aspect, a system for monitoring electrical brain activity associated with visual field of a user includes a sensor unit to acquire electroencephalogram (EEG) signals including a plurality of EEG sensors attached to a casing attachable to the head of a user, a visual display unit attachable to the head of the user over the user's eyes to present visual stimuli, in which the visual stimuli is configured to evoke multifocal steady-state visual- evoked potentials (mfSSVEP) in the EEG signals exhibited by the user acquired by the sensor unit, and a data processing unit in communication with the sensor unit and the visual display unit to analyze the acquired EEG signals and produce an assessment of the user's visual field, in which the assessment indicates if there is a presence of visual field defects in the user's visual field.
Abstract:
A system for assessing a mental health disorder in a human subject, the system comprising: a display configured to display a series of natural test images to the subject; an input by which the subject can input a response, following the display of each test image, as to whether or not the test image satisfies a predetermined categorisation criterion; a control processor configured to control the display of the test images by the display, to measure the duration of time from when each test image is initially displayed to when the corresponding response is input by the subject, and to generate a set of response data including the response times in respect of each of the test images; and a data processor configured to process the set of response data and to compare the processed response data with reference data to assess whether or not the subject has, or is likely to develop, the mental health disorder.
Abstract:
According to an aspect of the present invention, there is provided a measurement apparatus for measuring a property of an eye of a subject, comprising: a target arranged to be viewed by the subject, the target comprising a first light and a second light arranged to undergo a modulation in anti-phase, the modulation decreasing from an initial modulation frequency at which an initial flicker of the first light and second light is not perceivable by the subject; and an indication device allowing the subject to indicate when a flicker is perceived, the modulation frequency at which the subject indicates that the flicker is perceived being defined as a threshold modulation frequency.
Abstract:
The invention concerns an apparatus for automatically detecting the initial stage of a retinal or optical nerve disorder in a person's eye, in particular glaucoma, wherein eye flickering is measured at different frequencies of a modulated light source, by determining a deLange curve relative to that eye for said frequencies. The measuring apparatus (10) comprises a housing (11), provided with a triggering button (12) and a pushbutton (13) enabling the person whose eye is being examined to indicate when a white light source (22) has stopped blinking. Said source, automatically frequency- and modulation-controlled by a microprocessor, is housed in an eye cup (16) connected to the apparatus (10) by a connection (17). Light-emitting diodes (14) emitting different colours, indicate the result of the examination provided by a computing unit incorporated in the microprocessor. A communication port (15) enables the apparatus to be connected to peripheral units.
Abstract:
A method of measuring a flicker sensitivity distribution with high accuracy capable of keeping easily and reliably a fixation state of a subject without fatiguing the subject, comprising the step of flickering step-wise a target on a display screen (3) of a display (1) while changing luminance so that mean luminance of luminance when the target constituting one flickering of the target is bright and luminance when the target is dark is equal to luminance of the display screen (3) as the background of the target, and the step of determining a flicker sensitivity from luminance when the target constituting one flickering of the target is bright when flickering of the target is sensed and from luminance when the target is dark.
Abstract:
A device is disclosed which comprises a display adapted to display a sequence of rapidly alternating images, and a keypad electrically coupled to the display, for entering a perceived sequence by a user. The device is configured to compare a perceived sequence input by the user to the displayed sequence, and to measure the speed of visual perception of the user. Also disclosed are methods of visually, non-invasively assessing an individual's speed of visual perception (visual window of integration), or detecting any changes that have occurred in the individual's speed of visual perception.
Abstract:
A method of evaluating the response of a subject to visual features of a visual display, the method including the steps of: (a) presenting a visual display having particular visual features to the subject during a first period; (b) determining brain activity of the subject during the first period; (c) presenting reference display material to a subject during a second period; (d) determining reference brain activity of the subject during the second period; (e) tracking the gaze position of at least one of the eyes of the subject on the visual display during the first period; and (f) evaluating the response of the subject to particular visual features of the visual display by determining differences in brain activity determined between steps (b) and (d) when the gaze of the subject is directed at the particular features.
Abstract:
Method for detecting color vision deficiencies of a subject by determining his or her spectral sensitivity curve, wherein the spectral sensitivity curve is determined by critical fusion frequency spectral scanning at predetermined discrete narrow bands of wavelengths, preferably being blue, green, orange and red. The compensation of the color vision deficiency occurs by using a compensation color determined on the basis of differences between a standard sensitivity curve and the measured one. In each wavelength where such differences are experienced, the intensity of the light source generating that wavelength is increased or decreased in accordance with the extent and sign of the difference, and the compensation color is obtained by illuminating all light sources. The apparatus comprises a lighting unit (14) composed of light emitting diodes (B, G, O, R); a hollow tube (17) receiving the lighting unit (14) at one end region; an ocular lens (15) arranged at the frontal other end of the tube; a diapositive slide arranged across the tube which has a transparent pattern allowing passage of light towards places of the retina of the subject, where vision is provided purely by cones; a current generator circuit (40) including respective controlled current generators associated with the diodes (B, G, O, R), a pulse generator coupled to control inputs of the current generators for controlling pulsation of current flowing through the diodes; and a potientiometer adjustable by the subject under test for adjusting the repetition frequency of the pulse generator.