Abstract: A sleep assessment system includes a housing, processing circuitry, and a sensor assembly with a plurality of sensors configured to capture measurements that include indications of both brain and eye activity through the forehead of a subject. The processing circuitry is configured to receive sensor signals based on the measurements made by the plurality of sensors, process the sensor signals to generate sleep data, apply a sleep state convolutional neural network to the sleep data to determine a current sleep state of a subject, identify, based on the sleep data and the current sleep state, a sleep state-based data feature, and output a stimulus to the subject based on sleep state-based data feature. The housing is configured to be secured to the forehead of the subject, and the sensor assembly and processing circuitry are disposed on or within the housing.