Saccadometry – new possibility for monitoring brain functional status

Abstract

Authors present an overview of hierarchical control of saccades, explaining why the saccadic refixation response is a cortically mediated activity. The time structure of saccadix refixation is discussed focusing on the long latency of response, which cannot be justified by physiological transmission delays. Cortical saccades procrastination is described based on the Professor Carpenter LATER Model. It is followed by the discussion of bioengineering aspects of saccadometry covering the selection of appropriate measurement technology and the expert system based eye movement signal analysis, aimed on extracting physiologically valid information about the brain functional status. Several examples are presented of the potential applicatio ns of saccadometry, including monitoring of severity and recovery from brain concussion, head exposure to high accelerations happening in contact sports, monitoring adaptation to high altitude and controlling mountain sickness, monitoring the neurodegenerative processes taking place in Huntington and Alzheimer diseases, as well as the possibility to optimize the placement of electrodes for deep brain stimulation. The concluding remark is: that the high sensitivity but low specificity of saccadic disturbances, usually considered as being disadvantageous for differential neurological diagnosis, should be seen as saccades main advantage, allowing to detect broad spectrum of brain dysfunctions at their earliest stage of development.