Method for identification of pathological brain activity from scalp electroencephalogram

A system for detecting brain activity patterns, the system comprising a data processing system configured to:

• a) obtain electroencephalographic signals as a function of multiple channels and time;
• b) identify, for each channel, the zero-crossings of its corresponding electroencephalographic signal over a fixed threshold;
• c) generate a zero-crossing representation of the electroencephalographic signals with the identified zero-crossings;
• d) obtain at least one reference family of functions of time and channels from a zero-crossing statistical analysis of a zero-crossing representation of pre-recorded electroencephalographic signals, the functions of the at least one reference family of functions being real functions;
• e) for each segment of a plurality of segments of the generated zero-crossing representation, calculate a corresponding matching score by comparing said zero-crossing representation of the segment with at least one reference function from the at least one reference family of functions;
• f) monitor an evolution of the matching score over time based on a set of calculated matching scores for successive segments of the generated zero-crossing representation;
• wherein, for each segment, the corresponding matching score relative to a zero-crossing representation of a segment for one reference function T centered in t0 is defined by the formula:
• ST(t0)=Σk εKΣtεϕ(k,t0)Tk(t−t0),
• wherein ST(t0) is the matching score, the first sum runs over the set of channels k εK, and the second sum runs over a defined subset t εϕ(k, t0) of zero-crossings for each channel k of the segment surrounding t0;
• and
• g) determine a state of the brain based on the evolution of the matching score.

A non-transitory computer program product for detecting brain activity patterns, the computer program product comprising instructions which, when the instructions are executed by a computer, cause the computer to carry out a method comprising the steps of:

• a) obtaining electroencephalographic signals as a function of multiple channels and time;
• b) identifying, for each channel, the zero-crossings of its corresponding electroencephalographic signals over a fixed threshold;
• c) generating a zero-crossing representation of the electroencephalographic signals with the identified zero-crossings;
• d) obtaining at least one reference family of functions of time and channels from a zero-crossing statistical analysis of a zero-crossing representation of pre-recorded electroencephalographic signals, the functions of the at least one reference family of functions being real functions;
• e) for each segment of a plurality of segments of the generated zero-crossing representation, calculating a corresponding matching score by comparing said zero-crossing representation of the segment with at least one reference function from the at least one reference family of functions;
• f) monitoring an evolution of the matching score over time based on a set of matching scores for successive segments of the generated zero-crossing representation;
• wherein, for each segment, the corresponding matching score relative to a zero-crossing representation of a segment for one reference function T centered in t0 is defined by the formula:
• ST(t0)=Σk εKΣtεϕ(k,t0)Tk(t−t0),
• wherein ST(t0) is the matching score, the first sum runs over the set of channels k εK, and the second sum runs over a defined subset t εϕ(k, t0) of zero-crossings for each channel k of the segment surrounding t0;
• and
• g) determining a state of the brain based on the evolution of the matching score.

A non-transitory computer-readable storage medium comprising instructions which, when the instructions are executed by a computer, cause the computer to carry out a method comprising the steps of:

• a) obtaining electroencephalographic signals as a function of multiple channels and time;
• b) identifying, for each channel, the zero-crossings of its corresponding electroencephalographic signal over a fixed threshold;
• c) generating a zero-crossing representation of the electroencephalographic signals with the identified zero-crossings;
• d) obtaining at least one reference family of functions of time and channels from a zero-crossing statistical analysis of a zero-crossing representation of pre-recorded electroencephalographic signals, the functions of the at least one reference family of functions being real functions;
• e) for each segment of a plurality of segments of the generated zero-crossing representation, calculating a corresponding matching score by comparing said zero-crossing representation of the segment with at least one reference function from the at least one reference family of functions;
• f) monitoring an evolution of the matching score over time based on a set of matching scores for successive segments of the generated zero-crossing representation;
• wherein, for each segment, the corresponding matching score relative to a zero-crossing representation of a segment for one reference function T centered in t0 is defined by the formula:
• ST(t0)=Σk εKΣtεϕ(k,t0)Tk(t−t0),
• wherein ST(t0) is the matching score, the first sum runs over the set of channels k εK, and the second sum runs over a defined subset t εϕ(k, t0) of zero-crossings for each channel k of the segment surrounding t0;
• and
• g) determining a state of the brain based on the evolution of the matching score.