Patent ID: 8244341

Claim:
A method for determining a mental condition of a subject by measuring bioelectromagnetic signals of the brain and calculating a spectral asymmetry index representing the mental condition, the method comprising: obtaining a recorded bioelectromagnetic signal from only one site on the subject's brain during a predetermining period of time; performing, on a processor, a power spectral calculation on said recorded bioelectromagnetic signal; defining a lower frequency band of said bioelectromagnetic signal, said lower frequency band having a second limiting frequency that is below a lower limiting frequency of an alpha band of said bioelectromagnetic signal of the brain, and a first limiting frequency chosen below said second limiting frequency, and calculating a first power of said bioelectromagnetic signal within said lower frequency band; defining a higher frequency band of said bioelectromagnetic signal, said higher frequency band having a third limiting frequency that is above a higher limiting frequency of an alpha band of said bioelectromagnetic signal of the brain, and a fourth limiting frequency chosen above said third limiting frequency, and calculating a second power of said bioelectromagnetic signal within said higher frequency band; calculating a spectral asymmetry index by subtracting the first power value from the second power value and dividing the result with the sum of the first power value and the second power value; and defining a positive determination of the mental condition when the spectral asymmetry index is in the first predetermined range and defining a negative determination of the mental condition when the spectral asymmetry index is in the second predetermined range.