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AN INK-WRITING ELECTRO-ENCEPHALOGRAPH

1935; American Medical Association; Volume: 34; Issue: 6 Linguagem: Inglês

10.1001/archneurpsyc.1935.02250240161012

2330-9628

E. L. Garceau,

EEG and Brain-Computer Interfaces

The electrical potentials generated in the cerebral cortex may ultimately have considerable clinical as well as physiologic significance. Preliminary observations on these phenomena were carried out with a string galvanometer and a direct current amplifier 1 and with a cathode ray oscillograph and a capacity-coupled amplifier, 2 but it was soon evident that the most significant electrical waves had frequencies below 30 cycles per second and might therefore be successfully recorded by means of an ink-writing oscillograph. The advantages of obtaining an immediate permanent record on a paper tape at a cost of 1 cent per hundred feet are obvious. The problem was to obtain an ink-writing oscillograph with as high a frequency range as possible and to construct an amplifier to deliver to it sufficient current for its operation. Ink-writing oscillographs for this purpose have already been developed by Toennies 3 and by Adrian and Matthews, 4 but we