ELECTRODES AND ELECTRODE UNITS FOR GATHERING ELECTROENCEPHALOGRAPHIC DATA
Electrodes and electrode units for gathering electroencephalographic data are described herein. An example electrode unit includes a housing and an electrode coupled to and extending from the housing. The electrode includes a first shell, a second shell retractable relative to the first shell, a third shell retractable relative to the second shell, and an electrode pin retractable relative to the third shell. The first shell, the second shell, the third shell, and the electrode pin are configured in a telescoping arrangement and moveable between an expanded state and a compressed state. The electrode includes a spring to bias the second shell outward from the first shell, the third shell outward from the second shell, and the electrode pin outward from the third shell to contact skin of a subject.
1 . An electrode unit comprising:
a housing; and
an electrode coupled to and extending from the housing, the electrode including a first shell, a second shell retractable relative to the first shell, a third shell retractable relative to the second shell, and an electrode pin retractable relative to the third shell, the first shell, the second shell, the third shell, and the electrode pin configured in a telescoping arrangement and moveable between an expanded state and a compressed state, the electrode including a spring to bias the second shell outward from the first shell, the third shell outward from the second shell, and the electrode pin outward from the third shell to contact skin of a subject.
2 . The electrode unit of claim 1 , wherein the spring extends through the first shell, the second shell, and the third shell.
3 . The electrode unit of claim 2 , wherein the spring extends between a top end of the first shell and a top end of the electrode pin.
4 . The electrode unit of claim 3 , wherein the electrode pin has a tip, opposite the top end of the electrode pin, that is to contact the skin of the subject.
5 . The electrode unit of claim 3 , wherein the top end of the electrode pin is tapered.
6 . The electrode unit of claim 3 , wherein the spring is a first spring, the electrode further including a second spring, the second spring extending between the top end of the first shell and a top end of the third shell, the second spring to bias the third shell outward.
7 . The electrode unit of claim 6 , wherein the electrode further includes a third spring, the third spring extending between the top end of the first shell and a top end of the second shell, the third spring to bias the second shell outward.
8 . The electrode unit of claim 7 , wherein the first, second, and third springs are concentric.
9 . The electrode unit of claim 1 , wherein the third shell includes a stop that is engaged by the electrode pin in the compressed state, such that a portion of the electrode pin extends outward from an end of the third shell.
10 . The electrode unit of claim 1 , wherein the housing includes an opening defining a cavity, the first shell removably disposed in the cavity, the first shell having a flange, the flange being clamped between a connector and a ledge formed in the opening in the housing.
11 . The electrode unit of claim 1 , wherein a tip of the electrode pin has an end surface with a recess extending into the end surface such that the end surface forms a ring around the recess, the end surface being substantially flat.
12 . The electrode unit of claim 1 , wherein a tip of the electrode pin has a first end surface being perpendicular to a side surface of the electrode pin, the tip having a hump extending from the first end surface such that the first end surface surrounds the hump, the hump having a second end surface spaced apart from the first end surface.
13 . An electrode unit comprising:
a housing; and
an electrode extending from the housing, the electrode having:
a first end surface;
a side surface perpendicular to the end surface; and
a hump extending from the first end surface such that the first end surface surrounds the hump, the hump having a second end surface spaced apart from the first end surface.
14 . The electrode unit of claim 13 , wherein the hump extends from the first end surface about 0.4 millimeters.
15 . The electrode unit of claim 13 , wherein the second end surface is parallel to the first end surface.
16 . The electrode unit of claim 13 , wherein an edge between the second end surface and a side surface of the hump is rounded.
17 . An electrode unit comprising:
a housing; and
an electrode extending from the housing, the electrode having a tip with an end surface and a recess extending into the end surface such that the end surface forms a ring around the recess, the end surface being substantially flat.
18 . The electrode unit of claim 17 , wherein an outer edge between the end surface and a side surface of the electrode is rounded.
19 . The electrode unit of claim 18 , wherein an inner edge between the end surface and a side surface that defines the recess is rounded.