 Comfortable, flexible head caps for the
ActiveTwo system
The
ActiveTwo head cap was developed in cooperation with Dr. Peter Praamstra at the
Behavioral Brain Sciences Center, University of Birmingham, United Kingdom.
The head cap consists of an elastic cap with plastic electrode holders.
The cap itself does not contain electrodes - only plastic electrode holders that
receive the pin-type active electrodes. The caps have ear-slits for easy
access to the ears. Head-caps are provided with an elastic / velcro chin
strap for fixing the cap in place, but body harnesses with criss-cross chest
straps are also available. The fabric template of the standard caps is
suitable for positioning electrodes at traditional 10/20 positions. |
Please note that the
ActiveTwo head-cap and associated
active electrodes are designed
only for use with the ActiveTwo system.
They cannot be used with other types of bioamplifiers.
 Electrode
holders
Electrode holders do just what their name says -- they hold the
pin-type active electrodes in place. These holders are designed to
be used with the elastic fabric material of the standard head caps we
offer, but they can also be used in other types of head caps or even
other types of garments for holding the pin-type electrodes on the body.
Each electrode holder consists of three parts: a flared base with gel
cavity, top tab with recessed circular insert for label and a rubber
X-ring that provides friction to hold the electrode in place. The
holders can be disassembled and relocated in the cap to change electrode
positions or they can be removed from an old cap and installed in a new
cap.
Sizes and layouts
Caps are available in a
wide range of sizes and with a variety of electrode position layouts:
|
Size |
Color |
Head Circ. |
# Sites |
Std. Layout |
Boys |
Girls |
|
Infa 6 |
Red |
22-26 cm |
32 |
10/20 |
premature infants |
|
Infa 5 |
Blue |
26-30 cm |
32 |
10/20 |
premature infants |
|
Infa 4 |
Yellow |
30-34 cm |
32 |
10/20 |
premature infants |
|
Infa 3 |
Brown |
34-38 cm |
64 |
10/20 |
0 - 1 mo. |
0 - 1.5 mo. |
|
Infa 2/3 |
Pink/Brown |
36-40 cm |
64 |
10/20 |
0 - 2 mo. |
.5 - 3 mo. |
|
Infa 2 |
Pink |
38-42 cm |
64 |
10/20 |
1 - 3.5 mo. |
1.5 - 5.5 mo. |
|
Infa 1/2 |
Lt Blue/Pink |
40-44 cm |
64 |
10/20 |
2 - 6.5 mo. |
3 - 9 mo. |
|
Infa 1 |
Light Blue |
42-46 cm |
64 |
10/20 |
3.5 - 10.5 mo. |
5.5 - 15.5 mo. |
|
X-Small/Infa 1 |
Green/ Light Blue |
44-48 cm |
64 |
10/20 |
6.5 - 19 mo. |
9 - 28 mo. |
|
X-Small |
Green |
46-50 cm |
128 |
10/20 or ABC |
10.5 - > 36 mo. |
15.5 - > 36 mo. |
|
Small/X-Small |
Yellow/Green |
48-52 cm |
128 |
10/20 or ABC |
19 - > 36 mo. |
28 - > 36 mo. |
|
Small |
Yellow |
50-54 cm |
256 |
10/20 or ABC |
toddlers / children |
|
Medium/Small |
Red/Yellow |
52-56 cm |
256 |
10/20 or ABC |
children / teens / small adults |
|
Medium |
Red |
54-58 cm |
256 |
10/20 or ABC |
teens / adults |
|
Large/Medium |
Blue/Red |
56-60 cm |
256 |
10/20 or ABC |
teens / adults |
|
Large |
Blue |
58-62 cm |
256 |
10/20 or ABC |
large teens / adults |
|
X-Large |
Brown |
62-66 cm |
256 |
10/20 or ABC |
exceptionally large adults |
Standard cap layouts for 16, 32 and
64 channels are based on the International 10/20 System. Layouts for 128,
160 and 256 channels have electrode positions that are radially equidistant from
CZ. Click on the images below to enlarge the view of each standard cap
layout diagram:
| 32 channels (10/20) |
64 Channels (10/20) |
128 Channels (equiradial) |
 |
 |
 |
| 160 Channels (equiradial) |
|
256 Channels (equiradial) |
 |
|
 |
The electrode
position coordinates of standard ActiveTwo head caps are available from the
downloads page.
Applying the head cap
The standard
steps for applying the head cap and electrodes are:
|
1 - Place
the cap on the subject's head. |
|
2 -
Fill the electrode holders with electrode gel from a
syringe. |
|
3 -
Insert the electrodes, taking care to match the
color-coded label on the electrode to that on the electrode holder. |
|
 |
|
 |
|
 |
Because of the characteristics of
the active electrode, high electrode impedance can be tolerated, so no skin
preparation is required. Thus, the usual, unpleasant and time-consuming
abrasion of the scalp is omitted. After the electrode holders are filled
with gel, the active electrodes are plugged in the cap one by one. The
procedure is fast and reliable, and allows high density EEG measurement with a
minimum of preparation time and subject discomfort.
It is also possible to pre-assemble
the head cap (insert electrodes into the electrode holders) and pre-gel the
electrodes for placement on subjects with shorter hair (e.g. infants).
This shortens application time by eliminating the need to apply gel and insert
electrode while the subject waits.
Custom head caps
Surgical-style caps with
slightly lower coverage on the sides and in the back of the head are available
upon request. The surgical-style cap incorporates an elastic band at the
lower border of the cap, which eliminates the need for a chin-strap or body
harness. The surgical style cap also provides slightly lower coverage in
temporal and occipital areas.
A special full-coverage
head cap (not pictured here) for use with 128 and 256 channel systems was
developed in conjunction with Dr. Scott Makeig and colleagues at the
Swartz Center for Computational Neuroscience
in La Jolla, CA. This cap provides coverage in the cheek and neck regions
that is expected to be useful for better identification of signals by means of
independent component analysis (ICA). For details about this special cap
configuration, contact
Dr. Scott Makeig.
Different electrode
layouts are possible on client specification. It is also possible to assemble
your own cap layout.
All ActiveTwo information
copyright © BioSemi
|
