APPENDIX B –BASELINE MODE
58
D-0115696-C (OM038)
– Otowave 302 Operating Manual
11.3.
1000 HZ TYMPANOMETRY
11.3.1.
SCALAR MODE – Y-COMPENSATION
For 1 kHz operation a similar scalar display mode is available as used for 226Hz (Y-only compensation). This
mode is generally preferred when testing very young children.
2S MODE
4S MODE
11.3.2.
VECTOR MODE – B-G-COMPENSATION
For 1 kHz operation an alternative display mode is available known as
VECTOR
mode (based on definition in
Clause 3.17.2 of IEC 60645-5) and takes account of phase information in the measurements. It is also known
as B-G compensation and is suitable for all patients other than neonates.
The format is similar to that used for scalar mode with the 1 kHz probe tone. Baseline offsets of +200 daPa
offset (2V) and -400 daPa (4V) are available as required.
2V MODE
4V MODE
Please note
that a consequence of the vector mode calculation is that the resulting tympanogram
cannot take negative values. It is thus theoretically possible for the trace to appear to rise (i.e. take higher
positive values) at the end opposite to the selected offset. The user is advised to view traces with each of
the +200daPa and -400daPa baseline offsets selected before deciding which result to save.
11.3.3.
COMPONENT MODE – YBG
The Otowave 302 also provides a component display when using a 1 kHz probe tone where separate
uncompensated Y, B and G traces can be shown. These may help to interpret the tympanograms and help to
define the middle-ear pressure in cases where the Y display alone gives misleading or ambiguous conclusions.
The function is suitable for all patients. Component mode is used as required by the audiologist. In this case
the ear canal volume is measured at the +200daPa baseline offset in Scalar mode.
Admittance Y
Susceptance B
(imaginary part of admittance vector)
Conductance G
(real part of admittance vector)
