Abstract
Auditory evoked potentials (AEPs) are an electrical
m a n i fe s t ation of the brain response to an auditory stimu
l u s. M i d - l at e n cy auditory evo ked potentials
(MLAEPs) and the coherent frequency of the AEP
a re the most promising for monitoring depth of a n a es
t h e s i a . MLAEPs show graded ch a n ges with incre asing
anaesthetic concentration over the clinical conc
e n t ration ra n ge. The latencies of Pa and Nb
lengthen and their amplitudes reduce. These changes
in fe at u res of wave fo rm are similar with both
inhaled and intravenous anaesthetics. C h a n ges in
latency of Pa and Nb waves are highly correlated to
a transition from awa ke to loss of c o n s c i o u s n e s s.
MLAEPs re c o rding may also provide info rm at i o n
about cereb ral processing of the auditory input, p rob
ably because it re flects activity in the tempora l
l o b e / p r i m a ry cort ex , sites invo l ved in sounds elab oration
and in a complex mechanism of implicit (non
declarative) memory processing. The coherent freq
u e n cy has found to be disrupted by the anaesthetics
as well as to be implicated in attentional mech a n i s m .
These results support the concept that the A E P s
re flects the balance between the arousal effects of
s u rgical stimu l ation and the dep ressant effects of
a n a e s t h e t i c s.H oweve r, AEPs are n’t a perfect measure
o f anaesthesia dep t h . Th ey can’t predict pat i e n t s
m ovements during surge ry and the signal may be
a ffected by mu s cle art e fa c t s, d i at h e rmy and other
electrical operating theat re interfe re n c e s. In concl us
i o n , once re l i ability of the AEPs re c o rding became
p roved and the signal acquisition improved it is like ly
to became a routine feature of clinical anaesthetic practice
Lingua originale | English |
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pagine (da-a) | 293-297 |
Numero di pagine | 5 |
Rivista | Minerva Anestesiologica |
Volume | 70 |
Stato di pubblicazione | Pubblicato - 2004 |
Keywords
- auditory evoked potentials