Download Scoring of Arousal

Scoring of Arousal
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EEG Arousal scoring rules
1.Subjects must be asleep, defined as 10 continuous seconds or more of the indications
of any stage of sleep, before an EEG arousal can be scored (Figs. 1 and 2). Arousal
scoring is independent of Rechtschaffen and kales epoch scoring (i.e. an arousal can
be scored in an epoch of recording, which would be classified as wake by
Rechtschaffen and Kales criteria).
2.A minimum of 10 continuous seconds of intervening sleep is necessary to score a
second arousal (see Rationale section for discussion of 10 seconds as minimum sleep
between arousals) (Figs. 3 and 4).
3.The EEG frequency shift must be 3 seconds or greater in duration to be scored as an
arousal (see Rationale section for discussion of 3 seconds as the arousal duration of 3
seconds as the arousal duration criteria) (Figs. 1,5 and 6).
4.Arousals in NREM sleep may occur without concurrent increases in submental
EMG amplitude ( Fig. 8 and 9)
5. Arousals are scored in REM sleep only when accompanied by concurrent increases
in submental EMG amplitude alone.
6. Arousals cannot be scored based on changes in submental EMG amplitude alone.
7. Artifacts, K complexes or delta waves are not scored as arousals unless
accompanied by an EEG frequency shift (as previously defined) un at least one
derivation. If such activity precedes an EEG frequency shift, it is not included in
reaching the 3-second duration criteria. When occurring within the EEG frequency
shift, artifacts or delta wave activity are included in meeting duration criteria (see
Rationale section for discussion of delta wave activity as an indicant of arousal)
(Figs. 10-12).
8. The occurrence of pen blocking artifact should be considered an arousal only if an
EEG arousal pattern is contiguous. The pen blocking event can be included in
reaching duration criteria (Figs. 13-15).
9. Noncurrent, but contiguous, EEG and EMG changes, which were individually less
than 3 seconds but together greater than 3 seconds in duration, are not scored as
arousals (Fig. 16)
10. Intrusion of alpha activity of less than 3 seconds duration into NREM sleep at a
rate greater than one burst per 10 seconds is not scored as an EEG arousal. Three
seconds of alpha sleep is not scored as an arousal unless a 10-second episode of
alpha free sleep precedes (Figs. 17 and 18).
11. Transitions from one stage of sleep to another are not sufficient of themselves to
be scored as EEG arousals unless they meet the criteria indicated above.
Cyclic Alternating Pattern(CAP)
• a marker of arousal instability
Identify
1. repetitive stereotyped EEG patterns
2. lasting <60 sec
3. separated by time-equivalent intervals of background activity
•
slow high voltage waves during
phase A
alternating with low voltage theta–delta activities during
•
phase B
simultaneous modifications of cardiorespiratory rate, motor activity & CSF pressure
Æ increased during phase A
decreased during phase B
An example of cyclic alternatin pattern in sleep stage 2
(phase A and the following phase B)
Temporal range
CAP sequence : 2–60s
non-CAP : absence of CAP for .60
non-CAP
CAP
non-CAP
The third phase A followed by non-CAP is not included in the CAP sequence
The top couple is scored as a single phase A being the interval,2 s.
The middle and bottom couples are scored as independent phase As
Phase A
•
•
•
•
•
•
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Delta bursts
Vertex sharp transients
K-complex sequences with or without spindles
Polyphasic bursts
K-alpha
Intermittent alpha
EEG arousals
Phase A subtypes
subtypes A1
•
A phases with
synchronized EEG patterns
(If present, EEG desynchrony occupies ,20% of the entire phase A duration. Subtype A1
specimens include delta bursts, K-complex sequences, vertex sharp transients, polyphasic
bursts with ,20% of EEG desynchrony.
a decline from adolescence (71%) to young adulthood (61%), middle age
(62%) and then a drop(47%)
subtypes A2
• A phases with desynchronized EEG patterns preceded by or mixed
with slow high-voltage waves
– (a mixture of slow and fast rhythms with 20–50% of phase A occupied by EEG
desynchrony. Subtype A2 specimens include polyphasic bursts with more than 20% but
less than 50% of EEG desynchrony
a moderate increase of muscle tone and/or cardiorespiratory rate.
increase from adolescence (20%) to young adulthood (28%), remain
quite stable throughout mature adulthood (27%) and then rise during
senescence (35%).
subtypes A3
•
A phases with desynchronized EEG patterns alone (transient activation phases
or arousals) or exceeding two thirds of the phase A length,
– Predominantly rapid low-voltage rhythms with > 50% of phase A occupied by EEG
desynchrony. Subtype A3 specimens include K-alpha, EEG arousals, and polyphasic
bursts with .50% of EEG desynchrony. A movement artifact within a CAP sequence is
also classified as subtype A3.
enhancement of muscle tone and/or cardiorespiratory rate
increase slightly from adolescence (9%) to young (11%) and mature (11%)
adulthood, and then rise during senescence (18%).
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