The document discusses the cerebral function monitor (CFM), also known as amplitude-integrated EEG. The CFM is a device that measures brain activity through a single lead placed on the head. It was initially developed in the 1960s for adults but was later introduced for neonates in the 1980s. The CFM can help detect seizures, monitor the effects of drugs/therapy, and aid in predicting outcomes for conditions like hypoxic-ischemic encephalopathy. It provides a simplified view of brain activity through amplitude and variability measurements. General patterns seen include normal/abnormal voltage levels and the presence/absence of sleep-wake cycling.

1. BY
AHMED GALAL OKASHA
AL JAHRA NICU

2.  Cerebral
Function
Monitor
(CFM),or
An
amplitudeintegrated EEG, is a device used
to
measure
background
electrocortical activity in the
brain.
 The cerebral function monitor
provides information on global
cerebral activity. to indicate the
generalized level of electrical
activity occurring across the
entire brain.

3.  CFM technology was initially developed in the 1960s
for adults suffering from neurological depression or
injury or undergoing surgery.
 technology was introduced in the mid 1980s by
neonatologists. Research showed it could be a sensitive
tool for predicting severity of hypoxic-ischemic
encephalopathy, if applied in the first 6–12 hours
following perinatal asphyxia.

4.  this mean it has predictive value on acute neurological
conditions and long term neurodevelopmental outcome.
 The CFM has also demonstrated itself as a valuable
detection tool for neonates with clinical or subclinical
seizures.

5. Intended use of CFM
 Continuous monitoring and recording of brain
activity.
 Aiding detection and treatment of siezures.
 Monitor the effect of the drugs and other therapy
in the brain.
 Aiding in identifying the HIE and predicting the
long- term outcome.
 Improving the accuracy of neonatal neurological
examination

6. Indications:
• Hypoxic – Ischemic Encephalopathy
• Seizures or clinical scenario mimicking seizure
disorders (e.g., apnea, hypertension, tachycardia)
• Significant neurological disorders (e.g., congenital
brain malformations, vascular lesions)
• Post cardiac arrest
• Inborn error of metabolism (e.g., urea cycle disorders,
hypoglycaemia, hypocalcaemia)
• Neonatal abstinence syndrome (e.g., alcohol/opiate
withdrawal)

7. Principle of CFM
 Using a single lead (single channel), consisting of three
wires placed over the biparietal or frontal region;
 the
machine
filters,
rectifies
compresses the electric brian signal.
and

8.  Filtering and rectifying
mean Frequencies <2 and >15 Hz are selectively
filtered to reduce artefacts caused by movement, ECG
and other electronic equipment.

9. Compression
 mean time compression The signal is displayed on an
x-y axis, using a very slow chart speed (6 cm/h).
 The CFM focuses on changes in amplitude in the EEG
— it is referred to as aEEG — amplitude-integrated
EEG.
 The amplitude of the trace can be
assessed by measuring the upper and lower margins of
the trace against.

10. Applying electrodes
Placement
• Biparietal is the optimal location this is the
watershed area between the posterior and middle
cerebral arteries. This area is least likely to be affected
by scalp muscle activity and eye-movement artifacts.

13. Impedance
 Measures quality of electrode contact and should be
 as low as possible. It is also used to detect lead motion
artifact.
 The CFM 6000 monitor will Alarm if > 20kΩ.

14.  Hydrogel electrodes — can be used on scalp
(biparietal) or forehead Requires aggressive
preparation for cleaning to assure adequate adherence.
These electrodes should be replaced every 24 hours.
 Low-impedance needle electrodes
Insert sub-dermally in parietal position These
electrodes can be left in place for days, if needed.

15. General interpretation
• Presence of Sleep/Wake cycle
• Amplitudes of the upper and lower margins of the trace
— in micro-voltage (μV)
• Variability — narrow or broad trace.
• Brain Activity
Continuous (normal) — dark central band of
continuous activity, with normal amplitudes
Discontinuous (abnormal) — a wide trace with no
central band of activity; appears universally gray
• Presence of seizure activity

16. • Continuous normal voltage (CNV) — a narrow
band on the aEEG with dark central band
indicating a continuous normal high level of
activity with little variability

17.  Discontinuous normal voltage (DNV) — a wide
band on the aEEG that appears universally gray,
indicating increased variability in activity
primarily due to intermittent lower levels of
activity

18. Understanding aEEG
Quiet/active cycling — also known as sleep/wake cycle
— trace is narrow when infant is awake (or in active
sleep) and widens during quiet sleep; typically cycles
every 90 min, but is dependent on infant condition.
Early return of sleep wake cycling (SWS) after an
asphyxial insult is also a good prognostic sign.

19.  • Flat EEG — a relatively flat trace at the bottom of
the aEEG scale

20. Burst suppression (BS) — a comb like pattern in the
aEEG due to
A severely abnormal trace is characterised by a general
suppression of amplitude so that the trace appears
narrow and of low voltage.
may be accompanied by brief bursts of higher voltage
spikes, which appear as single spikes above the
background activity.
usually seen with severe encephalopathy and
often accompanied by seizure activity.

21. seizures
can be detected if there is sudden(rising and
narrowing) in the aEEG.
Status epilepticus = continuous seizures ≥ 30 min.

22.  It is important to inspect the underlying EEG
 to confirm the presence of seizures .
 distinguish artifacts from real signal.

23.  underlying EEG usually shows a repetitive spike and
wave discharge .
 Seizures may only be identified if they are sufficiently
prolonged, more than 2-3 minutes. Shorter lasting
discharges may be missed since the CFM is recorded at
a very slow speed.

24. Classification of the CFM
1. Normal
 The upper margin of the trace is above 10 microvolts
and the lower margin is greater than 5 microvolts.
 sleep/wake cycling.
 the width of the trace varies from approximately 10-40
microvolts.

25. Normal CFM voltage. Sleep wake cycling can be observed.
Movement artefact is present in part of trace.

26. 2. Moderately abnormal
The upper margin of the trace is greater than 10
microvolts and the lower margin is less than 5
microvolts. No SWC.
This appearance can be seen in infants with:
 moderately severe encephalopathy.
 immediately after administration of drugs such as
anticonvulsants and sedatives.
 This pattern may also be seen in preterm infants
(below 36 weeks gestation).

27. Severely abnormal
The upper margin of the trace is less than 10
microvolts. The lower margin is usually less than 5
microvolts
Presence of burst suppression spikes.
No sws.(FLAT TRACE)
seen with severe encephalopathy and often
accompanied by seizure activity.

28. Scoring Prediction of HIE Outcome
and

29.  Points to Note
 Focal abnormalities in the EEG may not be identified
because the .signal is obtained from a single channel.
 If the CFM trace looks odd or is not consistent with
the clinical picture use the EEG display facility on the
CFM to check for artefacts.
 Movement artefact associated with head bobbing due
to breathing
 position of the head or supporting the head with a roll
may lessen the artefact.

30.  Pulse artefact may be difficult to distinguish from
seizure on the EEG. The pulse artefact is regular with
the pulse. Place the electrode away from the fontanelle
may help.
 Medications may affect the record. Anticonvulsants or
sedatives such as morphine or chloral hydrate may
transiently suppress the CFM record. So
Administration of drugs or other clinical events should
be marked to

31. Pitfalls to watch for
• Background voltage appears elevated — Possible causes:
• ECG artifact
• Handling
• Muscle activity
• High-frequency ventilation
• Status epilepticus
• Gasp artifact
• Background voltage appears depressed — Possible causes:
• Severe scalp edema
• Leads significantly too close together
• Significant sedation