1. Eliminating Noise in a Cerebral Function Monitor Signal
Group 14
Brian Snelling, JP Day, Colin Compas

2. Project Description Cerebral Functioning Monitor EEG Reading Affected
Machine
Leads
EEG Reading Affected
EMI
ECG
Physical Contact
Equipment Proximity

3. Device Description Cerebral Function Monitor
Continuously measures brain activity
Normal reading
Between μV
Impedance - Less than 20k ohms
Detects
Oxygen loss (HIE)
Drug side effects
Seizures
Used approx. once per month

4. Solutions Move other equipment Remove ECG signal Shield Device
Frequencies too high
Proximity
Remove ECG signal
Ranges Overlap
Shield Device
CFM is Licensed and Approved
Device Already has Shield
Shield Leads
Preliminary Testing
Options

5. CFM Tracings
EMI can lead a normal signal to resemble the abnormal signal which can lead to misdiagnosis of a baby’s cognitive function.
Normal tracing characterized by central band in the 10-40µV range with a normal sleep wake cycle
Abnormal tracing characterized by lower, narrow band of activity with spikes indicating burst suppression
Normal tracing affected by EMI

6. Phantom Scans
Phantom was a cantaloupe with a diameter of 14 in. and a weight of 2 lb. 4 oz.
Phantom test 1
Phantom test 2

7. Distance Data
Noise values measured (µV) for 3-D distances of Medfusion Syringe and Fusion Pump for the shown experimental design.

8. Initial Shield Initial shield was copper hot water heater tube.
Eliminated all noise seen in unshielded wires.
Now looking into acquiring medical grade copper shielding that can be used in the NICU.

9. Misdiagnosis
Baby in need of treatment due to CNS injury due to hypoxia but the CFM reading is persistently over 10 µV and appears normal, disqualifying the baby for therapy
Failure to prevent brain injury
Baby with no brain activity but in whom interference generates a wave
The baby is actually too severely injured to benefit from cooling yet because of a false signal would be cooled

10. Completed Work Isolated noise signal with melon
Collected Data
Used Medfusion Pump
Eliminated Noise Signal
Copper Tube
Crude Device
Contacted Ted Weiler
Head of R & D
Ruled out EMI causes
Will review our data
Generated 3D noise graph

11. Current Work Obtain medical grade copper mesh
Contact Dr. Wikswo
Characterize noise signal
Use signal generator
Work w/ Clinical Eng. Department
Contact Olympic Medical
Discuss lead shielding
Obtain list of “problem” devices
Dr. Walsh
Olympic Medical
Test other “problem” devices
Record noise signals

12. Future Work Rerun noise test with medical grade copper mesh shield
Use shield with signal generator to control output signal
Insulate copper mesh shield
Implement system in incubator
Test in NICU setting
Continue working w/ Olympic Medical

13. References
Vries L, Hellstrom-Westas L. Role of cerebral function monitoring in the newborn. Archives of Disease in Childhood, 2007;27.
Spitzer A. Neonatal Cerebral Function Monitoring. Neonatalogy Today, 2006;1:1-12.
Gluckman P, Wyatt J, et al. Selective head cooling with mild systemic hypothermia after neonatal encephalopathy: multi-centre randomized trial. Lancet. 2005;365:
al Naqeeb N, Edwards AD, Cowan FM, Azzopardi D. Assessment of neonatal encephalopathy by amplitude integrated electroencephalography. Pediatrics 1999; 103(6):1263–1271.
Archbald F, Verma UL, Tejani NA, Handwerker SM. Cerebral function monitor in the neonate. II: Birth asphyxia. Dev Med Child Neurol 1984; 26(2):162–168.
Greisen G. Tape-recorded EEG and the cerebral function monitor: amplitude-integrated, time-compressed EEG. J Perinat Med 1994; 22(6):541–546.
Thornberg E, Thiringer K. Normal pattern of the cerebral function monitor trace in term and preterm neonates. Acta Paediatr Scand 1990; 79(1):20–25.
Verma UL, Archbald F, Tejani NA, Handwerker SM. Cerebral function monitor in the neonate. I: Normal patterns. Dev Med Child Neurol 1984; 26(2):154–161.