Over the last several years, several feature extraction techniques have been introduced. In general, all the feature extraction methods utilize one of the following three signal representation domains: temporal domain, spectral or joint time-frequency (TF) domain. In this seminar, advantages and challenges associated with feature extraction from temporal and spectral domains will be discussed. Spectral features generally assume the stationarity of the signal in the analysis frame, and do not provide any information on the temporal evolution or localization of the
extracted features. The talk will cover the recent advancements in TF feature extraction using methods based on adaptive signal representations such as pursuits-based. The application of the extraction and classification of complex instantaneous
signal parameters with respect to real world biomedical signals such as cardiac electrograms and brain electroencephalogram signals will be discussed.
Deep Generative Learning for All - The Gen AI Hype (Spring 2024)
Biomedical Signal Extraction for Computer-assisted Clinical Decision Making - Dr. Behnaz Ghoraani - WiDS Miami 2018
1. Behnaz Ghoraani, Ph.D.
Assistant Professor
Florida Atlantic University
Computer and Electrical Engineering
Biomedical Signal Feature Extraction for Computer-assisted
Clinical Decision Making
Biomedical Signal and Image Analysis Lab
2. Agenda
— Signal Processing andAnalysisTools
— Research Projects at BSIA Lab
— Atrial Fibrillation
— Artifact Reduction inAuditory Evoked Potentials
— AutomaticAssessment of Medication States of Patients with
Parkinson’s Disease usingWearable Sensors
— Automatic Localization of Epileptic Spikes in EEGs of Children
with Infantile Spasms
Talk @WDSC 20182
3. Signal Analysis/Information Extraction/Decision Making
Feature
Extraction
Classifier
Trained
Classifier
Training Phase
Classification Phase
Classification Result
Sensor
Classification Scheme
Train
Features
Test
Features
Signal
Processing
Talk @WDSC 20183
4. -2 -1.5 -1 -0.5 0 0.5 1 1.5 2
0.5
1
1.5
2
2.5
3
Decision Making (Cont.)
— What is Signal classification?
Talk @WDSC 20184
13. Time – frequency map (TF tiling)
time
frequency
time
frequency
fr
tr
fr
tr
Heinsenberg’s boxes
Talk @WDSC 2018
FT
TF
13
14. Wavelets – Using a known small wave estimating an unknown signal
CWTx
ϕ
(τ,s) =
1
s
. x(t).w
t −τ
s
"
#
$
%
&
'dt∫
s
s
S=1/f
t1 t2 t3 t3
…. s1,s2,s3,s4………………
Mother wavelet
Talk @WDSC 201814
15. F>> F<<
S<< S>>
In Wavelets ‘scale’ is inversely tied to the ‘frequency ‘
time
Scaling
Wavelets
• Good time resolution and poor freq resolution at
higher frequencies
• Poor time resolution and good freq resolution at
lower frequencies.
freq
Time – frequency map (TF tiling) - Wavelets
s= window size
Variable, but restricted resolution constraints !!!Talk @WDSC 201815
17. Wigner-Ville distribution
Wx (t,ω)= x(t).x(t +τ).e− jωt
dτ∫
It is nothing but the Fourier transform of the auto correlation
of the signal. In other words it is same as STFT where the
window function is nothing but the signal itself !!
So far the best TF resolution is achieved only by Wigner-Ville.
Talk @WDSC 201817
18. Signal
What did we achieve ?
timetime
Wigner-ville
Cross terms
Talk @WDSC 201818
19. Why do we have cross terms ?
Wx (t,ω)= x(t).x(t +τ).e− jωt
dτ∫
(a+b) = multi component signal
x(t) . X(t+l) (a+b) (a+b) ( a2+b2+2ab)
( a2+b2+2ab)
“ CROSS TERMS ”Talk @WDSC 201819
21. How to solve this restricted resolution problem ?
An adaptive technique is needed, which should alter
its TF tiling to any resolution !
“ Adaptive Signal Decompistion”
“A Pursuit in search for the best
TF localized match”
Talk @WDSC 201821
22. Redundant dictionary
of TF functions for all
values of translation,
scaling and modulation
Signal projection
over the TF dictionary
After ‘m‘ iterations
Original signal
‘m’ TF functions + Signal residue
Matching Pursuit
Talk @WDSC 201822
23. In MP the scaling parameter is independent of frequency
time
Scaling
freq
This approach is much more adaptive with
no restrictions on windowing patterns .
s
s
Still the dictionary selection limits complete modeling of the signal
Matching Pursuit
Talk @WDSC 201823
31. TF Features
— Joint TF Moments
— Sparsity
— Discontinuity
— Coherency
Classifier
W
H
)(tx
V Matrix
Decomposition
TFD
Feature
Extraction
Talk @WDSC 201831
32. TF Feature Example
— 3-second audio signal
— TFD with 512 and 2048 frequency and time bins.
— TFM:
— TFM decomposition:
— TFM Features:
2048512´V
15512´W 204815´H
{ }MPDDSSMOMO whwhwh ,,,,,, )1()1(
Talk @WDSC 201832
33. Extension to Multi-channel Signals
Ankle
Ankle
Trunk
Time (s)
Frequency (Hz)
Sensors
Wrist
TrunkWrist
Talk @WDSC 201833
34. Tensor Decomposition
— Canonical Polyadic Decomposition (CPD)
— Decomposition to rank-1 components
— Rank-1 decompositions are the 𝒂𝒊, 𝒃𝒊 and 𝒄𝒊 where 𝑖 ∈
1,2,3, … 𝑹;
𝑨, 𝑩 and 𝑪 are Factor Matrices
Talk @WDSC 2018
T +⋯+ =
𝒂 𝟏
𝒃 𝟏 𝒃 𝑹
𝒂 𝑹
𝒄 𝟏 𝒄 𝑹
𝑨
𝑩
𝑪
≈
34
35. Some of the Research Projects @ BSIA Lab
35 Talk @WDSC 2018
36. Current BSIA Lab Projects
— Atrial Fibrillation (AF)
• Catheter guidance in AF ablation
• AF detection from surface ECG
• Risk detection in external DC cardioversion
• Scar quantification in endocardium duringAF
• Scar quantification in LA from delayed-enhance
MRI
— Sudden Cardiac Death (SCD)
• Risk stratification of SCD
• 3D distribution of stress inducedTWA
— Artifact Rejection of EEGAuditory Evoked
Potential
— Quantification of Hypsarrhythmia in
Infantile Spasms
• Temporal and Spectral quantification of
EEG
• Epileptic discharge detection from EEG
— Parkinson’s Disease
— Automated detection of medication off
vs. dyskinesia from ambulatory gate data
in PD patients
— Structure-constrained Basis Pursuit For
Compressed Sensing
— Real-time Speech Recognition Using
Compressively Sensed Samples
— TF feature extraction using Dictionary
learning
Talk @WDSC 201836
37. Atrial Fibrillation
— Among these heart problems, atrial fibrillation (AF) is the
most common heart rhythm disorder that affects millions of
people, accounting for frequent hospitalizations, increased
risks of stroke, heart failure and mortality.
Talk @WDSC 201837
38. • QRS Complex
• Represents contraction of
the ventricles
• T Wave
• Represents relaxation of
the ventricles
Electrocardiogram
• PWave
• Represents contraction of the atria
Talk @WDSC 201838
43. AF Projects
— Identifying Atrial Fibrillation Episodes from ECG recordings.
— Developing a New Computer-aided Clinical Decision
Support System For Prediction of Successful Post-
cardioversion PatientsWith Persistent Atrial Fibrillation.
Talk @WDSC 201843
44. Computer-aided Clinical Decision Support System For
Prediction of Successful Post-cardioversion Patients
With Persistent Atrial Fibrillation
Talk @WDSC 201844
Overall outline of the study. Standard supervised learning approach is applied
consisting of a feature extraction step followed by a classification step. Leave-
one-out cross validation is used to evaluate the predictive power of our
technique.
48. Results
Talk @WDSC 201848
Dataset: 40 persistent AF patients who had a successful external DCE
cardioversion therapy. Prior to cardioversion, a10-minute 12-lead ECG was
recorded. Twenty patients had maintained SR (AF-Free) after 2-week follow-up and
20 had a relapse of AF (AF-Relapse).
Receiver operating characteristic
analysis using leave-one-out cross
validation. The AUC is 0.97 and the
best sensitivity and specificity are
100% and 95%, respectively.
49. EEG Auditory Evoked Potentials
Talk @WDSC 201849
Latency – neural conduction/processing time
Amplitude – strength/magnitude of response
52. Talk @WDSC 2018
D. Sinkiewicz, L. Friesen and B.
Ghoraani,“Analysis of Cochlear
Implant Artifact RemovalTechniques
Using the ContinuousWavelet
Transform”, in the proceedings of the
36th Annual International IEEE EMBS
Conference, Pages: 5482-5485,
September, 2014.
D. Sinkiewicz, L. Friesen, and
B. Ghoraani,“A Novel Method for
Extraction of Neural Response from
Cochlear Implant Auditory Evoked
Potentials”, MEP Journal, December
2016.
52
53. Parkinson’s Disease
— Parkinson disease (PD) is a chronic progressive neurological
disorder that will affect over half a million Americans by
2030.
— A chronic progressive neurological disorder that leads to
different motor and non-motor disabilities.
— Bradykinesia: impairment of the power of voluntary movements
that leads to slow movements.
— Tremor: consists of hand and leg tremor while resting.
— Dyskinesias: Uncontrolled muscles movements that is induced
by levodopa with long-term medication.
Talk @WDSC 201853
54. 54
OFF and ON States for One ofThe Patients
Dataset
Talk @WDSC 2018
55. Translating Multidimensional Sensor Data to Guide
Self-management for Patients with Parkinson
Disease
Talk @WDSC 201855
1
2
Deep Brain Stimulator/
Drug Infusion Pump
Body-worn
Inertial Sensors
Developed Algorithm
Before medication
(OFF)
UPDRS-49; mAIMS=5
1 hour after medication
(partial ON)
UPDRS=30; mAIMS=7
2 hours after medication
(ON with dyskinesia)
UPDRS=17; mAIMS=16
3 hours after medication
(OFF again)
UPDRS=42; mAIMS=4
ON
OFF
40 sec
Classification
Certainty
RTI Status Report
Existing
Devices/Algorithms
Motor Impairment Report
Clinical Visits For
Physician Interpretation
3
a
b
c
d
Clinically
Actionable
Information
Front Back
58. Classification Report
Talk @WDSC 201858
M. Hssayeni, M. Burack , J.Adams, B. Ghoraani “Personalized Assessment of Response to
Therapeutic Intervention in Individuals with Parkinson's Disease”, under preparation to the
IEEETransactions on Biomedical and Health Informatics.
60. Infantile Spasms
— Quantification of Hypsarrhythmia in Infantile Spasms
Talk @WDSC 2018
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Traitruengsakuly S, Seltzerz LE, Paciorkowskiz AR, Ghoraani B.
Automatic Localization of Epileptic Spikes in EEGs of Children with
Infantile Spasms, 37th IEEE Engineering In Medicine and Biology Proceedings:
6194- 6197.August 2015, Milan, Italy.60
61. TF Feature Extraction
Talk @WDSC 2018
0 0.2 0.4 0.6 0.8 1
0
0.2
0.4
0.6
0.8
1
False Positive Rate (1−specificity)
TruePositiveRate(sensitivity)
(b) ROC based on F2
AUC = 98.56% ( = 10)
AUC = 93.14% ( = 0.5)
Classification Performance
Using SupportVector Machine
S.Traitruengsakul, L. E. Seltzer,A. R. Paciorkowski, and B. Ghoraani,
“Developing A Novel Epileptic Discharge LocalizationAlgorithm for
Electroencephalogram Infantile Spasms During Hypsarrhythmia”, Medical
& Biology Engineering and Computing Journal, January 2017.
61
62. Some of the members of BSIA Lab
Talk @WDSC 201862
63. q Dr. Moussa Mansour,
Massachusetts General
Hospital
q Dr. Jamie Adams, University
of Rochester Medical Center
q Dr. Michelle Burack,
University of Rochester
Medical Center
q Dr. David Huang, University of
Rochester Medical Center
q Dr. Lendra Friesen, University
of Connecticut
q Dr. Laurie Seltzer, Neurology,
University of Rochester
Medical Center
q Dr. Elizabeth M. Cherry,
School of Mathematical
Sciences, RIT
q Dr. Arkady M. Pertsov, SUNY
Upstate Medical University
School of
Mathematical
Sciences
RIT
q National Institutes of Health
(NIH) - 1R15HL127663-01
q NSF Advance - HRD-1209115.
q I-SENSE Seed Funding
63 Talk @WDSC 2018