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Uncertainty in Multiclass Classification

Dr. Rishabh Pathak
1. What is Uncertainty in Classification? Uncertainty refers to the model’s confidence or doubt in its predictions. Quantifying uncertainty is important to understand how reliable each prediction is. In multiclass classification , uncertainty estimates provide probabilities over multiple classes, reflecting how sure the model is about each possible class. 2. Methods to Estimate Uncertainty in Multiclass Classification Most multiclass classifiers provide methods such as: predict_proba: Returns a probability distribution across all classes. decision_function: Returns scores or margins for each class (sometimes called raw or uncalibrated confidence scores). The probability distribution from predict_proba captures the uncertainty by assigning a probability to each class. 3. Shape and Interpretation of predict_proba in Multiclass Output shape: (n_samples, n_classes) Each row corresponds to the probabilities of ...
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Periodic Epileptiform Discharges Compared to ECG Artifacts

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Dr. Rishabh Pathak

Periodic Epileptiform Discharges (PEDs) can sometimes be confused with ECG artifacts due to their rhythmic nature. However, there are several distinguishing features that help differentiate between the two. 

Comparison of Periodic Epileptiform Discharges (PEDs) and ECG Artifacts:

1.      Waveform Characteristics:

§  PEDs: Typically exhibit a triphasic waveform, characterized by a sharply contoured initial spike followed by a slow wave. The morphology is consistent and can be recognized as a specific pattern associated with epileptiform activity.

§  ECG Artifacts: These may appear as sharp or rhythmic waves but do not have a consistent triphasic morphology. ECG artifacts can vary widely in appearance and may not follow a specific pattern.

2.     Location:

§  PEDs: Often localized to specific regions of the scalp, particularly in cases of focal brain lesions or encephalopathy. They can be bilateral but are usually maximal in one area.

§  ECG Artifacts: Typically manifest across multiple channels and may not be confined to a specific region. They often appear in a consistent pattern across the electrodes that are in contact with the heart.

3.     Inter-discharge Interval:

§  PEDs: Characterized by regular inter-discharge intervals, often occurring every 1 to 2 seconds. The timing is consistent and predictable.

§  ECG Artifacts: The intervals may be irregular and do not follow a predictable pattern. The timing of ECG artifacts can vary based on the patient's heart rate and other factors.

4.    Response to Movement:

§  PEDs: Generally do not change significantly with patient movement or external stimuli. They are intrinsic to the brain's electrical activity.

§  ECG Artifacts: Often increase in amplitude or change in morphology with patient movement, changes in position, or other external factors.

5.     Clinical Context:

§  PEDs: Associated with specific neurological conditions, such as encephalopathy, seizures, or brain lesions. Their presence is clinically significant and warrants further investigation.

§  ECG Artifacts: Typically arise from physiological processes related to the heart and are not indicative of neurological dysfunction. They are often considered noise in the EEG recording.

6.    Background Activity:

§  PEDs: Usually accompanied by low-amplitude background activity, which may be disorganized or show slowing.

§  ECG Artifacts: The background activity may remain unchanged, but the artifacts can obscure the underlying EEG signals.

Summary:

While both Periodic Epileptiform Discharges (PEDs) and ECG artifacts can present as rhythmic patterns on an EEG, they can be distinguished by their waveform characteristics, location, inter-discharge intervals, response to movement, clinical context, and accompanying background activity. Recognizing these differences is crucial for accurate interpretation of EEG recordings and appropriate clinical management.

 

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