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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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Types of Phantom Spike and Wave

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Dr. Rishabh Pathak

Phantom Spike and Wave (PhSW) can be categorized into different types based on specific features such as amplitude, location, gender of the patient, and the state of wakefulness. The two primary forms of PhSW are often referred to by the acronyms WHAM and FOLD. 

1. WHAM (Waking, High amplitude, Anterior, usually Male)

    • Characteristics:
      • Waking State: This form typically occurs during wakefulness.
      • High Amplitude: The spikes in this pattern are defined as having a high amplitude, generally greater than 45 μV.
      • Anterior Location: The discharges are predominantly recorded from the frontal regions of the scalp.
      • Demographics: More commonly observed in male patients.
    • Clinical Context:
      • WHAM patterns may be associated with various neurological conditions and can indicate significant underlying pathology, particularly in males during awake states.

2. FOLD (Female, Occipital, Low amplitude, Drowsy)

    • Characteristics:
      • Drowsy State: This form is typically observed during drowsiness or light sleep.
      • Low Amplitude: The spikes are of lower amplitude compared to WHAM, often less than 40 μV, making them sometimes difficult to discern.
      • Occipital Location: The discharges are predominantly recorded from the occipital regions of the scalp.
      • Demographics: More commonly seen in female patients.
    • Clinical Context:
      • FOLD patterns are often associated with benign conditions and may be seen in patients with a history of migraines or other non-epileptic phenomena. They are generally considered to have a better prognosis compared to WHAM patterns.

Summary of Differences

Feature

WHAM

FOLD

State

Waking

Drowsy

Amplitude

High amplitude (≥ 45 μV)

Low amplitude (< 40 μV)

Location

Anterior (frontal regions)

Occipital (occipital regions)

Demographics

Usually Male

Usually Female

 

Additional Notes

    • Prevalence: PhSW is relatively uncommon, occurring in about 0.5% to 1% of EEGs, but its occurrence is slightly more likely in females overall.
    • Age Range: The pattern is most likely to occur during adolescence and young adulthood, with a higher occurrence rate in this demographic.

Understanding these types of Phantom Spike and Wave patterns is crucial for clinicians in diagnosing and managing patients with neurological symptoms, as they can provide insights into the underlying conditions and their potential implications.

 

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