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Quantitative Voice Features for Longitudinal Research

Extract acoustic and MFCC features from voice recordings to characterize within-subject changes over time. Designed for observational studies and epilepsy voice-biomarker research.

How It Works

A simple workflow for longitudinal voice research.

01 🎙️

Record

Voice sample via mobile or web app

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02 📊

Extract

Acoustic features & MFCCs

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03 📈

Baseline

Within-subject reference

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04 🔍

Analyze

Longitudinal comparison

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05 📥

Export

CSV for independent analysis

Extracted Features

Each recording generates a feature set for exploratory longitudinal research.

F0

Pitch

Mean & variability

Methodology →
J

Jitter

Period perturbation

Methodology →
S

Shimmer

Amplitude perturbation

Methodology →
H

HNR

Harmonics-to-noise ratio

Methodology →
F

Formants

F1, F2, F3 midpoint

Methodology →
Δ

Spectral Features

Centroid, bandwidth, rolloff

Methodology →
A

Formant Variability

F1/F2 variability index

Methodology →
C

F0 Split-Half

Within-recording consistency

Methodology →
R

Low/Mid Correlation

Spectral band similarity

Methodology →
MF

MFCCs

13 cepstral coefficients

Methodology →

Longitudinal Analysis

Monitor change within a participant over time.

Mean Recording 1 30

Repeated recordings provide an individual reference. Subsequent measurements can be compared to characterize within-subject change over time.

Sample Output

Example of the data provided for each recording (simulated for demonstration).

Recording-Level Analysis

Each recording generates a feature set with optional within-subject baseline comparison.

Metric Current Value Baseline Z-score
Pitch Mean (F0) 152.3 Hz 148.7 Hz +0.31
Pitch Variability 22.4 Hz 19.8 Hz +0.87
Jitter 0.031 0.028 +0.52
Shimmer 0.082 0.075 +0.44
HNR 18.3 dB 20.1 dB -0.65
Temporal Variation 0.021 0.018 +0.29
Spectral Centroid 2147 Hz 2098 Hz +0.38
Formant Variability Index 412.6 389.2 +0.71
F0 Split-Half Consistency 0.89 0.92 -1.02
Low/Mid Spectral Correlation 0.67 0.71 -0.53

⚠️ Baseline and standardized deviation values are shown when sufficient within-subject reference data are available. Interpretation of individual values should follow the study protocol and the technical methodology.

All values shown are synthetic examples created for interface demonstration only. They do not represent measurements from an actual participant or validated clinical reference dataset.

Research Applications

Cogitrac Voice is designed for epilepsy research and longitudinal voice studies.

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Epilepsy Voice Research

Explore quantitative changes in voice features in epilepsy research cohorts and longitudinal studies.

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Longitudinal Monitoring

Track within-subject voice changes over time using an expanding reference. Designed for observational studies.

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Data Collection & Export

Collect voice data and export metrics as CSV for independent analysis in R, Python, or other statistical software.

Methodology & Validation

Cogitrac Voice is an investigational platform. Validation is in progress.

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Signal Processing

Voice samples are processed using Parselmouth/Praat and Librosa. Preprocessing includes RMS-based quality checks and pulse detection.

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Feature Extraction

F0, jitter, shimmer, HNR, formants, spectral features, and 13 MFCCs are extracted and retained as candidate variables.

Full methodology →
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Within-Subject Reference

Individual references are established from repeated recordings. The number of recordings required should be determined by the study design and analysis plan.

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Analysis Framework

The platform supports exploratory within-subject analysis where sufficient longitudinal data are available. Specific analytical procedures and parameters are documented in the technical methodology and available to qualified researchers under appropriate confidentiality agreements.

Investigational research platform. Cogitrac Voice is not FDA-cleared, not clinically validated, and not intended for diagnosis, treatment, seizure prediction, or clinical decision-making. Individual features should not be interpreted as diagnostic, prognostic, treatment-related, or clinically actionable measurements. Always consult a qualified healthcare provider for any health-related decisions.

Data & Privacy

Researchers and participants retain control over their data.

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Audio Storage

Raw audio is not retained. Recordings are processed on upload and the audio is deleted immediately after feature extraction. Only the derived numerical metrics are stored.

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Data Export

Export metrics as CSV for independent analysis. Raw audio is not included in standard exports.

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De-Identification

Research data is de-identified and can be retained for ongoing studies. Participants can manage recordings through the platform.

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Data Security

Data is encrypted in transit and at rest. Access is restricted to authorized research personnel.

Privacy Policy →

Get Started with Your Research

Create an account to explore the platform.