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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

02 📊

Extract

Acoustic features & MFCCs

03 📈

Baseline

Within-subject reference

04 🔍

Analyze

Statistical deviation

05 📥

Export

PDF 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.

+2.58 SD Mean -2.58 SD ● Outside 99% range Recording 1 30

Repeated recordings provide an individual baseline. Subsequent measurements can be compared to detect statistically unusual deviations.

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 Z-score values are shown when sufficient within-subject reference data are available. A ±2.58 threshold corresponds approximately to the central 99% range of a normal distribution and is provided for exploratory reference only.

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.

Epilepsy Voice Research

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

Longitudinal Monitoring

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

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.

Signal Processing

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

Feature Extraction

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

Full methodology →

Within-Subject Baseline

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

Statistical Analysis

Z-score-based deviation detection with a 99% reference range (±2.58 SD) where applicable. Values outside this range may be flagged for review.

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.

Audio Storage

Raw audio files are processed and numerical metrics are stored. Audio retention policies should be verified in the current platform documentation.

Data Export

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

De-Identification

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

Data Security

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

Privacy Policy →

Get Started with Your Research

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