16th Annual Conference of the International Speech Communication Association

Dresden, Germany
September 6-10, 2015

Vocal Tremor Analysis via AM-FM Decomposition of Empirical Modes of the Glottal Cycle Length Time Series

Christophe Mertens (1), Francis Grenez (1), François Viallet (2), Alain Ghio (3), Sabine Skodda (4), Jean Schoentgen (1)

(1) Université Libre de Bruxelles, Belgium
(2) Centre Hospitalier du Pays d'Aix, France
(3) LPL, France
(4) Ruhr-Universität Bochum, Germany

The presentation concerns a method that obtains the size and frequency of vocal tremor in speech sounds sustained by normal speakers and patients suffering from neurological disorders. The glottal cycle lengths are tracked in the temporal domain via salience analysis and dynamic programming. The cycle length time series is then decomposed into a sum of oscillating components by empirical mode decomposition the instantaneous envelopes and frequencies of which are obtained via an AM-FM decomposition. Based on their average instantaneous frequencies, the empirical modes are then assigned to four categories (intonation, physiological tremor, neurological tremor as well as jitter) and added within each. The within-category size of the cycle length perturbations is estimated via the standard deviation of the empirical mode sum divided by the average cycle length. The tremor frequency within the neurological tremor category is obtained via a weighted instantaneous average of the mode frequencies followed by a weighted temporal average. The method is applied to two corpora of vowels sustained by 123 and 74 control and 456 and 205 Parkinson speakers respectively.

Full Paper

Bibliographic reference.  Mertens, Christophe / Grenez, Francis / Viallet, François / Ghio, Alain / Skodda, Sabine / Schoentgen, Jean (2015): "Vocal tremor analysis via AM-FM decomposition of empirical modes of the glottal cycle length time series", In INTERSPEECH-2015, 766-770.