Parkinson’s disease significantly impacts speech, particularly affecting
phonemic groups like stop-plosives, fricatives, and affricates. However,
its objective impact on the different phonemic groups has been briefly
addressed in the past.
This study introduces a new model, called MARTA, built upon a Gaussian
Mixture Variational AutoEncoder with metric learning to measure the
disease’s impact on the phonemic grouping automatically and objectively.
MARTA was trained on normophonic speech before adapting it to
parkinsonian speech. The model effectively clusters phonemic groups
unsupervised and demonstrates enhanced discriminative power when
supervised using forced-aligned labels. Our findings reveal that beyond
the traditionally affected phonemes, Parkinson’s disease not only
affects stop-plosives, voiced-plosives, and nasals, but also
significantly impacts liquids, vowels, and fricatives, with the model
achieving a benchmarking 91% ± 9 discrimination capability. An in-depth
evaluation of the impact of the disease on the different phonemic groups
represents an advance in the current knowledge of its effects on the
speech, and has clear implications in the speech therapy of people with
Parkinson’s disease.
Moreover, regardless of the specific application domain presented, the
model introduced has potential downstream utility in assessing the
manner of articulation, whether influenced by other medical conditions
or certain dialectal variations.