  This study investigates the speech articulatory coordination in schizophrenia
subjects exhibiting strong positive symptoms (e.g.hallucinations and
delusions), using a time delay embedded correlation analysis. We show that the
schizophrenia subjects with strong positive symptoms and who are markedly ill
pose complex coordination patterns in facial and speech gestures than what is
observed in healthy subjects. This observation is in contrast to what previous
studies have shown in Major Depressive Disorder (MDD), where subjects with MDD
show a simpler coordination pattern with respect to healthy controls or
subjects in remission. This difference is not surprising given MDD is
necessarily accompanied by Psychomotor slowing (i.e.,negative symptoms) which
affects speech, ideation and motility. With respect to speech, psychomotor
slowing results in slowed speech with more and longer pauses than what occurs
in speech from the same speaker when they are in remission and from a healthy
subject. Time delay embedded correlation analysis has been used to quantify the
differences in coordination patterns of speech articulation. The current study
is based on 17 Facial Action Units (FAUs) extracted from video data and 6 Vocal
Tract Variables (TVs) obtained from simultaneously recorded audio data. The TVs
are extracted using a speech inversion system based on articulatory phonology
that maps the acoustic signal to vocal tract variables. The high-level time
delay embedded correlation features computed from TVs and FAUs are used to
train a stacking ensemble classifier fusing audio and video modalities. The
results show that there is a promising distinction between healthy and
schizophrenia subjects (with strong positive symptoms) in terms of neuromotor
coordination in speech.
