Parkinsonism due to chronic manganese toxicity in Ephedrone users is associated with a characteristic mixed hypokinetic- dystonic dysarthria.
Robotic-flat procody, frozen articulation, inability to change pitch and laudness, contineous or whispering voicing, palilalia and pallidal mutism are the most distinguished perceptual features.
It is perceptually similar to the speech of PD patients after subthalamic nuclei Deep brain stimulation if electrodes placed medially (in pallidothalamic tract).
Perceptual speech analysis may be adjunct to the clinical assessment of chronic manganese toxicity.