To summarize, hypotonia is generally associated with flaccid dysarthria and damage to the LMN pathway, whereas hypertonia occurs with spastic, hypokinetic (when consistent), and hyperkinetic (when fluctuating) disorders, and is associated with damage to the indirect UMN pathway and/or the basal ganglia control circuit [3,12-13].
For dysarthria severity, post hoc tests indicated that the statistically significant ANOVA result ([F.sub.4,64] = 3.357, p = 0.02) was attributable to differences between the mixed flaccid-spastic and flaccid groups (p = 0.003) and between the spastic and flaccid groups (p = 0.005), wherein individuals with flaccid dysarthria had significantly lower severity scores than either of these groups.
Only one participant in the study had ratings of abnormal muscle tone for more than one task: an 18 yr-old female with mild flaccid dysarthria due to myotonic dystrophy received 4 out of 5 abnormally low tone ratings, all bilaterally.
Only one participant, with myotonic dystrophy and mild flaccid dysarthria, had clear and consistent ratings of abnormal muscle tone, including bilateral facial droop and lower than normal cheek and lip resistance.
Flaccid dysarthria is linked to LMN damage, which can lead to abnormally low resting muscle tension ("floppiness") and eventually muscle atrophy; therefore, those in the flaccid dysarthria group may have thinner tissue than the other cohorts  and thus stiffness measures may be artificially inflated at some thin muscle sites.