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. Author manuscript; available in PMC: 2019 Jul 16.
Published in final edited form as: Clin Linguist Phon. 2019 Apr 15;33(8):679–706. doi: 10.1080/02699206.2019.1595731

Table 2.

The five speech classifications and five motor speech classifications in the SDCS are each mutually exclusive. The five dysarthria subtype classifications are not mutually exclusive. That is, a speaker can meet percentile criteria for more than one of the five listed dysarthria subtype classifications (i.e., mixed dysarthria). See Supplement for the procedures and measures used to classify each motor speech disorder.

SDCS Classifications and Dysarthria Subtypes Abbreviation Age (yrs;mos) at Assessment Description Referencesa
Five Speech Classifications
 Normal(ized) Speech Acquisition NSA 3–80 Does not meet criteria for any of the four Speech Disorder classifications 2, 3, 4
 Speech Errors SE   6–8;11 Age-inappropriate speech sound distortions 3, 4
 Persistent Speech Errors PSE 9–80 Age-inappropriate speech sound distortions that persist past 9 years of age 4, 5
 Speech Delay SD   3–8;11 Age-inappropriate speech sound deletions and/or substitutions 3, 4
 Persistent Speech Delay PSD 9–80 Age-inappropriate speech sound deletions and/or substitutions that persist past 9 years of age 3, 4, 5
Five Motor Speech Classifications
 No Motor Speech Disorder No MSD 3–80 Does not meet criteria for any of the four Motor Speech Disorders classifications 2, 6, 8
 Speech Motor Delay SMD 3–80 Meets PSI criterion for SMD 2, 6, 8
 Childhood Dysarthria CD 3–80 Meets DI and DSI criteria for CD 2, 6, 8
 Childhood Apraxia of Speech CAS 3–80 Meets PM criterion for CAS 6, 7, 8
 Childhood Dysarthria & Childhood Apraxia of Speech CD & CAS 3–80 Meets SDCS criteria for CD & CAS 2, 6, 8
Five Dysarthria Subtypes
 Ataxic 3–80 Cerebellar disorder 1, 2
 Spastic 3–80 Upper motor neuron disorder 1, 2
 Hyperkinetic 3–80 Basal ganglia disorder; increased movement 1, 2
 Hypokinetic 3–80 Basal ganglia disorder; decreased movement 1, 2
 Flaccid 3–80 Lower motor neuron disorder 1, 2

Notes: SDCS = Speech Disorders Classification System; PSI = Precision-Stability Index; DI = Dysarthria Index; DSI = Dysarthria Subtype Index; PM = Pause Marker.