Diagnosis

Classifying Speech Sound Disorders

Inventory of speech sounds: a list of sounds that the client can articulate within normal limits
- inconsistencies should be noted
Distribution of speech sounds: where the norm and aberrant productions occurred within the word
- pre-, post-, or intervocalic
Loss of phonemic contrasts or neutralization of specific phoneme contrasts: substituting one phoneme for one or more others
- can use minimal pairs to determine
Phonological process analysis: identifies substitution, syllable structure, and assimilatory changes

Speech Sound Disorders

Articulation disorder: consistent substitution or distortion for the target sound in spontaneous and imitative speech
- often /r/ and /s/
- 12.5% of children diagnosed with speech sound disorder
- language and phonological awareness should be tested
- least likely to show comorbidity
- may be oral mechanism difficulties
- typically mild-moderate
Phonological delay: characterized by phonological patterns that usually occur in typically developing younger children
- 57.5% of children diagnosed with a speech sound disorder
- rare to have a delay of more than 2.5 years
- primarily 3-6 year olds
- often have phonological awareness problems
- typically mild-moderate
Consistent phonological disorder: consistent use of non-developmental error patterns
- may be some delayed patterns
- 20.6% of children diagnosed with a speech sound disorder
- most children moderate-severe or severe
- often have phonological awareness difficulties
- language and phonological awareness should be examined
- focus on system-wide change to increase intelligibility
Inconsistent phonological disorder: high degree of inconsistent productions of same lexical item
- at least 40% variability on a given task
- 9.4% of children diagnosed with speech sound disorder
- most severe and pervasive speech problems
- highest involvement of additional difficulties, like language, vocabulary, and phonological awareness
- lowest oro-motor difficulty involvement
- do not respond well to normal phonological treatment
  - respond well to Core Vocabulary Intervention

Intelligibility

how much an utterance can be understood
- subjective, perceptual judgements
- factors influencing intelligibility
  - number, type, and consistency of speech sound errors
  - loss of phoneme contrasts
  - loss of contrasts in specific contexts
  - number of meaning distinctions that are not clear
  - difference between target and actual production
  - consistency of target and realization productions
  - frequency of abnormality
  - familiarity with the person's speech
  - communicative context
  - other factors (age, personality, voice and resonance quality, linguistic context, response complexity, successive judgements)

Coplan and Gleason (1988) guidelines:

2 years of age = 50% intelligible
3 years of age = 75% intelligible
4 years of age = 100% intelligible (although errors are possible)

Fudala and Stegall (2017) guidelines:

Level 6: speech errors occasionally noticed
Level 5: intelligible, although noticeably in error
Level 4: intelligible with careful listening
Level 3: intelligibility is difficult
Level 2: usually unitelligible
Level 1: unitelligible

Measures of Severity

Attempts to quantify the degree of involvement
Percentage of Consonants Correct (PCC)
- Mild = 85 - 100%
- Mild-moderate = 65 - 84.9%
- Moderate-severe= 50 - 64.9%
- Severe = <50%
Measures of Whole Words
- Portion of whole word correctness
- Portion of whole word variability
  - good for inconsistent phonological disorder

Bleile (1996) scale

1 = no disorder
2 = mild disorder
3 = moderate disorder
4 = severe disorder

Bauman-Wängler, J. A. (2020). Articulation and phonology in speech sound disorders: a clinical focus (6th ed.). Hoboken: Pearson Education.