Could SPT Result In The Overgeneralization Of Targeted Words

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Wambaugh, Martinez, McNeil, and Rogers (1999) conducted a study to replicate and expand upon the findings of the study by Wambaugh et al. (1998). They investigated response generalization and maintenance effects of SPT for trained and untrained words. Additionally, the authors attempted to determine whether SPT could result in the overgeneralization of targeted sounds to the production of untrained or previously trained phonemes (e.g., if training the production of /k/ would result in the increased substitution of /k/ for other phonemes). The participant in this study was a 62-year-old male who sustained a LCVA and presented with moderate to severe AOS, Broca’s aphasia, and a mild unilateral upper motor neuron dysarthria. The participant was …show more content…
Three phonemes that were produced incorrectly during at least 60 percent of attempted productions (/p/, /k/, and /ʃ/) were selected as target phonemes. Baseline probes were conducted to assess the stability of these phonemes in a word repetition task. Once stability was observed, the participant was trained using ten consonant-vowel (CV) and consonant-vowel-consonant (CVC) words for each target phoneme. Ten words remained untrained to assess for future generalization of production accuracy. The dependent variable of this study was the percentage of correct productions of target phonemes. The researchers adapted the original SPT hierarchy by addressing one the modifications that were originally suggested by Wambaugh et al. (1998). Modifications included requesting an increased number of elicitations for correct productions and omitting the silent juncture step entirely. Six weeks following the completion of treatment, a maintenance probe was conducted to assess whether the participants maintained the levels of accuracy that they had achieved during treatment on trained stimuli. The investigators also recorded overgeneralization errors throughout the …show more content…
There was 97 percent agreement between listeners in the determination of correct and incorrect productions. Additionally, this study could be replicated, as the authors provided specific details regarding all of the standardized assessments that were used, provided an explanation of the SPT hierarchy in the appendix, and thoroughly explained the system for calculating the occurrence of overgeneralization. A potential threat to the internal validity of this study was the short amount of time between the start of the study and the onset of the participant’s LCVA. The participant’s performance on tasks within the study might have been influenced by spontaneous recovery. Other similar studies investigating the use of SPT for AOS utilized participants that were at least one year post-onset to control for threats to internal validity. External validity is also compromised because the researchers did not assess generalization to other

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