Nancy L. Potter

Extensions to the Speech Disorders Classification System (SDCS)

This report describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). Part I describes a classification extension to the SDCS to differentiate motor speech disorders from speech delay and to differentiate among three sub-types of motor speech disorders. Part II describes the Madison Speech Assessment Protocol (MSAP), an ∼ 2-hour battery of 25 measures that includes 15 speech tests and tasks. Part III describes the Competence, Precision, and Stability Analytics (CPSA) framework, a current set of ∼ 90 perceptual- and acoustic-based indices of speech, prosody, and voice used to quantify and classify sub-types of Speech Sound Disorders (SSD). A companion paper provides reliability estimates for the perceptual and acoustic data reduction methods used in the SDCS. The agreement estimates in the companion paper support the reliability of SDCS methods and illustrate the complementary roles of perceptual and acoustic methods in diagnostic analyses of SSD of unknown origin. Examples of research using the extensions to the SDCS described in the present report include diagnostic findings for a sample of youth with motor speech disorders associated with galactosemia, and a test of the hypothesis of apraxia of speech in a group of children with autism spectrum disorders. All SDCS methods and reference databases running in the PEPPER (Programs to Examine Phonetic and Phonologic Evaluation Records) environment will be disseminated without cost when complete.

The adult galactosemic phenotype

BackgroundClassic galactosemia is an autosomal recessive disorder due to galactose-1-phosphate uridyltransferase (GALT) deficiency. Newborn screening and early treatment do not completely prevent tremor, speech deficits, and diminished IQ in both sexes and premature ovarian insufficiency (POI) in women. Data on how individuals with galactosemia fare as adults will improve our ability to predict disease progression.MethodsThirty-three adults (mean age = 32.6 ± 11.7 years; range = 18–59) with classic galactosemia, confirmed by genotype and undetectable GALT enzyme activity, were evaluated. Analyses assessed associations among age, genotype, clinical features and laboratory measures.ResultsThe sample included 17 men and 16 women. Subjects exhibited cataracts (21%), low bone density (24%), tremor (46%), ataxia (15%), dysarthria (24%), and apraxia of speech (9%). Subjects reported depression (39%) and anxiety (67%). Mean full scale IQ was 88 ± 20, (range = 55–122). All subjects followed a dairy-free diet and 75–80% reported low intake of calcium and vitamin D. Mean height, weight and body mass were within established norms. All female subjects had been diagnosed with POI. One woman and two men had had children. Logistic regression analyses revealed no associations between age, genotype or gender with IQ, tremor, ataxia, dysarthria, apraxia of speech or anxiety. Each 10- year increment of age was associated with a twofold increase in odds of depression.ConclusionsTaken together, these data do not support the hypothesis that galactosemia is a progressive neurodegenerative disease. However, greater attention to depression, anxiety, and social relationships may relieve the impact of this disorder in adults.

Correlates of language impairment in children with galactosaemia

SummaryPurposeThis study describes risk factors associated with language impairment in children with classic galactosaemia.MethodThirty-three 4–16-year-old participants with classic galactosaemia and a history of speech sound disorders completed a battery of cognitive and language measures and their parents completed a family history questionnaire.ResultsNine of the sixteen (56%) participants with typical cognitive development and 15 of the 17 (88%) with borderline-low cognitive development had language impairments. Participants with typical cognitive development more often had an expressive language disorder, whereas those with borderline-low cognitive development more often had a mixed receptive-expressive language disorder. Participants with Q188R/Q188R genotypes had increased risk for both cognitive and language impairments. The IQs of younger siblings who did not consume milk postnatally were 10–56 points higher than the IQs of their older siblings with galactosaemia who had consumed milk postnatally. However, 4 of 5 younger siblings who were lactose-restricted from birth had language impairments. Typically-reported risk factors for language disorder, including parental history of speech/learning problems and low parental education level, were not significantly associated with cognitive or language impairments in the present sample of children with galactosaemia.ConclusionsChildren with galactosaemia and speech disorders have a 4–6 times greater risk for language impairment than children with early speech disorders of unknown origin. Early dietary lactose may increase the risk for cognitive and language impairments; however, the lack of significant associations of language impairment with days of milk consumption, and other familial and educational risk factors, is consistent with prenatal causation.

Motor and Speech Disorders in Classic Galactosemia

Purpose To test the hypothesis that children with classic galactosemia and speech disorders are at risk for co-occurring strength and coordination disorders. Method This is a case-control study of 32 children (66% male) with galactosemia and neurologic speech disorders and 130 controls (50% male) ages 4-16 years. Speech was assessed using the Percentage of Consonants Correct (PCC) metric from responses to the Goldman-Fristoe Test of Articulation-2 and from a 5-min recorded speech sample, hand and tongue strength using the Iowa Oral Performance Instrument, and coordination using the Movement Assessment Battery for Children. The number of days on milk during the neonatal period was obtained by parent report. Analyses of covariance, distributions, and correlations were used to evaluate relationships among speech, strength, coordination, age, gender, and days on milk. Results Children with galactosemia had weaker hand and tongue strength and most (66%) had significant coordination disorders, primarily affecting balance and manual dexterity. Among children with galactosemia, children with more speech errors and classified as childhood apraxia of speech (n = 7) and ataxic dysarthria (n = 1), had poorer balance and manual dexterity, but not weaker hand or tongue strength, compared to the children with fewer speech errors. The number of days on milk during the neonatal period was associated with more speech errors in males but not in females. Conclusion Children with galactosemia have a high prevalence of co-occurring speech, coordination, and strength disorders, which may be evidence of a common underlying etiology, likely associated with diffuse cerebellar damage, rather than distinct disorders.

Perceptual and acoustic reliability estimates for the Speech Disorders Classification System (SDCS)

A companion paper describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). The SDCS uses perceptual and acoustic data reduction methods to obtain information on a speakers speech, prosody, and voice. The present paper provides reliability estimates for the two perceptual methods (narrow phonetic transcription; prosody-voice coding) and the acoustic analysis methods the SDCS uses to describe and classify a speakers speech competence, precision, and stability. Speech samples from 10 speakers, five with significant motor speech disorder and five with typical speech, were re-measured to estimate intra-judge and inter-judge agreement for the perceptual and acoustic methods. Each of the speakers completed five speech tasks (total = 50 datasets), ranging in articulatory difficulty for the speakers, with consequences for the difficulty level of data reduction. Point-to-point percentage of agreement findings for the two perceptual methods were as high or higher than reported in literature reviews and from previous studies conducted within the laboratory. Percentage of agreement findings for the acoustics tasks of segmenting phonemes, editing fundamental frequency tracks, and estimating formants ranged from values in the mid 70% to 100%, with most estimates in the mid 80% to mid 90% range. Findings are interpreted as support for the perceptual and acoustic methods used in the SDCS to describe and classify speakers with speech sound disorders.

The Use of Simulation in Training Graduate Students to Perform Transnasal Endoscopy

A challenge facing the field of speech-language pathology is how to equip students at the university level with the transnasal endoscopy skills needed to perform fiberoptic endoscopic evaluation of swallowing (FEES). The use of simulation has the potential to allow students to gain transnasal endoscopy experience with repetitive practice without compromising patients. The present study examined the effects of two different forms of simulation training on multiple transnasal endoscopic passes on healthy volunteers by graduate student clinicians as measured by procedure duration and confidence ratings. Eighteen speech-language pathology graduate student clinicians were randomly assigned to groups that utilized either a human patient simulator (HPS) or a non-lifelike simulator for transnasal endoscopy training. Using a flexible nasal endoscope, each clinician performed seven training passes on a simulator and one pass on two different volunteers. Each volunteer was endoscoped two times, once by a clinician trained using a HPS and once by a clinician trained using a non-lifelike simulator. There was no difference in pass times on volunteers between clinicians trained using the HPS and clinicians trained on the non-lifelike simulator. Both training groups were faster and more confident on the second endoscopy on a volunteer than on the first.

Voice disorders in children with classic galactosemia

Children with classic galactosemia are at risk for motor speech disorders resulting from disruptions in motor planning and programming (childhood apraxia of speech or CAS) or motor execution (dysarthria). In the present study of 33 children with classic galactosemia, 21% were diagnosed with CAS, 3% with ataxic dysarthria, and 3% with mixed CAS-dysarthria. Voice disorders due to laryngeal insufficiency were common in children with dysarthria and co-occurred with CAS. Most (58%) of the children with classic galactosemia had decreased respiratory-phonatory support for speech, and 33% had disturbed vocal quality that was indicative of cerebellar dysfunction. Three children, two diagnosed with CAS and one not diagnosed with a motor speech disorder, had vocal tremors. Treatment of voice dysfunction in neurogenic speech disorders is discussed.

Oral and manual force control in preschool-aged children: is there evidence for common control?

The authors examined and compared the development of oral and manual force control in preschool-aged children. In all, 50 typically developing children (aged 3-5 years) performed maximal strength tasks and submaximal visually guided tasks using tongue elevation, power, and precision grips. Dependent measures included strength, rate of force rise, initial force overshoot, force variability, and rate of force release. The authors performed age- and performance-related analyses. Results revealed similar changes for tongue, fingers, and hands across age- and performance-related measures for strength, initial force overshoot, and rate of force release. There were no significant changes in rate of force rise with increasing age. Force variability measures showed effector-specific changes with decreases across age- and performance-related measures for the hands and fingers but not for the tongue. Changes common across effector systems likely reflect biological development coupled with cognitive-strategic development. Effector-specific changes in force variability likely reflect experience gained through functional tasks influencing biological and cognitive-strategic development. Lack of change in force variability of the tongue suggests that fine control of the tongue is activity specific; thus, nonfunctional tasks are not likely to be sensitive to experience-related biological development.

Effects of strength training on neuromuscular facial rehabilitation.

Objective: Physical trauma is the third leading cause of facial nerve damage, which can disrupt communication, social interaction and emotional expression. The objective of this report was to investigate the effects of facial muscle exercise as a stand-alone treatment in a young adult with unilateral facial nerve damage 13-years post-onset. Method: This single case study examines the long-term results of a 7-week intensive facial exercise programme followed by a 16-week moderate facial exercise programme. Results: Intensive exercise increased facial strength and upper lip elevation on the affected side and upper and lower lip strength on the affected and non-affected sides. With subsequent moderate exercise followed by 24 weeks of rest, strength was maintained but not increased. Conclusion: With intensive facial exercise, muscle weakness resulting from facial nerve damage sustained during childhood can be improved years after injury.

Developmental Outcomes of School-Age Children with Duarte Galactosemia: A Pilot Study

Duarte galactosemia (DG) is a mild allelic variant of classic galactosemia that results from partial impairment of galactose-1P uridylyltransferase (GALT). Although infants with DG are detected by newborn screening in some US states at close to 1/4,000 live births, most are discharged from follow-up very early in life and there is no consensus on whether these children are at increased risk for any of the long-term developmental delays seen in classic galactosemia. There is also no consensus on whether infants with DG benefit from dietary restriction of galactose. Reflecting the current uncertainty, some states choose to identify infants with DG by newborn screening and others do not. As a first step toward characterizing the developmental outcomes of school-age children with DG, we conducted a pilot study, testing 10 children with DG and 5 unaffected siblings from the same group of families. All children tested were between 6 and 11 years old. We used standardized direct assessments and parent-response surveys to collect information regarding cognition, communication, socio-emotional, adaptive behavior, and physical development for each child. Despite the small sample size, our data demonstrated some notable differences between cases and controls in socio-emotional development, in delayed recall, and in auditory processing speed. These results confirm that direct assessment of school-age children with DG can detect subtle but potentially problematic developmental deficits, and underscore the need for a larger study which has sufficient power to evaluate these outcomes while controlling for potentially confounding factors.