Mechanisms and neuroanatomy of response selection in tool and non-tool action tasks: Evidence from left-hemisphere stroke

The ability to select between potential actions is central to the complex process of tool use. After left hemisphere stroke, individuals with limb apraxia make more hand action errors when gesturing the use of tools with conflicting hand actions for grasping-to-move and use (e.g., screwdriver) relative to tools that are grasped-to-move and used with the same hand action (e.g., hammer). Prior research indicates that this grasp-use interference effect is driven by abnormalities in the competitive action selection process. The goal of this project was to determine whether common mechanisms and neural substrates support the competitive selection of task-appropriate responses in both tool and non-tool domains. If so, the grasp-use interference effect in a tool use gesturing task should be correlated with response interference effects in the classic Eriksen flanker and Simon tasks, and at least partly overlapping neural regions should subserve the 3 tasks. Sixty-four left hemisphere stroke survivors (33 with apraxia) participated in the tool- and non-tool interference tasks and underwent T1 anatomical MRI. There were robust grasp-use interference effects (grasp-use conflict test) and response interference effects (Eriksen flanker and Simon tasks), but these effects were not correlated. Lesion-symptom mapping analyses showed that lesions to the left inferior parietal lobule, ventral premotor cortex, and insula were associated with grasp-use interference. Lesions to the left inferior parietal lobule, postcentral gyrus, insula, caudate, and putamen were associated with response interference in the Eriksen flanker task. Lesions to the left caudate and putamen were also associated with response interference in the Simon task. Our results suggest that the selection of hand posture for tool use is mediated by distinct cognitive mechanisms and partly distinct neuroanatomic substrates from those mapping a stimulus to an appropriate motor response in non-tool domains.

Progressive aphasia, apraxia of speech and agraphia in corticobasal degeneration: A 12-case series clinical and neuropsychological descriptive study

BACKGROUND

Despite initial underreporting of language dysfunctions in corticobasal syndrome (CBS), aphasia is now recognized as a frequent feature of this disease. Aphasia in CBS seems clinically overlying to a non-fluent/agrammatic primary progressive aphasia (nfaPPA), which is also a clinical phenotype associated with corticobasal degeneration (CBD) pathology. However, the clinical features of aphasia in CBS still remain poorly delineated, resulting in misjudgements in the differential diagnosis from a PPA presentation of the disease.

AIMS

To investigate the language disorders of this syndrome, also through a systematic examination of recoding skills (reading, written spelling and repetition) and articulatory disturbances, which have been rarely examined in previous studies.

METHODS & PROCEDURES

We present a clinical and neuropsychological descriptive study of the language impairments in a case series of 12 aphasic patients with a clinical diagnosis of CBS. Language assessment was conducted by means of the Esame NeuroPsicologico dell'Afasia, a comprehensive Italian battery for language functions, the Token Test, and the Apraxia of Speech Rating Scale.

OUTCOMES & RESULTS

The language profile of the patients showed a severe expressive language disorder, characterized by non-fluent speech, apraxia of speech (AoS) with predominant stuttering-like dysfluencies, spatial/apraxic agraphia, lack of word-finding and defective sentence repetition. Severe limb apraxia, visual-spatial deficit and alien hand syndrome were also present. Neuroimaging showed bilateral left asymmetric atrophies and hypometabolism in the frontal premotor, parietal posterior and temporal areas.

CONCLUSIONS & IMPLICATIONS

These findings suggest that aphasia in CBS might present as a 'mixed PPA', instead of an nfaPPA as previously stated, showing a combination of features of the nfa and logopenic variants of the PPA, associated with AoS, stuttering and agraphia, which might be additional important cognitive markers for the clinical diagnosis of CBS and discriminating features of an nfaPPA presentation of a CBD. These results might also suggest specific intervention areas in the rehabilitation of patients with CBS. What this paper adds What is already known on the subject Language disorders in CBS patients usually present clinically overlying to an nfaPPA, which is also a clinical phenotype associated with CBD pathology, according to recent diagnostic criteria. However, the clinical features of aphasia in CBS still remain poorly delineated, and this raises difficulties and misjudgements for clinicians in the differential diagnosis from a PPA presentation of the disease. What this paper adds to existing knowledge This study shows that the language profile of our CBS patients was characterized by severe expressive language disorders, with non-fluent speech, apraxia of speech (AoS) with predominant stuttering-like dysfluencies, spatial/apraxic agraphia, lack of word-finding, and defective sentence repetition. These findings suggest that aphasia in CBS might present as a 'mixed PPA', rather than an nfaPPA as previously stated, showing a combination of features of the nfa and logopenic variants of the PPA associated with AoS, stuttering and agraphia. What are the potential or actual clinical implications of this work? These results suggest that AoS, stuttering and agraphia might be important additional cognitive markers for the clinical diagnosis of CBS, and discriminating features of an nfaPPA presentation of a CBD. The language disorders exhibited in the present study might also support speech and language therapists in targeting specific intervention areas in the rehabilitation of patients with CBS.

Perceptual Characteristics of Consonant Production in Apraxia of Speech and Aphasia

Purpose This retrospective analysis examined group differences in error rate across 4 contextual variables (clusters vs. singletons, syllable position, number of syllables, and articulatory phonetic features) in adults with apraxia of speech (AOS) and adults with aphasia only. Group differences in the distribution of error type across contextual variables were also examined. Method Ten individuals with acquired AOS and aphasia and 11 individuals with aphasia participated in this study. In the context of a 2-group experimental design, the influence of 4 contextual variables on error rate and error type distribution was examined via repetition of 29 multisyllabic words. Error rates were analyzed using Bayesian methods, whereas distribution of error type was examined via descriptive statistics. Results There were 4 findings of robust differences between the 2 groups. These differences were found for syllable position, number of syllables, manner of articulation, and voicing. Group differences were less robust for clusters versus singletons and place of articulation. Results of error type distribution show a high proportion of distortion and substitution errors in speakers with AOS and a high proportion of substitution and omission errors in speakers with aphasia. Conclusion Findings add to the continued effort to improve the understanding and assessment of AOS and aphasia. Several contextual variables more consistently influenced breakdown in participants with AOS compared to participants with aphasia and should be considered during the diagnostic process. Supplemental Material https://doi.org/10.23641/asha.9701690.

Reading Outcomes for Individuals With Histories of Suspected Childhood Apraxia of Speech

Purpose The primary aims of this study were to examine the speech-language correlates of decoding difficulties in children with histories of suspected childhood apraxia of speech (sCAS) and to identify predictors of low-proficiency reading levels. Method Participants were school-age children and adolescents, 7-18 years of age, diagnosed with sCAS (n = 40) or speech sound disorder but no sCAS (SSD-no sCAS; n = 119). The sCAS and SSD-no sCAS reading groups were compared on measures of performance IQ, oral language, phonological awareness, rapid automatic naming, diadochokinetic rates, single word articulation, and multisyllable and nonsense word repetition. Logistic regression analyses were employed to identify predictors of low-proficiency reading in the sCAS and SSD-no sCAS groups. Results Sixty-five percent of the participants with sCAS compared to 24% of those with SSD-no sCAS were classified as low-proficiency readers based on nonsense and single word decoding. Analysis failed to reveal significant differences in reading, oral language, or phonological awareness between low-proficiency readers with sCAS and low-proficiency readers with SSD-no sCAS. Oral language and phonological awareness skills were the best predictors of reading level for all participants, followed by performance on multisyllabic word repetition and diadochokinetic rate. Conclusions The language and phonological awareness deficits of children with sCAS are related to their risks for reading failure. To a lesser degree, motor speech deficits and speech sound production also increase risks for reading difficulties. The findings justify early intervention for this subset of children.

Reduced competition between tool action neighbors in left hemisphere stroke

When pantomiming the use of tools, patients with limb apraxia after left hemisphere stroke (LCVA) produce more spatiotemporal hand action errors with tools associated with conflicting actions for use versus grasp-to-pick-up (e.g., corkscrew) than tools having a single action for both use and grasp (e.g., hammer). There are two possible accounts for this pattern of results. Reduced performance with 'conflict' tools may simply reflect weakened automaticity of use action activation, which is evident only when the use and grasp actions are not redundant. Alternatively, poor use performance may reflect a reduced ability of appropriate tool use actions to compete with task-inappropriate action representations. To address this issue, we developed a Stroop-like experiment in which 21 LCVA and 8 neurotypical participants performed pantomime actions in blocks containing two tools that were similar ("neighbors") in terms of hand action or function, or were unrelated on either dimension. In a congruent condition, they pantomimed the use action associated with the visually presented tool, whereas in an incongruent condition, they pantomimed the use action for the other tool in the block. Relative to controls and other task conditions, LCVA participants showed reductions in hand action errors in incongruent relative to congruent action trials; furthermore, the degree of reduction in this incongruence effect was related to the participants' susceptibility to grasp-on-use conflict in a separate test of pantomime to the sight of tools. Support vector regression lesion-symptom mapping analyses identified the left inferior frontal gyrus, supramarginal gyrus, and superior longitudinal fasciculus as core neuroanatomical sites associated with abnormal performance. Collectively, the results indicate that weakened activation of tool use actions in limb apraxia gives rise to reduced ability of these actions to compete for task-appropriate selection when competition arises within single tools (grasp-on-use conflict) as well as between two tools (reduced neighborhood effects).

Reliability and stability of the metrical stress effect on segmental production accuracy in persons with apraxia of speech

BACKGROUND

Acquired apraxia of speech (AOS) involves speech-production deficits on both the segmental and suprasegmental levels. Recent research has identified a non-linear interaction between the metrical structure of bisyllabic words and word-production accuracy in German speakers with AOS, with trochaic words (strong-weak stress) being resistant to errors compared with iambic words (weak-strong).

AIMS

To replicate previous findings in English speakers with AOS, to measure the test-retest reliability of the effect, and to examine the potential impact of different methods of word scoring.

METHODS & PROCEDURES

Speech samples were collected from 27 speakers with AOS and aphasia. Participants were at least 12 months post-stroke or penetrating brain injury, and represented a large range of AOS and aphasia severities. Productions were elicited via verbal model. Sampling was conducted on three separate occasions: the initial data-collection session and then repeated samplings at 1- and 4-week intervals. Bisyllabic words with a CVCVC segmental structure were selected. The list was divided into sublists representing differing lexical stress patterns: A list of 42 trochees, and one of 37 iambs. All speech samples were phonetically transcribed and then aligned with canonical transcriptions via an edit distance algorithm that followed transcription alignment principles. Phonetic-level errors (distortions) were penalized less severely than phonemic-level errors. Per cent consonants correct and whole-word accuracy were also examined. Trochee and iamb lists were analysed separately.

OUTCOMES & RESULTS

Paired samples t-tests indicated that the modified edit distance was significantly lower for the trochee lists than for the iamb lists. There was a lack of a significant effect of time on the absolute difference between modified edit distance for both lists. Intraclass coefficients suggested the list and procedures used are appropriate as an outcome measure for group research.

CONCLUSIONS & IMPLICATIONS

The results suggest that in English, as in German, the trochaic structure is more resistant to segmental errors in persons with AOS and aphasia, providing replication of the findings of Aichert et al. in 2016. Further, this effect is stable over repeated sampling occasions. Implications for clinical management of AOS include possible ways to scaffold item difficulty and potentially improve stimulus generalization.

A Case Study Using a Multimodal Approach to Melodic Intonation Therapy

PURPOSE

The purpose of this study was to assess the efficacy. of increasing spontaneous expressive language using a modified melodic intonation therapy (MIT) approach with a male participant diagnosed with acquired aphasia and apraxia who was 10 years post onset.

METHOD

A therapeutic protocol consisting of vocal and linguistic tasks was administered. The participant attended two 50-min individual sessions and a 4-hr/week socialization program for three 12-week semesters. Measures of speech and language were administered before intervention and at the completion of each of the 3 semesters.

RESULTS

At the completion of the study, the participant demonstrated reduced apraxia of speech as measured by The Apraxia Battery for Adults, Second Edition (Dabul, 2000). He also showed improvements in auditory comprehension skills as measured on the Boston Diagnostic Aphasia Evaluation (Goodglass, Kaplan, & Barresi, 2000). His spontaneous utterances were characterized by an increased number of complete sentences and questions. Several language parameters including mean length of utterance, total number of spontaneous (untrained) utterances, and number of different words spoken were also improved as revealed through language analysis.

CONCLUSIONS

Integration of melodic intonation therapy through the addition of musical elements may result in improved speech and expressive language skills when administered over a 9-month period in conjunction with a group socialization program.

Quantitative Analysis of Agrammatism in Agrammatic Primary Progressive Aphasia and Dominant Apraxia of Speech

PURPOSE

The aims of the study were to assess and compare grammatical deficits in written and spoken language production in subjects with agrammatic primary progressive aphasia (agPPA) and in subjects with agrammatism in the context of dominant apraxia of speech (DAOS) and to investigate neuroanatomical correlates.

METHOD

Eight agPPA and 21 DAOS subjects performed the picture description task of the Western Aphasia Battery (WAB) both in writing and orally. Responses were transcribed and coded for linguistic analysis. agPPA and DAOS were compared to 13 subjects with primary progressive apraxia of speech (PPAOS) who did not have agrammatism. Spearman correlations were performed between the written and spoken variables. Patterns of atrophy in each group were compared, and relationships between the different linguistic measures and integrity of Broca's area were assessed.

RESULTS

agPPA and DAOS both showed lower mean length of utterance, fewer grammatical utterances, more nonutterances, more syntactic and semantic errors, and fewer complex utterances than PPAOS in writing and speech, as well as fewer correct verbs and nouns in speech. Only verb ratio and proportion of grammatical utterances correlated between modalities. agPPA and DAOS both showed greater involvement of Broca's area than PPAOS, and atrophy of Broca's area correlated with proportion of grammatical and ungrammatical utterances and semantic errors in writing and speech.

CONCLUSIONS

agPPA and DAOS subjects showed similar patterns of agrammatism, although subjects performed differently when speaking versus writing. Integrity of Broca's area correlates with agrammatism.

The Relationship Between Speech, Language, and Phonological Awareness in Preschool-Age Children With Developmental Disabilities

PURPOSE

A number of intrinsic factors, including expressive speech skills, have been suggested to place children with developmental disabilities at risk for limited development of reading skills. This study examines the relationship between these factors, speech ability, and children's phonological awareness skills.

METHOD

A nonexperimental study design was used to examine the relationship between intrinsic skills of speech, language, print, and letter-sound knowledge to phonological awareness in 42 children with developmental disabilities between the ages of 48 and 69 months. Hierarchical multiple regression was done to determine if speech ability accounted for a unique amount of variance in phonological awareness skill beyond what would be expected by developmental skills inclusive of receptive language and print and letter-sound knowledge.

RESULTS

A range of skill in all areas of direct assessment was found. Children with limited speech were found to have emerging skills in print knowledge, letter-sound knowledge, and phonological awareness. Speech ability did not predict a significant amount of variance in phonological awareness beyond what would be expected by developmental skills of receptive language and print and letter-sound knowledge.

CONCLUSION

Children with limited speech ability were found to have receptive language and letter-sound knowledge that supported the development of phonological awareness skills. This study provides implications for practitioners and researchers concerning the factors related to early reading development in children with limited speech ability and developmental disabilities.

Poor Speech Perception Is Not a Core Deficit of Childhood Apraxia of Speech: Preliminary Findings

PURPOSE

Childhood apraxia of speech (CAS) is hypothesized to arise from deficits in speech motor planning and programming, but the influence of abnormal speech perception in CAS on these processes is debated. This study examined speech perception abilities among children with CAS with and without language impairment compared to those with language impairment, speech delay, and typically developing peers.

METHOD

Speech perception was measured by discrimination of synthesized speech syllable continua that varied in frequency (/dɑ/-/ɡɑ/). Groups were classified by performance on speech and language assessments and compared on syllable discrimination thresholds. Within-group variability was also evaluated.

RESULTS

Children with CAS without language impairment did not significantly differ in syllable discrimination compared to typically developing peers. In contrast, those with CAS and language impairment showed significantly poorer syllable discrimination abilities compared to children with CAS only and typically developing peers. Children with speech delay and language impairment also showed significantly poorer discrimination abilities, with appreciable within-group variability.

CONCLUSIONS

These findings suggest that speech perception deficits are not a core feature of CAS but rather occur with co-occurring language impairment in a subset of children with CAS. This study establishes the significance of accounting for language ability in children with CAS.

SUPPLEMENTAL MATERIALS

https://doi.org/10.23641/asha.5848056.

Language Changes Following Combined Aphasia and Apraxia of Speech Treatment

PURPOSE

Combined Aphasia and Apraxia of Speech Treatment (CAAST) is a newly developed treatment shown to increase production of accurate content in narrative discourse for persons with aphasia and apraxia of speech. The purpose of this post hoc study was to further describe lexical and morphosyntactic changes associated with changes in content production.

METHOD

Existing probe data from 8 persons with aphasia who had completed CAAST were used to complete analyses of morphosyntactic production, lexical diversity, and novelty of content. Language analyses were completed using discourse samples obtained at numerous pretreatment and posttreatment intervals.

RESULTS

All participants demonstrated gains in morphosyntactic language output for treated items, which extended to untreated sets for 7 participants. All 8 increased in production of novel content. Lexical diversity increases were evident for most participants. Although there were some similarities in language changes, there was substantial variability across response profiles.

CONCLUSION

CAAST, previously associated with positive treatment effects for production of accurate content, also appears to facilitate acquisition and generalization of morphosyntactic complexity, lexical diversity, and novelty of content for individuals with nonfluent aphasia. Further investigation is needed to determine causality and appropriate clinical application.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.5912530.

Effects of Treatment Intensity on Outcomes in Acquired Apraxia of Speech

PURPOSE

This investigation was designed to examine the effects of treatment intensity (i.e., dose frequency) on the outcomes of Sound Production Treatment (SPT) for acquired apraxia of speech.

METHOD

Five men with chronic apraxia of speech and aphasia received both intense SPT (3 hr per day/3 days per week) and nonintense/traditional SPT (SPT-T; 1 hr per day/3 days per week) in the context of single-case experimental designs. Each treatment was applied separately to a designated set of experimental words with 1 treatment applied at a time. Twenty-seven treatment sessions were conducted with each phase of treatment. Accuracy of articulation of target sounds within treated and untreated experimental words was measured during the course of the investigation.

RESULTS

All participants demonstrated improved articulation with both treatment intensities. Better maintenance of gains for treated items was found with SPT-T for 2 participants as measured at an 8-week posttreatment retention probe. Superior maintenance of increased accuracy of production of untreated items was also observed with SPT-T for all participants.

CONCLUSION

A less intense (distributed) application of SPT facilitated better maintenance of improved articulatory accuracy for untreated items, and in some cases treated items, than intense SPT.

SUPPLEMENTAL MATERIALS

https://doi.org/10.23641/asha.5734053.

Error Consistency in Acquired Apraxia of Speech With Aphasia: Effects of the Analysis Unit

PURPOSE

Diagnostic recommendations for acquired apraxia of speech (AOS) have been contradictory concerning whether speech sound errors are consistent or variable. Studies have reported divergent findings that, on face value, could argue either for or against error consistency as a diagnostic criterion. The purpose of this study was to explain discrepancies in error consistency results based on the unit of analysis (segment, syllable, or word) to help determine which diagnostic recommendation is most appropriate.

METHOD

We analyzed speech samples from 14 left-hemisphere stroke survivors with clinical diagnoses of AOS and aphasia. Each participant produced 3 multisyllabic words 5 times in succession. Broad phonetic transcriptions of these productions were coded for consistency of error location and type using the word and its constituent syllables and sound segments as units of analysis.

RESULTS

Consistency of error type varied systematically with the unit of analysis, showing progressively greater consistency as the analysis unit changed from the word to the syllable and then to the sound segment. Consistency of error location varied considerably across participants and correlated positively with error frequency.

CONCLUSIONS

Low to moderate consistency of error type at the word level confirms original diagnostic accounts of speech output and sound errors in AOS as variable in form. Moderate to high error type consistency at the syllable and sound levels indicate that phonetic error patterns are present. The results are complementary and logically compatible with each other and with the literature.

Finger tapping and verbal fluency post-tap test improvement in INPH: its value in differential diagnosis and shunt-treatment outcomes prognosis

BACKGROUND

Idiopathic normal pressure hydrocephalus (INPH) diagnosis is challenging as it can be mimicked by other neurological conditions, such as neurodegenerative dementia and motor syndromes. Additionally, outcomes after lumbar puncture (LP) tap test and shunt treatment may vary due to the lack of a common protocol in INPH assessment. The present study aimed to assess whether a post-LP test amelioration of frontal cognitive dysfunctions, characterizing this syndrome, can differentiate INPH from similar neurological conditions and whether this improvement can predict INPH post-shunt outcomes.

METHOD

Seventy-one consecutive patients referred for INPH suspicion and LP testing, were enrolled. According to the consensus guidelines criteria, 29 patients were diagnosed as INPH and 42 were assigned an alternative diagnosis (INPH-like group) after reviewing clinical, neuropsychological and imaging data, and before LP results. A comprehensive neuropsychological assessment for frontal executive, upper extremity fine motor functions, aphasias, apraxias, agnosias and gait evaluation were administered at baseline. Executive, fine motor functions and gait were re-examined post-LP test in all patients and post-shunt placement in INPH patients.

RESULTS

Of the INPH patients, 86.2% showed cognitive amelioration in the post-LP test; in addition, all but one (97%) presented with neurocognitive and gait improvement post-shunt. Verbal phonological fluency and finger tapping task post-LP improvement predicted positive clinical outcome post-shunt. None of the INPH-like group presented with neurocognitive improvement post-LP.

CONCLUSIONS

Post-LP amelioration of verbal fluency and finger tapping deficits can differentiate INPH from similar disorders and predict positive post-shunt clinical outcome in INPH. This becomes of great importance when gait assessment is difficult to perform in clinical practice.

Phonological working memory and FOXP2

The discovery and description of the affected members of the KE family (aKE) initiated research on how genes enable the unique human trait of speech and language. Many aspects of this genetic influence on speech-related cognitive mechanisms are still elusive, e.g. if and how cognitive processes not directly involved in speech production are affected. In the current study we investigated the effect of the FOXP2 mutation on Working Memory (WM). Half the members of the multigenerational KE family have an inherited speech-language disorder, characterised as a verbal and orofacial dyspraxia caused by a mutation of the FOXP2 gene. The core phenotype of the affected KE members (aKE) is a deficiency in repeating words, especially complex non-words, and in coordinating oromotor sequences generally. Execution of oromotor sequences and repetition of phonological sequences both require WM, but to date the aKE's memory ability in this domain has not been examined in detail. To do so we used a test series based on the Baddeley and Hitch WM model, which posits that the central executive (CE), important for planning and manipulating information, works in conjunction with two modality-specific components: The phonological loop (PL), specialized for processing speech-based information; and the visuospatial sketchpad (VSSP), dedicated to processing visual and spatial information. We compared WM performance related to CE, PL, and VSSP function in five aKE and 15 healthy controls (including three unaffected members of the KE family who do not have the FOXP2 mutation). The aKE scored significantly below this control group on the PL component, but not on the VSSP or CE components. Further, the aKE were impaired relative to the controls not only in motor (i.e. articulatory) output but also on the recognition-based PL subtest (word-list matching), which does not require speech production. These results suggest that the aKE's impaired phonological WM may be due to a defect in subvocal rehearsal of speech-based material, and that this defect may be due in turn to compromised speech-based representations.

The Effect of Hand Gesture Cues Within the Treatment of /r/ for a College-Aged Adult With Persisting Childhood Apraxia of Speech

PURPOSE

Despite the widespread use of hand movements as visual and kinesthetic cues to facilitate accurate speech produced by individuals with speech sound disorders (SSDs), no experimental investigation of gestural cues that mimic that spatiotemporal parameters of speech sounds (e.g., holding fingers and thumb together and "popping" them to cue /p/) currently exists. The purpose of this study was to examine the effectiveness of manual mimicry cues within a multisensory intervention of persisting childhood apraxia of speech (CAS).

METHOD

A single-subject ABAB withdrawal design was implemented to assess the accuracy of vowel + /r/ combinations produced by a 21-year-old woman with persisting CAS. The effect of manual mimicry gestures paired with multisensory therapy consisting of verbal instructions and visual modeling was assessed via clinician and naïve listener ratings of target sound accuracy.

RESULTS

According to the perceptual ratings of the treating clinician and 28 naïve listeners, the participant demonstrated improved speech sound accuracy as a function of the manual mimicry/multisensory therapy.

CONCLUSIONS

These data offer preliminary support for the incorporation of gestural cues in therapy for CAS and other SSDs. The need for continued research on the interaction of speech and manual movements for individuals with SSDs is discussed.

Variable Practice to Enhance Speech Learning in Ultrasound Biofeedback Treatment for Childhood Apraxia of Speech: A Single Case Experimental Study

PURPOSE

The purpose of this study was to evaluate the role of practice variability, through prosodic variation during speech sound training, in biofeedback treatment for children with childhood apraxia of speech. It was hypothesized that variable practice would facilitate speech sound learning.

METHOD

Six children ages 8-16 years with persisting speech sound errors due to childhood apraxia of speech participated in a single-subject experimental design. For each participant, 2 speech sound targets were treated with ultrasound visual feedback training: one with prosodic variation (i.e., practicing sound targets in words and phrases spoken fast, slow, loud, as a question, command, and declarative), and one without prosodic variation. Each target was treated for half of the 1-hr session for 14 treatment sessions.

RESULTS

As measured by standardized effect sizes, all participants showed greater change on generalization probes for sound targets treated under the prosodic variation condition with mean effect sizes (d2) of 14.5 for targets treated with prosodic variation and 8.3 for targets treated without prosodic variation. The average increase in generalization scores was 38% in the prosodic variation condition compared to 31% without.

CONCLUSIONS

Ultrasound visual feedback may facilitate speech sound learning and learning may be enhanced by treating speech sounds with explicit prosodic variation.

SUPPLEMENTAL MATERIALS

https://doi.org/10.23641/asha.5150119.

Perceptually Salient Sound Distortions and Apraxia of Speech: A Performance Continuum

PURPOSE

We sought to characterize articulatory distortions in apraxia of speech and aphasia with phonemic paraphasia and to evaluate the diagnostic validity of error frequency of distortion and distorted substitution in differentiating between these disorders.

METHOD

Study participants were 66 people with speech sound production difficulties after left-hemisphere stroke or trauma. They were divided into 2 groups on the basis of word syllable duration, which served as an external criterion for speaking rate in multisyllabic words and an index of likely speech diagnosis. Narrow phonetic transcriptions were completed for audio-recorded clinical motor speech evaluations, using 29 diacritic marks.

RESULTS

Partial voicing and altered vowel tongue placement were common in both groups, and changes in consonant manner and place were also observed. The group with longer word syllable duration produced significantly more distortion and distorted-substitution errors than did the group with shorter word syllable duration, but variations were distributed on a performance continuum that overlapped substantially between groups.

CONCLUSIONS

Segment distortions in focal left-hemisphere lesions can be captured with a customized set of diacritic marks. Frequencies of distortions and distorted substitutions are valid diagnostic criteria for apraxia of speech, but further development of quantitative criteria and dynamic performance profiles is necessary for clinical utility.

Quantification and Systematic Characterization of Stuttering-Like Disfluencies in Acquired Apraxia of Speech

PURPOSE

The purpose of this article is to quantify and describe stuttering-like disfluencies in speakers with acquired apraxia of speech (AOS), utilizing the Lidcombe Behavioural Data Language (LBDL). Additional purposes include measuring test-retest reliability and examining the effect of speech sample type on disfluency rates.

METHOD

Two types of speech samples were elicited from 20 persons with AOS and aphasia: repetition of mono- and multisyllabic words from a protocol for assessing AOS (Duffy, 2013), and connected speech tasks (Nicholas & Brookshire, 1993). Sampling was repeated at 1 and 4 weeks following initial sampling. Stuttering-like disfluencies were coded using the LBDL, which is a taxonomy that focuses on motoric aspects of stuttering.

RESULTS

Disfluency rates ranged from 0% to 13.1% for the connected speech task and from 0% to 17% for the word repetition task. There was no significant effect of speech sampling time on disfluency rate in the connected speech task, but there was a significant effect of time for the word repetition task. There was no significant effect of speech sample type.

CONCLUSIONS

Speakers demonstrated both major types of stuttering-like disfluencies as categorized by the LBDL (fixed postures and repeated movements). Connected speech samples yielded more reliable tallies over repeated measurements. Suggestions are made for modifying the LBDL for use in AOS in order to further add to systematic descriptions of motoric disfluencies in this disorder.

Acquired Apraxia of Speech: The Relationship Between Awareness of Errors in Word Productions and Treatment Outcomes

PURPOSE

Awareness of errors has been considered a clinical feature of acquired apraxia of speech (AOS). However, there is limited research examining error awareness in speakers with AOS. The purpose of this investigation was to examine awareness of errors and explore the relationship between awareness of errors and treatment outcomes in speakers with AOS.

METHOD

Twenty speakers with AOS and aphasia produced mono- and multisyllabic words in a repetition task. Following each production, speakers were asked to judge the accuracy of their production (i.e., correct or incorrect). Then, speakers received Sound Production Treatment.

RESULTS

Judgment accuracy of productions for the group ranged from 20% to 96%. There was a weak relationship between judgment accuracy and probe performance at posttreatment (r = .47) and a moderate relationship between judgment accuracy and probe performance at follow-up (r = .53).

CONCLUSION

Findings indicate that speakers with AOS varied in their ability to judge the accuracy of their productions. For some speakers, the ability to judge the accuracy of their productions did not coincide with their production accuracy of treatment stimuli at posttreatment and at follow-up. Further research is needed to explore the relationship between error awareness and treatment outcomes.

The Nature of Error Consistency in Individuals With Acquired Apraxia of Speech and Aphasia

PURPOSE

The primary characteristics used to define acquired apraxia of speech (AOS) have evolved to better reflect a disorder of motor planning/programming. However, there is debate regarding the feature of relatively consistent error location and type.

METHOD

Ten individuals with acquired AOS and aphasia and 11 individuals with aphasia without AOS participated in this study. In the context of a 2-group experimental design, error consistency was examined via 5 repetitions of 30 multisyllabic words. The influence of error rate, severity of impairment, and stimulus presentation condition (blocked vs. random) on error consistency was also explored, as well as between-groups differences in the types of errors produced.

RESULTS

Groups performed similarly on consistency of error location; however, adults with AOS demonstrated greater variability of error type in a blocked presentation condition only. Stimulus presentation condition, error rate, and severity of impairment did not influence error consistency in either group. Groups differed in the production of phonetic errors (e.g., sound distortions) but not phonemic errors.

CONCLUSIONS

Overall, findings do not support relatively consistent errors as a differentiating characteristic of AOS.

Student life - Role of neurodiverse nurses

Students and practitioners who are 'neurodiverse' - encompassing people who are dyslexic and dyspraxic - make a positive contribution to patient care, and should be celebrated.

Auditory Masking Effects on Speech Fluency in Apraxia of Speech and Aphasia: Comparison to Altered Auditory Feedback

PURPOSE

To study the effects of masked auditory feedback (MAF) on speech fluency in adults with aphasia and/or apraxia of speech (APH/AOS). We hypothesized that adults with AOS would increase speech fluency when speaking with noise. Altered auditory feedback (AAF; i.e., delayed/frequency-shifted feedback) was included as a control condition not expected to improve speech fluency.

METHOD

Ten participants with APH/AOS and 10 neurologically healthy (NH) participants were studied under both feedback conditions. To allow examination of individual responses, we used an ABACA design. Effects were examined on syllable rate, disfluency duration, and vocal intensity.

RESULTS

Seven of 10 APH/AOS participants increased fluency with masking by increasing rate, decreasing disfluency duration, or both. In contrast, none of the NH participants increased speaking rate with MAF. In the AAF condition, only 1 APH/AOS participant increased fluency. Four APH/AOS participants and 8 NH participants slowed their rate with AAF.

CONCLUSIONS

Speaking with MAF appears to increase fluency in a subset of individuals with APH/AOS, indicating that overreliance on auditory feedback monitoring may contribute to their disorder presentation. The distinction between responders and nonresponders was not linked to AOS diagnosis, so additional work is needed to develop hypotheses for candidacy and underlying control mechanisms.

Behavioral and neurobiological correlates of childhood apraxia of speech in Italian children

Childhood apraxia of speech (CAS) is a neurogenic Speech Sound Disorder whose etiology and neurobiological correlates are still unclear. In the present study, 32 Italian children with idiopathic CAS underwent a comprehensive speech and language, genetic and neuroradiological investigation aimed to gather information on the possible behavioral and neurobiological markers of the disorder. The results revealed four main aggregations of behavioral symptoms that indicate a multi-deficit disorder involving both motor-speech and language competence. Six children presented with chromosomal alterations. The familial aggregation rate for speech and language difficulties and the male to female ratio were both very high in the whole sample, supporting the hypothesis that genetic factors make substantial contribution to the risk of CAS. As expected in accordance with the diagnosis of idiopathic CAS, conventional MRI did not reveal macrostructural pathogenic neuroanatomical abnormalities, suggesting that CAS may be due to brain microstructural alterations.

Word production inconsistency of Singaporean-English-speaking adolescents with Down Syndrome

BACKGROUND

The nature of speech disorders in individuals with Down Syndrome (DS) remains controversial despite various explanations put forth in the literature to account for the observed speech profiles. A high level of word production inconsistency in children with DS has led researchers to query whether the inconsistency continues into adolescence, and if the inconsistency stems from inconsistent phonological disorder (IPD) or childhood apraxia of speech (CAS). Of the studies that have been published, most suggest that the speech profile of individuals with DS is delayed, while a few recent studies suggest a combination of delayed and disordered patterns. However, no studies have explored the nature of word production inconsistency in this population, and the relationship between word production inconsistency, receptive vocabulary and severity of speech disorder.

AIMS

To investigate in a pilot study the extent of word production inconsistency in adolescents with DS and to examine the correlations between word production inconsistency, measures of receptive vocabulary, severity of speech disorder and oromotor skills in adolescents with DS.

METHODS & PROCEDURES

The participants were 32 native speakers of Singaporean-English adolescents, comprising 16 participants with DS and 16 typically developing (TD) participants. The participants completed a battery of standardized speech and language assessments, including The Diagnostic Evaluation of Articulation and Phonology (DEAP) assessment. Results from each test were correlated to determine relationships. Qualitative analyses were also carried out on all the data collected.

OUTCOMES & RESULTS

In this study, seven out of 16 participants with DS scored above 40% on word production inconsistency, a diagnostic criterion for IPD. In addition, all participants with DS performed poorly on the oromotor assessment of DEAP. The overall speech profile observed did not exactly correspond with the cluster symptoms observed in children with IPD or CAS.

CONCLUSIONS & IMPLICATIONS

Word production inconsistency is a noticeable feature in the speech of individuals with DS. In addition, the speech profiles of individuals with DS consist of atypical and unusual errors alongside developmental errors. Significant correlations were found between the measures investigated, suggesting that speech disorder in DS is multifactorial. The results from this study will help to improve differential diagnosis of speech disorders and individualized treatment plans in the population with DS.

Cognitive Functions in Childhood Apraxia of Speech

PURPOSE

Childhood apraxia of speech (CAS) is diagnosed on the basis of specific speech characteristics, in the absence of problems in hearing, intelligence, and language comprehension. This does not preclude the possibility that children with this speech disorder might demonstrate additional problems.

METHOD

Cognitive functions were investigated in 3 domains: complex sensorimotor and sequential memory functions, simple sensorimotor functions, and nonrelated control functions. Seventeen children with CAS were compared with 17 children with normal speech development at 2 occasions within 15 months.

RESULTS

The children with CAS showed overall lower scores but similar improvement at Occasion 2 compared with the typically developing controls, indicating an overall delay in the development of cognitive functions. However, a specific deviant development in sequential abilities was found as well, indicated by significantly lower scores at Occasion 2 as compared with younger control children at Occasion 1. Furthermore, the scores on the complex sensorimotor and sequential memory tasks were significantly correlated with the severity of the speech impairment.

CONCLUSIONS

These results suggest that CAS involves a symptom complex that not only comprises errors of sequencing speech movements but implicates comorbidity in nonverbal sequential functioning in most children with CAS.

Feedforward and feedback control in apraxia of speech: effects of noise masking on vowel production

PURPOSE

This study was designed to test two hypotheses about apraxia of speech (AOS) derived from the Directions Into Velocities of Articulators (DIVA) model (Guenther et al., 2006): the feedforward system deficit hypothesis and the feedback system deficit hypothesis.

METHOD

The authors used noise masking to minimize auditory feedback during speech. Six speakers with AOS and aphasia, 4 with aphasia without AOS, and 2 groups of speakers without impairment (younger and older adults) participated. Acoustic measures of vowel contrast, variability, and duration were analyzed.

RESULTS

Younger, but not older, speakers without impairment showed significantly reduced vowel contrast with noise masking. Relative to older controls, the AOS group showed longer vowel durations overall (regardless of masking condition) and a greater reduction in vowel contrast under masking conditions. There were no significant differences in variability. Three of the 6 speakers with AOS demonstrated the group pattern. Speakers with aphasia without AOS did not differ from controls in contrast, duration, or variability.

CONCLUSION

The greater reduction in vowel contrast with masking noise for the AOS group is consistent with the feedforward system deficit hypothesis but not with the feedback system deficit hypothesis; however, effects were small and not present in all individual speakers with AOS. Theoretical implications and alternative interpretations of these findings are discussed.

Reliance on auditory feedback in children with childhood apraxia of speech

Children with childhood apraxia of speech (CAS) have been hypothesized to continuously monitor their speech through auditory feedback to minimize speech errors. We used an auditory masking paradigm to determine the effect of attenuating auditory feedback on speech in 30 children: 9 with CAS, 10 with speech delay, and 11 with typical development. The masking only affected the speech of children with CAS as measured by voice onset time and vowel space area. These findings provide preliminary support for greater reliance on auditory feedback among children with CAS.

LEARNING OUTCOMES

Readers of this article should be able to (i) describe the motivation for investigating the role of auditory feedback in children with CAS; (ii) report the effects of feedback attenuation on speech production in children with CAS, speech delay, and typical development, and (iii) understand how the current findings may support a feedforward program deficit in children with CAS.

Creation and design of a test for the Evaluation of Upper Limb Apraxia (EULA) based on a cognitive model: a pilot study

INTRODUCTION

Apraxia is regarded as neurological disorder characterized by a loss of ability to execute and carry out skilled movements and gestures despite intact motor and sensory systems, coordination, and comprehension. As reflected in the specialized literature, there are currently few tests that provide a global evaluation of this syndrome. This research created and designed a test for the Evaluation of Upper Limb Apraxia (EULA), based on theoretical models of apraxia.

SUBJECTS AND METHODS

A sample of 57 patients was selected with subjective cognitive manifestations (complaints of cognitive impairment) and 39 subjects without cognitive impairment. Both groups were given the EULA test as well as other tests. The structure of the EULA was verified with principal components factor analysis, and the reliability and validity of this instrument were also calculated.

RESULTS

The factor analysis classified all of the items in the test in nine factors with an explained total variance of 69.91%. The high reliability of the test was reflected in a Cronbach's alpha of 0.929 and a Guttman split-half coefficient of 0.870. The construct validity was also satisfactory as shown in the significant correlation of six of the nine factors in the test with two other well-known apraxia subtests.

CONCLUSIONS

The healthy subjects had a higher test score than the subjects with complaints of cognitive impairment, which confirmed the reliability and construct validity of the EULA.

Performance of motor imitation in children with and without dyspraxia

BACKGROUND

Motor imitation is truly essential for young children to learn new motor skills, social behavior and skilled acts or praxis. The present study aimed to investigate motor imitation ability between typically-developing children and dyspraxic children and to examine the development trends in both children groups.

MATERIAL AND METHOD

The comparison ofmotor imitation was studied in 55 typically-developing children and 59 dyspraxic children aged 5 to 8 years. The Motor Imitation subtest consisted of two sections, imitation of postures and imitation of verbal instructions. Typically-developing children and dyspraxic children were examined for developmental trends. The independent samples t-test was used to analyze the differences between both groups. Two-way analysis of variance (ANOVA) was used to analyze inter-age differences for each age group.

RESULTS

The results revealed significant differences between dyspraxic and typically-developing children. Both typically-developing and dyspraxic children demonstrated age trends. The older children scored higher than younger children.

CONCLUSION

Imitation is a primary learning strategy of young children. It is essential that children with dyspraxia receive early detection and need effective intervention. Typically-developing children and dyspraxic children showed higher mean score on the Imitation of Posture section than the Verbal Instructions section. Motor imitation competency, therefore, changes and improves with age.

Handmade task tracking applied to cognitive rehabilitation

This article presents research focused on tracking manual tasks that are applied in cognitive rehabilitation so as to analyze the movements of patients who suffer from Apraxia and Action Disorganization Syndrome (AADS). This kind of patients find executing Activities of Daily Living (ADL) too difficult due to the loss of memory and capacity to carry out sequential tasks or the impossibility of associating different objects with their functions. This contribution is developed from the work of Universidad Politécnica de Madrid and Technical University of Munich in collaboration with The University of Birmingham. The KinectTM for Windows© device is used for this purpose. The data collected is compared to an ultrasonic motion capture system. The results indicate a moderate to strong correlation between signals. They also verify that KinectTM is very suitable and inexpensive. Moreover, it turns out to be a motion-capture system quite easy to implement for kinematics analysis in ADL.

Prelinguistic communication development in children with childhood apraxia of speech: a retrospective analysis

In a retrospective study of prelinguistic communication development, clinically referred preschool children (n = 9) aged 3-4 years, who as infants had failed a community-based screening program, were evaluated for features of childhood apraxia of speech (CAS). Four children showed no features and either delayed or normal language, five had from three-to-seven CAS features and all exhibited delayed language. These children were matched by age with 21 children with typically-developing (TD) speech and language skills. Case-control comparisons of retrospective data from 9 months of age for two participants with more severe features of CAS at preschool age showed a dissociated pattern with low expressive quotients on the Receptive-Expressive Emergent Language Assessment-Second Edition (REEL-2) and records of infrequent babbling, but normal receptive quotients. However, other profiles were observed. Two children with milder CAS features showed poor receptive and expressive development similar to other clinically referred children with no CAS features, and one child with severe CAS features showed poor receptive but normal expressive developmental milestones at 9 months and records of frequent babbling. Results suggest some but not all children with features of suspected CAS have a selective deficit originating within speech motor development.

[Dementia and the gestures surrounding meals]

The nursing research project "Praxalim" was initiated by a nursing team. Confronted with Alzheimer's disease and related illnesses, the nursing staff wanted to work on help with daily living tasks and in particular meals.

Identifying residual speech sound disorders in bilingual children: a Japanese-english case study

PURPOSE

To describe (a) the assessment of residual speech sound disorders (SSDs) in bilinguals by distinguishing speech patterns associated with second language acquisition from patterns associated with misarticulations and (b) how assessment of domains such as speech motor control and phonological awareness can provide a more complete understanding of SSDs in bilinguals.

METHOD

A review of Japanese phonology is provided to offer a context for understanding the transfer of Japanese to English productions. A case study of an 11-year-old is presented, demonstrating parallel speech assessments in English and Japanese. Speech motor and phonological awareness tasks were conducted in both languages.

RESULTS

Several patterns were observed in the participant's English that could be plausibly explained by the influence of Japanese phonology. However, errors indicating a residual SSD were observed in both Japanese and English. A speech motor assessment suggested possible speech motor control problems, and phonological awareness was judged to be within the typical range of performance in both languages.

CONCLUSION

Understanding the phonological characteristics of the native language can help clinicians recognize speech patterns in the second language associated with transfer. Once these differences are understood, patterns associated with a residual SSD can be identified. Supplementing a relational speech analysis with measures of speech motor control and phonological awareness can provide a more comprehensive understanding of a client's strengths and needs.

Lexical and phonological development in children with childhood apraxia of speech--a commentary on Stoel-Gammon's 'Relationships between lexical and phonological development in young children'

Although not the focus of her article, phonological development in young children with speech sound disorders of various types is highly germane to Stoel-Gammon's discussion (this issue) for at least two primary reasons. Most obvious is that typical processes and milestones of phonological development are the standards and benchmarks against which we measure disorder and delay. Factors that impact children without disorders may suggest underlying causes or co-occurring symptoms of speech sound deficits, prognostic indicators of improvement, appropriate remediation strategies or some combination of these. Equally important is the fact that studying children with disorders can help us to verify and, in some cases, even unpack relationships among factors that are so closely interwoven in children who develop their phonologies at the typically very rapid rate that their individual influences cannot be discerned. Childhood Apraxia of Speech (CAS) is a particularly interesting case in point because, while it is universally accepted to be a motor speech disorder, symptoms include deficits in speech perception and often in literacy-related skills as well.

Production variability and single word intelligibility in aphasia and apraxia of speech

This study was designed to estimate test-retest reliability of orthographic speech intelligibility testing in speakers with aphasia and AOS and to examine its relationship to the consistency of speaker and listener responses. Monosyllabic single word speech samples were recorded from 13 speakers with coexisting aphasia and AOS. These words were transcribed phonetically by two trained listeners and also presented to non-brain-damaged listeners for identification in a computerized speech intelligibility test. Overall intelligibility scores were computed for each speaker, and word-by-word responses for individual words were examined for both speaker and listener consistency. The clinical feasibility of the approach was supported by a strong correlation between scores from the phonetic transcription and speech intelligibility tests and by strong test-retest reliability for all speakers. Detailed analyses of individual responses indicated that the intelligibility test stability was not due to consistency either in the kind of errors speakers made or in the responses listeners gave when they heard a word different from the target.

LEARNING OUTCOMES

The reader will be able to describe the purpose of single word speech intelligibility testing in individuals with aphasia and apraxia of speech and to discuss the relationship between word-by-word production consistency and overall test-retest reliability.

Neurological and psychiatric aspects of corpus callosum genesis

This article reports the case of a patient with partial agenesis of the corpus callosum manifested with corpus callosum syndrome together with signs of brain hemispheres dysfunction: mental impairment, epilepsy and pyramidal signs. The patient's malformation is combined with left-handedness while signs of callosal disconnection are not present. Mild cognitive impairment and late epilepsy onset require a multidisciplinary approach since the patient also displays elements of central nervous system malformations.

Effects of online augmented kinematic and perceptual feedback on treatment of speech movements in apraxia of speech

Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and temporal parameters of movement. Research on motor learning suggests that augmented feedback may provide a beneficial effect for training movement. This study examined the effects of the presence and frequency of online augmented visual kinematic feedback (AVKF) and clinician-provided perceptual feedback on speech accuracy in 2 adults with acquired AOS. Within a single-subject multiple-baseline design, AVKF was provided using electromagnetic midsagittal articulography (EMA) in 2 feedback conditions (50 or 100%). Articulator placement was specified for speech motor targets (SMTs). Treated and baselined SMTs were in the initial or final position of single-syllable words, in varying consonant-vowel or vowel-consonant contexts. SMTs were selected based on each participant's pre-assessed erred productions. Productions were digitally recorded and online perceptual judgments of accuracy (including segment and intersegment distortions) were made. Inter- and intra-judge reliability for perceptual accuracy was high. Results measured by visual inspection and effect size revealed positive acquisition and generalization effects for both participants. Generalization occurred across vowel contexts and to untreated probes. Results of the frequency manipulation were confounded by presentation order. Maintenance of learned and generalized effects were demonstrated for 1 participant. These data provide support for the role of augmented feedback in treating speech movements that result in perceptually accurate speech production. Future investigations will explore the independent contributions of each feedback type (i.e. kinematic and perceptual) in producing efficient and effective training of SMTs in persons with AOS.

[Neuropsychological signs in patients with arteriovenous malformations, cavernomas and hematomas of cerebellum]

Neuropsychological assessment was performed in 13 patients with arteriovenous malformations and 12 with cavernomas and hematomas of cerebellum before and after surgery. In all patients we identified syndromes that were similar to the damage of different areas of neocortex (predominately frontal lobe). Apraxia and disturbance of verbal memory were the most frequent signs. Half of patients after AVM embolization and all patients after direct surgery developed deterioration of verbal memory. Some patients after manipulations on right cerebellar hemisphere had micrography and perseverations. There were no severe mental disorders neither before nor after surgery. That was controversial to other similar studies. The most severe cognitive disorders were found after surgery on superior cerebellar artery and its branches.

[Case of callosal disconnection syndrome with a chief complaint of right-hand disability, despite presence of left-hand diagonistic dyspraxia]

e report the case of 48-year-old right-handed male patient with an infarction affecting most part of the body and the splenium of the left half of the corpus callosum. Neuropsychological examination revealed typical signs of callosal disconnection including left-sided apraxia, diagonistic dyspraxia, left-sided agraphia, left-hand tactile anomia, left hemialexia, and right-sided constructional disability. Moreover, he complained of impairment in activities involving the right hand disability and agraphia. He could not stop behaving with his right hand when he had a vague idea. For example, he involuntarily picked up a tea bottle with his right hand when he had a desire to drink, although the action was not appropriate to that occasion. The imitation and utilization behavior did not imply this case, because his right hand behaviors were not exaggerated in response to external stimuli, such as the gestures of the examiner or the subjects in front of the patient. Unexpectedly, he complained about impairment of the activity of his right hand and was unaware of left hand apraxia or diagonistic dyspraxia; this trend continued for 6 months, at the time of this writing. We argue that the patient may have been subconsciouly aware of the symptoms of his left hand but had not verbalized them.

The influence of visual and auditory information on the perception of speech and non-speech oral movements in patients with left hemisphere lesions

Patients with lesions of the left hemisphere often suffer from oral-facial apraxia, apraxia of speech, and aphasia. In these patients, visual features often play a critical role in speech and language therapy, when pictured lip shapes or the therapist's visible mouth movements are used to facilitate speech production and articulation. This demands audiovisual processing both in speech and language treatment and in the diagnosis of oral-facial apraxia. The purpose of this study was to investigate differences in audiovisual perception of speech as compared to non-speech oral gestures. Bimodal and unimodal speech and non-speech items were used and additionally discordant stimuli constructed, which were presented for imitation. This study examined a group of healthy volunteers and a group of patients with lesions of the left hemisphere. Patients made substantially more errors than controls, but the factors influencing imitation accuracy were more or less the same in both groups. Error analyses in both groups suggested different types of representations for speech as compared to the non-speech domain, with speech having a stronger weight on the auditory modality and non-speech processing on the visual modality. Additionally, this study was able to show that the McGurk effect is not limited to speech.

Speech perception in children with speech output disorders

Research in the field of speech production pathology is dominated by describing deficits in output. However, perceptual problems might underlie, precede, or interact with production disorders. The present study hypothesizes that the level of the production disorders is linked to level of perception disorders, thus lower-order production problems (such as childhood apraxia of speech; CAS) are linked to lower-order perception problems and higher-order production problems (phonological disorder; PD) are linked to higher-order perception problems. For this, various perception tasks were administered (non-word auditory discrimination task, word rhyming task, categorical classification, and discrimination task) in children with CAS, PD, or a mixture. The results show that children with PD only show higher-order perception problems, whereas children with CAS have difficulties on both lower- and higher-order perception tasks. In children with CAS, difficulties at lower-order processes might affect the higher-order processes in development. Furthermore, significant correlations were found between production and perception scores at different levels. Thus, a link between perception and production seems to be evident.

[New approach to apraxia]

Our collective understanding of our approach to apraxia has not dramatically changed over the last century. The classical approach to apraxia has occasionally caused confusion and disagreements because it lacks established definitions for apraxia and related terms such as "praxicon" or "ideation". Rather, the current system allows each researcher to define these terms differently, making it extremely difficult to compare cases reported by different researchers. New approaches, however, are providing more concrete definitions, enabling us to describe apraxic disorders more operationally, this may help prevent the disagreement concerning these definitions. A more recent approach, demonstrated in several reports, focuses on the interactions between "body" and "objects". Another approach concentrates on information processing such as "online processing" and the retrieval of stored knowledge. These new approaches to apraxia have the potential to improve our ability to communicate about this condition. In future studies, these conceps should be integrated into the classical approach to create a single, workable model for understanding apraxic syndromes.

[Possible mechanism of body part as object and hand closing-in in apraxia]

We report a case of apraxia with pantomime where the patient exhibited body part as object (BPO) and hand closing-in errors as the symptoms of apraxia. The patient was a 52-year-old right-handed man who was clinically diagnosed with corticobasal degeneration. We tested the praxis ability of the patient by using 2 standard tests for apraxia: transitive gestures in response to verbal command and transitive gestures in response to visually presented objects. During the tests, the patient showed BPO errors and occasionally reached for the presented objects when he was instructed to pantomime their use without touching the objects (hand closing-in). Both BPO and hand closing-in were observed immediately after he was instructed to perform the target gestures. Hand closing-in was frequently observed when he was instructed to perform transitive gestures in response to visually presented objects. From the above results, we concluded that BPO is attributable to the inability to form precise finger postures for grasping objects, resulting in the "contamination" of the motor command by the information regarding the shape of the objects. Hand closing-in is considered to be caused by increased response to the presented object because of motor activation by perceived object images. On the whole, BPO and hand closing-in can be considered to be triggered by an overlap of objects with body images because of imprecise motor commands and increased responses to the object image.

Concepts and categories: a cognitive neuropsychological perspective

One of the most provocative and exciting issues in cognitive science is how neural specificity for semantic categories of common objects arises in the functional architecture of the brain. More than two decades of research on the neuropsychological phenomenon of category-specific semantic deficits has generated detailed claims about the organization and representation of conceptual knowledge. More recently, researchers have sought to test hypotheses developed on the basis of neuropsychological evidence with functional imaging. From those two fields, the empirical generalization emerges that object domain and sensory modality jointly constrain the organization of knowledge in the brain. At the same time, research within the embodied cognition framework has highlighted the need to articulate how information is communicated between the sensory and motor systems, and processes that represent and generalize abstract information. Those developments point toward a new approach for understanding category specificity in terms of the coordinated influences of diverse regions and cognitive systems.

Embodiment in communication--aphasia, apraxia and the possible role of mirroring and imitation

The role of embodiment in communication is attracting an increased interest. This interest is to some extent caused by hypotheses and findings concerning mirror neurons in macaques, that is, neurons that are activated by production as well as perception of, for example, a certain movement of action. Mirror neurons seem to provide a fairly simple mechanism for acting, perceiving, imitating and pantomime, which could be crucial to the development of human communication and language. A number of theories try to extend similar ideas in describing human embodied communication. Some of the consequences of these theories are: (1) the close relation between speech and gestures; (2) the close relation between speech/language and praxis; and (3) the reconsideration of the importance for communication of more automatized versus more controlled processing. The purpose here is to point to possible consequences for clinical research and therapy concerning language disorders.

Central timing deficits in subtypes of primary speech disorders

Childhood apraxia of speech (CAS) is a proposed speech disorder subtype that interferes with motor planning and/or programming, affecting prosody in many cases. Pilot data (Peter & Stoel-Gammon, 2005) were consistent with the notion that deficits in timing accuracy in speech and music-related tasks may be associated with CAS. This study replicated and expanded earlier findings. Eleven children with speech disorders and age-and gender-matched controls participated in non-word imitation, clapped rhythm imitation, and paced repetitive tapping tasks. Results suggest a central timing deficit, expressed in both the oral and the limb modality, and observable in two different types of timing measures, overall rhythmic structures and small-scale durations. Associations among timing measures were strongest in the participants with speech disorders, who also showed lower timing accuracy than the controls in all measures. The number of observed CAS characteristics was associated with timing deficits.

Autistic traits and cognitive performance in young people with mild intellectual impairment

Cognitive performance and the relationship between theory of mind (TOM), weak central coherence and executive function were investigated in a cohort of young people with additional learning needs. Participants were categorized by social communication questionnaire score into groups of 10 individuals within the autistic spectrum disorder (ASD) range, 14 within the pervasive developmental disorder range and 18 with few autistic traits. The ASD group were significantly poorer than the other groups on a test of cognitive flexibility. In the ASD group only, there was a strong relationship between executive performance and TOM which remained after controlling for IQ. Our findings suggest that the relationship between cognitive traits may more reliably distinguish autism than the presence of individual deficits alone.

The role of higher-level cognitive function in gait: executive dysfunction contributes to fall risk in Alzheimer's disease

Alzheimer's disease (AD) is generally understood as primarily affecting cognition while sparing motor function, at least until the later stages of the disease. Studies reported over the past 10 years, however, have documented a prevalence of falls in AD patients significantly higher than in age-matched normal elders; also persons with AD have been observed to have different walking patterns with characteristics that increase gait instability. Recent work in cognitive neuroscience has begun to demonstrate the necessity of intact cognition, particularly executive function, for competent motor control. We put the pieces of this puzzle together and review the current state of knowledge about gait and cognition in general along with an exploration of the association between dementia, gait impairment and falls in AD. We also briefly examine the current treatment of gait instability in AD, mainly exercise, and propose a new approach targeting cognition.

An experimental investigation of the automatic/voluntary dissociation in limb apraxia

The ability of apraxic patients to perform gestures in everyday life is a controversial issue. In this paper, we aimed to evaluate the automatic/voluntary dissociation (AVD) in four patients affected by clinically relevant limb apraxia. For this purpose, we sampled different kinds of gestures belonging to patients' motor repertoire and then assessed their production in a testing session. Our experimental procedure consisted of two steps: in the first phase, we recorded gestures produced by patients in two natural conditions; in the second phase, we assessed production of correctly produced tool-actions, and of spontaneous non tool-actions and meaningless conversational (cohesive and beats) gestures under different modalities. AVD was observed for all types of gestures, albeit to different degree in single patients. The present findings demonstrate that the context provides strong bottom-up cues for the retrieval of motor patterns, while artificial testing conditions impose an additional cognitive load.