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Speakers with motor speech disorders (MSD) present challenges in speech production, one of them being the difficulty to adapt their speech to different modes. However, it is unclear whether different types of MSD are similarly affected when it comes to adapting their speech to various communication contexts. This study investigates the encoding of speech modes in individuals with AoS following focal brain damage and in individuals with hypokinetic dysarthria (HD) secondary to Parkinson's disease. Participants with mild-to-moderate MSD and their age-matched controls performed a delayed production task of pseudo-words in two speech modes: normal and whispered speech. While overall accuracy did not differ significantly across speech modes, participants with AoS exhibited longer response latencies for whispered speech, reflecting difficulties in the initiation of utterances requiring an unvoiced production. In contrast, participants with HD showed faster response latencies for whispered speech, indicating that this speech mode is easier to encode/control for this population. Acoustic durations followed these same trends, with participants with AoS showing greater lengthening for whispered speech as compared to controls and to participants with HD, while participants with HD exhibited milder lengthening. Contrary to the predictions of speech production models, suggesting that speech mode changes might be particularly difficult in dysarthria, the present results suggest that speech mode adaptation rather seems particularly costly for participants with AoS. [ABSTRACT FROM AUTHOR]

Speech is an extensively overlearned oromotor behaviour that becomes more automatised over the years due to the storage of their motor routines. To determine when this storage occurs in development, the EEG/ERP spatiotemporal dynamics underlying speech-motor planning were investigated in three groups: children, adolescents and adults. The production of speech was contrasted to sounded non-speech gestures that use the same effectors as speech but are not as frequently trained. Non-speech motor codes are assumed to be individually planned on the go, instead of being stored as motor routines. Neural results revealed a gradual differentiation between speech and non-speech motor planning with age: while ERPs did not differ in children, adolescents and adults showed gradually increasing differences in amplitudes and in topographies between speech and non-speech. This suggest that the speech motor code storage is not completely established yet in 7–9-year-old children but later during development, in early adolescence. [ABSTRACT FROM AUTHOR]

Oral diadochokinetic (DDK) tasks are widely used in the assessment of patients with motor speech disorders (MSD). They require the repetition of homogeneous and of heterogeneous syllables at a maximum rate. The nature of DDK tasks is a matter of debate: although they are usually considered as "non-speech", given the involvement of real speech syllables, they have also been recognized to share more properties and requirements with speech as compared to other oromotor behaviours (i.e., non-speech gestures). Additionally, the production of heterogeneous syllables has been suggested to exhibit closer correspondence with speech given the production of a cluster of different syllables, as compared to the repetition of a monosyllable. Each DDK task being differently related to speech supports the assumption of a continuum between speech and other oromotor processes, in which tasks with increasingly speech-like properties may overlap to a larger extent with speech. To test the potentially differential relationship between speech and DDK tasks in patients with MSD. Traditional views of MSD claim that speech and other oromotor behaviours are impaired in patients with dysarthria, while patients with AoS present with speech being exclusively compromised. This suggests that DDK tasks should be differently affected in these two MSD populations. Moreover, in the framework of a continuum, oromotor tasks sharing some characteristics with speech (i.e., heterogeneous DDK task) should also be impaired in patients with AoS. Syllabic rates of a sentence production (SP) task are contrasted with those of homogeneous and heterogeneous DDK tasks in three pathological populations: patients with dysarthria due to Parkinson's Disease (PD, n = 10) or due to amyotrophic lateral sclerosis (ALS, n = 10) and patients with apraxia of speech (AoS, n = 10); and 30 matched neurotypical controls. While patients with PD show similar rates across the SP and the DDK tasks relative to control speakers, patients with ALS display significantly slower rates across all tasks as compared to matched controls. Patients with AoS show reduced performances in the SP and in the heterogeneous DDK task, but not on the repetition of homogeneous syllables. The findings of this study confirm that the repetition of heterogeneous syllables shares more principles and properties with speech than the homogeneous DDK task. This dissimilar relationship between speech and the two types of DDK tasks points to the existence of a continuum among oromotor tasks. [ABSTRACT FROM AUTHOR]

PURPOSE: Bilingual aphasia generally affects both languages. However, the age of acquisition of the second language (L2) seems to play a role in the anatomo-functional correlation of the syntactical/grammatical processes, thus potentially influencing the L2 syntactic impairment following a stroke. The present study aims to analyze the influence of late age of acquisition of the L2 on syntactic impairment in bilingual aphasic patients. METHODS: Twelve late bilingual participants (speaking French as L2 and either English, German, Italian or Spanish as L1) with stroke-induced aphasia participated in the study. The MAST or BAT aphasia batteries were used to evaluate overall aphasia score. An auditory syntactic judgement task was developed and used to test participants syntactic performance. RESULTS: The overall aphasia scores did not differ between L1 and L2. In a multiple case analysis, only one patient had lower scores in L2. However, four patients presented significantly lower performances in syntactic processing in the late L2 than in their native language (L1). In these four patients the infarct was localized, either exclusively or at least partially, in the pre-rolandic region. CONCLUSION: This pilot study suggests that, in late bilingual aphasics, syntactic judgment abilities may be more severely impaired in L2, and that this syntactic deficit is most likely to occur following anterior lesions. [ABSTRACT FROM AUTHOR]

Background: The observation of a syllable frequency effect on production latencies in healthy speakers has been an argument in favour of stored syllables in speech production. In Levelt, Roelofs, and Meyer's (1999) model of speech production, syllabic representations are accessed during phonetic encoding. Neurolinguistic studies have provided convergent evidence of a syllable frequency effect on production accuracy in speakers with acquired language disorders. However, the observation that syllable frequency also affected production in aphasic speakers with a pre-phonetic impairment (conduction aphasia and Wernicke's aphasia) seems in contradiction to the phonetic locus of syllabic representations. Aims: We illustrate the points of convergences and divergences between psycholinguistic and neurolinguistic results on the locus of the syllable frequency effect and explore whether a syllable frequency effect is observed in apraxia of speech (AoS) and in conduction aphasia when participants are tested with the same material. Methods & Procedures: Reading and repetition was elicited with monosyllabic words (Experiment A) and with bisyllabic pseudowords (Experiment B) composed of high- or low-frequency syllables. Three speakers with AoS and three speakers with conduction aphasia participated in each experiment. Outcomes & Results: Both subgroups displayed a tendency for a syllable frequency effect on production accuracy. A significant effect of syllable frequency was observed in each experiment in a participant with AoS and in a participant with conduction aphasia. Conclusions: The data confirmed similar syllable frequency effects in speakers with AoS and in conduction aphasia when tested with the same eliciting material. We discuss these apparently contradictory observations and suggest an explanation for the origin of the syllable frequency effect in these two populations. [ABSTRACT FROM AUTHOR]

Polyglot speakers who become aphasics are not necessarily affected to the same extent in each language. In some cases there is a mixing of the different languages or a switching between languages and in very rare cases the switch is to the language seldom if ever used in everyday live. We report a French-speaking aphasic, who switched paradoxically from his mother tongue (French) to a second language (German) which he had learned at school but barely mastered and hardly ever spoke, and kept using German most of the time. We tried to understand the mechanism responsible for that phenomenon by reviewing the actual hypothesis of multi-language organization. We concluded, in line with previous reports, that our case used his metalinguistic knowledge to compensate for his inability to access his linguistic skills. [ABSTRACT FROM AUTHOR]

Introduction/Background Several studies identified age, gender, handedness, lesion size, stroke subtype, aphasia/stroke initial severity as prognostic factors for recovery from aphasia. However, prediction of recovery still remains difficult to establish initially for patients with initial severe aphasia. The aim of this study was to identify the lesion location associated with poor recovery. Material and method One hunderd aphasic patients were included within fourteen days after a first ischemic or haemorrhagic stroke of the left hemisphere and had analysable MRI sequences. The severity of aphasia was determined using the Aphasia Severity Rating Scale in the acute phase and six months post-stroke. The ASRS is a 6-point Likert scale from the lowest score 0 to 5. A severe aphasia initially was defined as an ASRS score < 3. Good recovery at M6 was defined as an ASRS = 4–5. In a first step, axial diffusion-weighted images, or T2*-weighted images for intra-cerebral haemorrhage, were imported. Lesions were drawn manually as regions of interest blinded to clinical data. Images were normalized to a standard brain template. The resulting normalized lesion maps were analysed in a VLSM approach, which applies the graded information at the behavioural level to voxel-wise binary lesion information. The resulting maps were corrected for multiple comparisons. Results Regarding all patients, a better outcome was significantly associated ( P < 0.01) with lesion excluding the following areas of the left hemisphere: Putamen, transverse temporal gyrus (Heschl gyrus), Insula, Rolandic Operculum. Regarding patients with severe aphasia initially, a poor recovery (i.e. ASRS at M6 < 4) was significantly associated ( P < 0.05) with lesion in the Putamen and transverse temporal gyrus (Heschl gyrus). Conclusion The present study identified critical areas associated with poor outcomes for aphasia, particularly lesions of the superior temporal gyrus for patients with severe aphasia initially. These findings are in line with previous results in the literature. [ABSTRACT FROM AUTHOR]