Regular ArticleThe Foreign Accent Syndrome: A Reconsideration
Abstract
This study compared the post-CVA speech of a patient presenting with the foreign accent syndrome (FAS) to both a premorbid baseline for that patient and to similarly analyzed data from an earlier reported case of FAS. The object of this research was to provide quantitative acoustic data to determine whether: (1) the constellation of phonetic features associated with FAS is the same across patients and (2) a common neural mechanism underlies FAS. Acoustic parameters investigated included features of consonant production (voicing, place and manner of articulation), vowel production (formant frequency and duration), and prosody. Results supported the characterization of FAS patients as having a “generic” foreign accent and the hypothesis that FAS deficits are qualitatively different from that of Broca's aphasia. However, comparison of this case with recent studies revealed the extent to which the constellation of phonetic features may vary among FAS patients, challenging the notion that a general prosodic disturbance is the sole underlying mechanism in FAS.
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Segmental diagnostics of neurogenic and functional foreign accent syndrome
2021, Journal of NeurolinguisticsPrevious research suggests differences in speech patterns between speakers with foreign accent syndrome (FAS) associated with a neurological (neurogenic FAS) versus a psychological aetiology (functional FAS). Differentiating sub-types holds important clinical implications, affecting the nature of follow-up assessment and treatment. To date, there exist no systematic comparisons between these sub-groups. To investigate possible differences, we employed auditory and acoustic analyses to compare schwa insertion and /r/production in speakers with FAS (12 neurogenic, 5 functional).
Schwa insertion and /r/ production demonstrated significant differences between groups. Neurogenic aetiology was associated with higher within and between speaker performance consistency and congruence of derailments with phonetic-phonological and neurological accounts of ‘error’ origin. Individuals with functional FAS showed significant within and between speaker variability, which was poorly accounted for by linguistic and speech motor control explanations.
We argue that schwa insertion and differences in /r/ realisations provide reliable and accessible variables for clinicians to employ to support differential diagnosis of functional versus neurogenic speech disorders. Findings are discussed in the context of understanding FAS and the broader context of understanding functional speech and language disorders.
Neural mechanisms of foreign accent syndrome: Lesion and network analysis
2021, NeuroImage: ClinicalForeign accent syndrome (FAS) is a rare acquired speech disorder wherein an individual’s spoken accent is perceived as “foreign.” Most reported cases involve left frontal brain lesions, but it is known that various other lesions can also cause FAS. To determine whether heterogeneous FAS-causing lesions are localized to a common functional speech network rather than to a single anatomical site, we employed a recently validated image analysis technique known as “lesion network mapping.”
We identified 25 published cases of acquired neurogenic FAS without aphasia, and mapped each lesion volume onto a reference brain. We next identified the network of brain regions functionally connected to each FAS lesion using a connectome dataset from normative participants. Network maps were then overlapped to identify common network sites across the lesions.
Classical lesion overlap analysis showed heterogeneity in lesion anatomical location, consistent with prior reports. However, at least 80% of lesions showed network overlap in the bilateral lower and middle portions of the precentral gyrus and in the medial frontal cortex. The left lower portion of the precentral gyrus is suggested to be the location of lesions causing apraxia of speech (AOS), and the middle portion is considered to be a larynx-specific motor area associated with the production of vowels and stop/nasal consonants and with the determination of pitch accent.
The lesions that cause FAS are anatomically heterogeneous, but they share a common functional network located in the bilateral posterior region of the frontal lobe. This network specifically includes not only the lower portion of the central gyrus, but also its middle region, which is referred to as the larynx motor cortex and is known to be associated with phonation. Our findings suggest that disrupted networks in FAS might be anatomically different from those in AOS.
Listener perceptions of foreignness, precision, and accent attribution in a case of foreign accent syndrome
2020, Journal of NeurolinguisticsThis paper will examine how listeners perceive foreignness, precision, and speaker origin in the speech of a speaker with neurogenic foreign accent syndrome, as compared to an unimpaired native speaker, an unimpaired foreign speaker, and a native speaker with ataxic dysarthria.
Listeners with and without experience in speech-language pathology rated degree of foreignness and precision of speech sounds of a speaker with neurogenic foreign accent syndrome as compared to (a) an unimpaired native speaker, (b) an unimpaired foreign speaker, and (c) a native speaker with ataxic dysarthria. Listeners also attributed national origin to each speaker and rated confidence in all their attributions and ratings.
Listeners rated a native speaker with foreign accent syndrome as less foreign than a true foreign speaker. They agreed less and were less accurate when attributing national origin to a speaker with foreign accent syndrome and were less confident in their attributions and ratings. Unexpectedly, listeners were equally as unsure when attributing origin to a native speaker with ataxic dysarthria as they were when attributing origin to a native speaker with foreign accent syndrome.
While previous literature has characterized foreign accent syndrome as perceptually unique in comparison to true foreign accents and other motor speech disorders, our results suggest that listeners do not universally discern a clear difference between foreign accent syndrome speech and other disordered speech. This may suggest that foreign accent syndrome is not a discrete diagnosis. If it is a discrete diagnosis, these results rebut the idea that foreign accent syndrome is the only motor speech disorder in which the speaker is perceived as foreign.
Non-Neurogenic Language Disorders: A Preliminary Classification
2018, PsychosomaticsFew publications deal with non-neurogenic language disorders (NNLDs), distinct from psychogenic speech disorders such as psychogenic dysphonia or stuttering. NNLDs are alterations in language owing to psychosomatic preoccupations, conversion disorder, psychiatric disorders, or other psychological reasons.
To identify and classify the range of NNLDs and their characteristics.
This review summarizes the literature on disturbances in language, broadly defined as the use of symbols for communication, which may have a psychogenic or psychiatric etiology.
The literature suggests a classification for NNLDs that includes psychogenic aphasia with dysgrammatism; psychogenic “lalias” including oxylalia and agitolalia, palilalia and echolalia, xenolalia, glossolalia, and coprolalia; psychologically-mediated word usage; psychotic language; and psychogenic forms of the foreign accent syndrome.
Clinicians and researchers have insufficiently emphasized the presence of NNLDs, their characteristics, and their identification. Yet, these disorders may be the first or predominant manifestation of a psychologically-mediated illness. There are 2 steps to recognition. The first is to know how to distinguish NNLDs from the manifestations of neurogenic language impairments after a neurological evaluation. The second step is awareness of specific associated and examination features that suggest the presence of a NNLD.
The role of the left putamen in multilingual language production
2013, Brain and LanguageSubcortical structures are a key component of bilingual language processing. For instance, there is now evidence that the head of the left caudate is involved in controlling languages in bilingual individuals. On the other hand, the left putamen is hypothesized to be involved in articulatory processes but little is known on its engagement in bilingual language processing. Here, our hypothesis was that the left putamen of multilinguals is engaged when producing words in the less proficient language. We investigated this issue with event-related functional Magnetic Resonance (er-fMRI) in a group of multilinguals (n = 14) and in monolinguals (n = 14) during a picture-naming task. Further, we hypothesized increased grey matter density in the left putamen as an effect of experience since multilinguals constantly face a major articulatory load (i.e., speaking multiple languages) during life. To test these hypotheses we measured structural differences between multilinguals and monolinguals using voxel-based morphometry (VBM).
Our results indicate that multilinguals have increased activation in the left putamen for a non-native language, but only if they are not highly proficient in that language. In addition, we found increased grey matter density in the left putamen of multilinguals compared to monolinguals. These findings highlight that the multilingual brain handles a complex articulatory repertoire (i.e., dealing with multiple languages) by inducing structural plasticity in the left putamen.
Accent attribution in speakers with Foreign accent syndrome
2013, Journal of Communication DisordersThe main aim of this experiment was to investigate the perception of Foreign Accent Syndrome in comparison to speakers with an authentic foreign accent.
Three groups of listeners attributed accents to conversational speech samples of 5 FAS speakers which were embedded amongst those of 5 speakers with a real foreign accent and 5 native speaker controls. The listening panels differed in their familiarity with foreign accented speech and speech pathology.
The findings indicate that listeners’ perceptual responses to the three groups of speakers were essentially different at all levels of analysis. The native speaker controls were unequivocally recognized as native speakers of Dutch while the speakers with a real foreign accent were very reliably assessed as non-native speakers. The speakers with Foreign Accent Syndrome, however, were in some sense perceived as foreign and in some sense as native by listeners, but not as foreign as speakers with a real foreign accent nor as native as real native speakers. These results are accounted for in terms of a misinterpretation of markers of speech pathology as markers regional affiliation.
The findings of the experiment are consistent with the idea that the very nature of the foreign accent is different in both groups of speakers, although it cannot be fully excluded that the foreign impression in the two groups is one of degree.
Learning outcomes: Readers are able to: (1) define Foreign Accent Syndrome as a motor speech disorder and identify the different subtypes of FAS, (2) describe the most important differences in listeners’ perceptual reactions to FAS and real foreign accents, and (3) discuss the findings of the present study in relation to other studies investigating accent attribution in FAS.