[A case of conduction aphasia with specific jargon utterance].

We report a patient with bilateral hemispheric lesions caused by two episodes of cerebral infarction who exhibited conduction aphasia with unique jargon. The patient was an 84-year-old, right-handed man. Beginning after the second episode of cerebral infarction (defined as the time of symptom onset), neologistic jargon and an iterative pattern of phonemic variation became prominent, whereas phonological paraphasia and conduite d'approche were observed in the patient's overall speech. Therefore, the aphasia was characterized by the combination of conduction aphasia and neologistic jargon. At 27 months after symptom onset, the neologisms and iterative pattern of phonemic variation had disappeared, but a wide variety of phonological paraphasia and conduite d'approche persisted, clarifying the pathological features of the conduction aphasia experienced by this patient. The conduction theory (Kertesz et al., 1970) provides a convincing explanation for the mechanism of the onset of neologisms in the present case. Thus, we propose the existence of a symptomatic relationship between neologisms and phonological paraphasia.

Developmental conduction aphasia after neonatal stroke.

OBJECTIVE: Impairment of speech repetition following injury to the dorsal language stream is a feature of conduction aphasia, a well-described "disconnection syndrome" in adults. The impact of similar lesions sustained in infancy has not been established. METHODS: We compared language outcomes in term-born individuals with confirmed neonatal stroke (n = 30, age = 7-18 years, left-sided lesions in 21 cases) to matched controls (n = 40). Injury to the dorsal and/or ventral language streams was assessed using T1 - and T2 -weighted magnetic resonance imaging (MRI) and diffusion tractography. Language lateralization was determined using functional MRI. RESULTS: At the group level, left dorsal language stream injury was associated with selective speech repetition impairment for nonwords (p = 0.021) and sentences (p < 0.0001). The majority of children with significant repetition impairment had retained left hemisphere language representation, but right hemisphere dominance was correlated with minimal or absent repetition deficits. Post hoc analysis of the repetition-impaired group revealed additional language-associated deficits, but these were more subtle and variable. INTERPRETATION: We conclude that (1) despite the considerable plasticity of the infant brain, early dorsal language stream injury can result in specific and long-lasting problems with speech repetition that are similar to the syndrome of conduction aphasia seen in adults; and (2) language reorganization to the contralateral hemisphere has a protective effect. Ann Neurol 2018;83:664-675 Ann Neurol 2018;83:664-675.

Phonotactic processing deficit following left-hemisphere stroke.

The neural basis of speech processing is still a matter of great debate. Phonotactic knowledge-knowledge of the allowable sound combinations in a language-remains particularly understudied. The purpose of this study was to investigate the brain regions crucial to phonotactic knowledge in left-hemisphere stroke survivors. Results were compared to areas in which gray matter anatomy related to phonotactic knowledge in healthy controls. 44 patients with chronic left-hemisphere stroke, and 32 controls performed an English-likeness rating task on 60 auditory non-words of varying phonotactic regularities. They were asked to rate on a 1-5 scale, how close each non-word sounded to English. Patients' performance was compared to that of healthy controls, using mixed effects modeling. Multivariate lesion-symptom mapping and voxel-based morphometry were used to find the brain regions important for phonotactic processing in patients and controls respectively. The results showed that compared to controls, stroke survivors were less sensitive to phonotactic regularity differences. Lesion-symptom mapping demonstrated that a loss of sensitivity to phonotactic regularities was associated with lesions in left angular gyrus and posterior middle temporal gyrus. Voxel-based morphometry also revealed a positive correlation between gray matter density in left angular gyrus and sensitivity to phonotactic regularities in controls. We suggest that the angular gyrus is used to compare the incoming speech stream to internal predictions based on the frequency of sound sequences in the language derived from stored lexical representations in the posterior middle temporal gyrus.

Neuroanatomical correlates of the post-stroke aphasias studied with cerebral blood flow SPECT scanning.

BACKGROUND: Researchers are not in complete agreement over the extent to which specific language functions are subserved by certain brain areas. The purpose of this article was to determine neuroanatomical correlates of aphasia following cerebrovascular accident. MATERIAL/METHODS: The participants included 50 stroke patients with a single left-hemisphere lesion and residual mild to severe aphasia. Language, assessed by the Boston Diagnostic Aphasia Examination (BDAE), was affected to various degrees by a wide range of pathologies. Single-photon emission computed tomography (SPECT) images of the brain were acquired with 740 MBq (20 mCi) of Tc-99m-labeled ECD on a triple-headed gamma camera equipped with low-energy, high-resolution collimator. Correlation between reduced cerebral perfusion and the BDAE score was analyzed. RESULTS: The most prominent perfusion abnormalities in Broca's aphasia, as determined by the laterality index, were found in the frontal lobe, and to a lesser degree, the parietal lobe and striatum, whereas the most prominent deficits in Wernicke's aphasia were found in the left temporal and parietal areas. In global aphasia, SPECT images evidenced the most extensive damage throughout the perisylvian region of the left hemisphere. CONCLUSIONS: There is need for reinterpretation of the anatomical correlation of selected aphasic syndromes, especially classic Broca's and Wernicke's aphasias. The present study highlights the integrative role of some subcortical structures in language and speech functions. The results support the usefulness of regional cerebral blood flow SPECT imaging as a diagnostic aid in the post-stroke aphasias.

"Semantic" conduction aphasia from a posterior insular cortex infarction.

A unique infarction limited to the posterior insula and intrasylvian parietal opercular cortex produced a subtype of conduction aphasia, characterized by a predominance of semantic paraphasias. Temporal lobe hypoperfusion seen on hexamethylpropyleneamineoxime single-photon emission computed tomography in the absence of any signs of ischemia suggested that cortical diaschisis played a role in the emergence of this syndrome.