rTMS treatments combined with speech training for a conduction aphasia patient: A case report with MRI study

RATIONALE

To date, little is known regarding the neural mechanisms of the functional recovery of language after repetitive transcranial magnetic stimulation (rTMS) in aphasia. Our aim was to investigate the mechanism that underlies rTMS and speech training in a case report.

PATIENT CONCERNS AND DIAGNOSES

We report the case of a 39-year-old woman who was initially diagnosed with conduction aphasia following a left hemisphere stroke.

INTERVENTIONS

The rTMS location comprised the left Broca area, and a frequency of 5 Hz for 20 min/d for 10 days during a 2-week period was used. She had received speech rehabilitation training 1 month after stroke. Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging were used to investigate the functional and microstructural changes before and after rTMS treatment.

OUTCOMES

The results demonstrated that the Western Aphasia Battery scores significantly improved for language ability at 2 weeks post-treatment, and the gains were steadily increased at 2.5 months post-treatment. The fMRI results indicated a more focused activation pattern and showed significant activation in the left dominant hemisphere relative to the right hemisphere, especially in the perilesional areas, post-treatment during 2 language tasks compared with pretreatment. Moreover, the fractional anisotropy increased in the left superior temporal gyrus, which comprises an important area that is involved in language processing.

LESSONS

Our findings suggest that rTMS combined with speech training improved the speech-language ability of this chronic conduction aphasia patient and enhanced the cerebral functional and microstructural reorganization.

Conduction aphasia, sensory-motor integration, and phonological short-term memory - an aggregate analysis of lesion and fMRI data

Conduction aphasia is a language disorder characterized by frequent speech errors, impaired verbatim repetition, a deficit in phonological short-term memory, and naming difficulties in the presence of otherwise fluent and grammatical speech output. While traditional models of conduction aphasia have typically implicated white matter pathways, recent advances in lesions reconstruction methodology applied to groups of patients have implicated left temporoparietal zones. Parallel work using functional magnetic resonance imaging (fMRI) has pinpointed a region in the posterior most portion of the left planum temporale, area Spt, which is critical for phonological working memory. Here we show that the region of maximal lesion overlap in a sample of 14 patients with conduction aphasia perfectly circumscribes area Spt, as defined in an aggregate fMRI analysis of 105 subjects performing a phonological working memory task. We provide a review of the evidence supporting the idea that Spt is an interface site for the integration of sensory and vocal tract-related motor representations of complex sound sequences, such as speech and music and show how the symptoms of conduction aphasia can be explained by damage to this system.

What can iconic gestures tell us about the language system? A case of conduction aphasia

BACKGROUND

Speech and language therapists rarely analyse iconic gesture when assessing a client with aphasia, despite a growing body of research suggesting that language and gesture are part of either the same system or two highly integrated systems. This may be because there has been limited research that has systematically analysed iconic gesture production by people with aphasia.

AIMS

The aim was to determine whether the gesture production of a participant with conduction aphasia was able to provide information about her language system.

METHODS & PROCEDURES

The iconic gestures produced by a participant with conduction aphasia (LT) and five control participants produced during the retelling of a cartoon were analysed. In particular, the iconic gestures produced during lexical retrieval difficulties (co-tip-of-the-tongue (co-TOT) gestures) were compared with the iconic gestures produced during fluent speech (co-speech gestures).

OUTCOMES & RESULTS

It was found that LT produced 57 co-speech gestures that were similar in form to the co-speech gestures produced by the control participants (mean = 34.2, standard deviation (SD) = 22.2). LT also produced an additional eleven co-TOT gestures that were unlike her co-speech gestures and unlike the co-speech gestures produced by the control participants. While the co-speech gestures depicted events, the co-TOT gestures depicted 'things' (for example, objects and animals). Furthermore, all but one of the co-TOT gestures produced by LT was classified as a shape-outline gesture, whereas co-speech gestures were rarely classified as shape-outline gestures. LT also produced a new type of gesture that has not previously been described in the literature: a homophone gesture. This co-TOT homophone gesture depicted the homophone of the target word. The iconic gestures produced by LT suggest that she had an intact semantic system but had difficulties with phonological encoding, consistent with a diagnosis of conduction aphasia. This raises the possibility that iconic gesture production can provide evidence about the level of breakdown in the language system.

CONCLUSIONS & IMPLICATIONS

A larger study exploring the gestures produced by participants with aphasia is required. The research also highlights the importance of including gesture assessments in SLT's work with adults with acquired language disorder.

[Case of conduction aphasia due to right hemispheric lesion]

We report the case of conduction aphasia due to injury of the right hemisphere of the brain. The patient was a right-handed male in his fifties with moyamoya disease. T2-weighted MRI showed an extensive high intensity area in the right temporal-parietal-occipital lobes. In the case of language-related symptoms, comprehension was preserved, but phonemic paraphasias were frequent, and kana paragraphias were also observed. Despite the extensive injury of the right hemisphere, these language-related symptoms were consistent with the clinical features of conduction aphasia. Therefore, this patient was diagnosed with atypical crossed aphasia. Improvement in the phonemic paraphasia differed between words and nonsense words, suggesting that the improvement was dependent on the level of meaning of the words.

Conduction aphasia as a function of the dominant posterior perisylvian cortex

✓ Assessment of eloquent functions during brain mapping usually relies on testing reading, speech, and comprehension to uncover transient deficits during electrical stimulation. These tests stem from findings predicted by the Geschwind–Wernicke hypothesis of receptive and expressive cortices connected by white matter tracts. Later work, however, has emphasized cortical mechanisms of language function. The authors report two cases that demonstrate that conduction aphasia is cortically mediated and can be inadequately assessed if not specifically evaluated during brain mapping.

To determine the distribution of language on the dominant cortex, electrical cortical stimulation was performed in two cases by using implanted subdural electrodes during brain mapping before epilepsy surgery. A transient isolated deficit in repetition of language was reported during stimulation of the posterior portion of the dominant superior temporal gyrus in one patient and during stimulation of the supramarginal gyrus in the other patient.

These cases demonstrate a localization of language repetition to the posterior perisylvian cortex. Brain mapping of this region should include assessment of verbal repetition to avoid potential deficits resembling conduction aphasia.

Linguistic and neuropsychological deficits in crossed conduction aphasia. Report of three cases

This study describes the linguistic and neuropsychological findings in three right-handed patients with crossed conduction aphasia. Despite the location of the lesion in the right hemisphere, all patients displayed a combination of linguistic deficits typically found in conduction aphasia following analogous damage to the left hemisphere. Associated cognitive deficits varied across the three patients. In addition, all cases showed deficits classically attributed to non-dominant hemisphere damage (visuoperceptual deficits and reduced figural memory). As a result, lesion-behaviour relationships in our study sample indicate both dominant and non-dominant qualities of the right hemisphere.

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.

[A case of conduction aphasia due to small infarction in the left parietal lobe]

This is a report on the patient with conduction aphAsia due to small infarction in the left parietal lobe. The patient is a right-handed man aged 74, who developed a speech disorder and mild paralysis of the right hand on November 13. 1996. A CT scan showed a small low-density in the supramarginal gyrus of the left parietal lobe. Standard Language Test of aphasia (SLTA) conducted at five days after admission to the hospital showed preserved auditory comprehension and phonemic para-aphasia symptoms with respect to volitional speech, naming, reading aloud and repetition. Frequent self-correction was also observed while repetition was not remarkably impaired. A test at three months after the onset revealed generally fluent speech, while there still remained occasional phonemic para-aphasia and self-correction for the speech disruption. Three years and four months later, most of the aphasic syndromes disappeared, although the patient claimed he still had difficulty in speaking. This case suggests that conduction aphasia can be caused by a lesion, though small, located in arcuate fibers of the cerebrum. The characteristics are phonemic para-aphasia with respect to general speech functions as well as self-correction toward target words. The indicated that lesions in the pathway connecting Broca's area and Wernicke's area causes difficulties in selecting accurate phonemes due to a malfunctioning interface between the two areas.

Primary progressive aphasia presenting as conduction aphasia

We report a case of a woman with primary progressive aphasia (PPA) who presented with conduction aphasia. A 60-year-old, right-handed, Japanese female suffering from progressive aphasia had difficulty in repeating words and phrases. She displayed phonemic paraphasias but had preserved comprehension and had no cognitive or behavior disorder for more than 6 years after the onset of the condition. She was able to continue to work successfully and to perform all her normal daily activities. T1-weighted magnetic resonance imaging revealed minute dilatation of the left inferior horn and sulci in the left hemisphere, and positron emission tomography revealed mild hypometabolism in the left supramarginal gyrus and its surrounding areas. Therefore, she was diagnosed as suffering from PPA presenting as conduction aphasia. We believe that the progressive conduction aphasia of the patient belongs to one of the fluent forms of PPA, and the ability to continue normal work along with the clinical portrayal of preserved memory and cognition skills may be features of a form of PPA presenting as conduction aphasia.

"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.