Gait Function after High-Intensity Focused Ultrasound Thalamotomy for Essential Tremor: Searching for Technique Optimization.

INTRODUCTION: Essential tremor (ET) is one of the most prevalent movement disorders in adults and may be highly disabling for some. Magnetic resonance image-guided high-intensity focused ultrasound (MRIgFUS) has been shown to control tremor efficaciously and with acceptable risk. To date, paresthesia and ataxia are the most common adverse effects (AE). Nevertheless, the impact of MRIgFUS thalamotomy on balance is not well established. METHODS: Thirty-two patients underwent MRIgFUS for ET and completed 6 months of follow-up. Tremor severity and functional disability were assessed using the Essential Tremor Rating Scale and the Quality of Life in Essential Tremor Questionnaire. The Berg Balance Scale (BBS) was applied to objectively measure balance status. RESULTS: All treatments were successful. The sonication target was 1-2 mm above the depth of the intercommissural line. Procedures lasted less the 2 h, with an average of 8 sonications per patient. Twenty-four patients were included in the tremor analysis. The hand tremor score was improved by 76% after 6 months of follow-up and 87% of patients self-reported marked improvement (≥75%). Disability scores showed marked improvement (78%), leading to a significant improvement in quality of life. At the final follow-up, 48% of the patients reported no side effects. When present, AE were generally transient and were considered mild in 96% of affected patients. Paresthesia and subjective feeling of unsteadiness were the most common persistent complaints (23% and 20%, respectively). Regarding objective ataxia, BBS scores remained stable throughout follow-up for most patients. Only 2 patients suffered a mild worsening of balance although no patients experienced moderate or severe ataxia. CONCLUSIONS: Subjective feeling of unsteadiness is one of the most frequent AE after MRIgFUS, although objective ataxia is infrequent and mild. Selecting the most appropriate lesion location and procedural parameters should increase treatment benefits while reducing side effects.

Anatomical and functional differences between the Paced Auditory Serial Addition Test and the Symbol Digit Modalities Test.

The Paced Auditory Serial Addition Test (PASAT) and the Symbol Digit Modalities Test (SDMT) are generally used to detect cognitive impairments in multiple sclerosis patients. Although both seem to be sensitive to the slow information-processing speed, some results suggest that they do not involve the same cognitive functions. The aim of the present study is to observe possible differences between these tasks to help understand their utility to cognitive assessment. A total of 17 participants were recruited for the study and completed a block-design version of each task. Comparisons between tasks were calculated using an analysis of variance (ANOVA; p < .05, familywise error, FWE, corrected). We observed activations in the left frontal and parietal areas during both tasks; however, the PASAT activated more frontal areas than did the SDMT. These tasks require an efficient transfer of information among large areas. Moreover, the PASAT requires more executive functions to be executed.

A comparison of brain activation patterns during covert and overt paced auditory serial addition test tasks.

The Paced Auditory Serial Addition test (PASAT) is a sensitive task for evaluating cognitive impairment in patients with diffuse brain disorders, such as multiple sclerosis patients. Brain areas involved in this task have been investigated in diverse fMRI studies using different methodologies to control the subjects' responses during scanning. Here, we examined the possible differences between overt and covert responses during the PASAT task in 13 volunteers. Results showed similar activations in parietal and frontal brain areas during both versions of the task. The contrast between the two conditions (overt and covert) indicated that differences in these two methodologies were minimal. Unlike the covert condition, the overt version of the task obtained significant activations in the left superior and inferior frontal gyrus, bilateral occipital cortex, caudate nucleus and cerebellum. As expected, no significant overactivations were observed in the covert when compared with the overt condition. Discussion focuses on the lower cost of using verbal responses to monitor performance during the PASAT task, which might be generalisable to other frontal lobe tasks requiring discrete responses.

Reading cinnamon activates olfactory brain regions.

Some words immediately and automatically remind us of odours, smells and scents, whereas other language items do not evoke such associations. This study investigated, for the first time, the abstract linking of linguistic and odour information using modern neuroimaging techniques (functional MRI). Subjects passively read odour-related words ('garlic', 'cinnamon', 'jasmine') and neutral language items. The odour-related terms elicited activation in the primary olfactory cortex, which include the piriform cortex and the amygdala. Our results suggest the activation of widely distributed cortical cell assemblies in the processing of olfactory words. These distributed neuron populations extend into language areas but also reach some parts of the olfactory system. These distributed neural systems may be the basis of the processing of language elements, their related conceptual and semantic information and the associated sensory information.

Selective alteration of native, but not second language articulation in a patient with foreign accent syndrome.

The present study deals with a right-handed female polyglot suffering from a Foreign Accent Syndrome (FAS) which affects her native language (L1), but not her other languages learnt since the age of 12. She had a small infarct in the left corona radiata as the result of a carotid occlusion. Her L1 was Spanish, but she also had a good command of French, English and Catalan (L2). Aphasia tests did not reveal any other significant alteration in any language. Analyses of pre-morbid and post-morbid voice recordings revealed that FAS affected Spanish dramatically, but no important changes were observed for French. Results were interpreted as showing that different brain areas control articulation of L1 and L2 learnt after a critical period.