RESUMO
BACKGROUND: Pallidal Deep Brain Stimulation (GPi-DBS) is an efficient treatment for primary dystonia. We investigated stimulation-induced dysarthria, which is the most frequent side-effect of GPi-DBS. METHODS: Speech was recorded while reading a standard text, and performing rapid syllable repetitions ON and OFF DBS in ten dystonia patients (6 men; 3 cervical, 4 segmental, 3 generalized, unselected for DBS-related speech impairments). Speech and articulation rate, pauses, and syllable repetition rates were extracted via acoustic analysis. Locations of active stimulation contacts and volumes of tissue activated (VTA) were calculated. RESULTS: The number of pauses increased significantly ON vs. OFF stimulation (Wilcoxon test, p < 0.05). More posteriorly localized active contacts were associated with slower syllable repetition (Pearson correlation, p < 0.05). VTA size did not correlate with any measure of dysarthria. CONCLUSION: Using quantitative acoustic signal analysis, this study demonstrates that GPi-DBS alters motor aspects of speech. Both inadvertent stimulation of parts of the internal capsule, or interference with GPi function and outflow are possible causes. Understanding causes of GPi-DBS-induced speech changes can improve DBS programming.
Assuntos
Estimulação Encefálica Profunda/efeitos adversos , Disartria/etiologia , Globo Pálido/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Disartria/diagnóstico por imagem , Distonia/diagnóstico por imagem , Distonia/terapia , Eletrodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Resultado do Tratamento , Adulto JovemRESUMO
Speech recognition in a multi-talker situation poses high demands on attentional and other central resources. This study examines the relationship between age, cognition and speech recognition in tasks that require selective or divided attention in a multi-talker setting. Two groups of normal-hearing adults (one younger and one older group) were asked to repeat utterances from either one or two concurrent speakers. Cognitive abilities were then inspected by neuropsychological tests. Speech recognition scores approached its ceiling and did not significantly differ between age groups for tasks that demanded selective attention. However, when divided attention was required, performance in older listeners was reduced as compared to the younger group. When selective attention was required, speech recognition was strongly related to working memory skills, as determined by a regression model. In comparison, speech recognition for tests requiring divided attention could be more strongly determined by neuropsychological probes of fluid intelligence. The findings of this study indicate that - apart from hearing impairment - cognitive aspects account for the typical difficulties of older listeners in a multi-speaker setting. Our results are discussed in the context of evidence showing that frontal lobe functions in terms of working memory and fluid intelligence generally decline with age.
Assuntos
Atenção , Cognição , Reconhecimento Fisiológico de Modelo , Percepção da Fala , Adolescente , Adulto , Idoso , Envelhecimento/psicologia , Feminino , Humanos , Masculino , Memória de Curto Prazo , Pessoa de Meia-Idade , Testes Neuropsicológicos , Adulto JovemRESUMO
The occurrence of cognitive decline in amyotrophic lateral sclerosis (ALS), especially in the form of frontotemporal dementia (FTD), has been described previously. Recent molecular biology and histopathology data suggest that both ALS and FTD may share common pathological pathways and may present two phenotypes of the same proteinopathy. The underlying pathophysiological mechanism may be defective RNA- and DNA-modulation, mediated by the proteins TDP43 and FUS.âThese findings are suggestive of a new disease category of TDP43-proteinopathies, which include ALS, FTD and overlap syndromes. While about half of the FTD cases are associated with TDP43-deposits, tau is found in the other half. A significant clinical overlap to other tauopathies exists here as well, for instance with corticobasal degeneration. In this paper, we present a case report and review the clinical spectrum and current pathogenetic concepts of FTD.
Assuntos
Esclerose Lateral Amiotrófica/complicações , Esclerose Lateral Amiotrófica/psicologia , Demência Frontotemporal/complicações , Demência Frontotemporal/psicologia , Esclerose Lateral Amiotrófica/tratamento farmacológico , Esclerose Lateral Amiotrófica/genética , Comportamento , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/psicologia , Proteínas de Ligação a DNA , Eletroencefalografia , Demência Frontotemporal/genética , Demência Frontotemporal/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tomografia por Emissão de Pósitrons , Proteínas tau/genética , Proteínas tau/metabolismoRESUMO
Recent work has demonstrated that overt reading influences the excitability of the language-dominant hand motor cortex. However, this effect was related to speech output, whereas results on silent reading have been inconsistent, and have not allowed for systematic investigation of the different stages of word recognition. To investigate a possible modulation of the cortical excitability mediating hand movements through different stages of covert reading, motor evoked potentials (MEP) from hand muscles in right-handed subjects were recorded. We showed a significant increase of the excitability of the hand motor cortex of the dominant hemisphere during late stages of covert word reading, whereas processing of abstract shapes had no effect and covert articulation induced a decrease in hand motor cortex excitability. There was no significant change of MEP amplitudes during earlier stages of covert reading in the dominant hemisphere or in the non-dominant hemisphere. Our results demonstrate a functional connection between cortical networks mediating linguistic processing and hand movements without concurrent activation of the motor cortex through overt articulation at late stages of word reading, which have been shown to involve converging activation of classic left frontal language regions. We speculate that the effect reported here is related to a cortical network mediating gestures which are a part of verbal communication. This supports recent theories on language evolution which postulate that language emerged through manual gestures.
Assuntos
Lateralidade Funcional , Mãos/inervação , Idioma , Córtex Motor/fisiologia , Movimento , Reconhecimento Visual de Modelos , Potencial Evocado Motor , Mãos/fisiologia , Humanos , Masculino , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Tempo de Reação , LeituraRESUMO
Although language functions are, in general, attributed to the left hemisphere, it is still a matter of debate to what extent the cognitive functions underlying the processing of music are lateralized in the human brain. To investigate hemispheric specialization we evaluated the effect of different overt musical and linguistic tasks on the excitability of both left and right hand motor cortices using transcranial magnetic stimulation (TMS). Task-dependent changes of the size of the TMS-elicited motor evoked potentials were recorded in 12 right-handed, musically naive subjects during and after overt speech, singing and humming, i.e. the production of melody without word articulation. The articulation of meaningless syllables served as control condition. We found reciprocal lateralized effects of overt speech and musical tasks on motor cortex excitability. During overt speech, the corticospinal projection of the left (i.e. dominant) hemisphere to the right hand was facilitated. In contrast, excitability of the right motor cortex increased during both overt singing and humming, whereas no effect was observed on the left hemisphere. Although the traditional concept of hemispheric lateralization of music has been challenged by recent neuroimaging studies, our findings demonstrate that right-hemisphere preponderance of music is nevertheless present. We discuss our results in terms of the recent concepts on evolution of language and gesture, which hypothesize that cerebral networks mediating hand movement and those subserving language processing are functionally linked. TMS may constitute a useful tool to further investigate the relationship between cortical representations of motor functions, music and language using comparative approaches.
Assuntos
Mãos/fisiologia , Idioma , Córtex Motor/fisiologia , Música , Rede Nervosa/fisiologia , Estimulação Magnética Transcraniana , Adulto , Potencial Evocado Motor/fisiologia , Lateralidade Funcional , Humanos , Masculino , Análise e Desempenho de TarefasRESUMO
Whereas it is widely accepted that the parietal cortex is crucial for visual attention, the role of the temporal cortex and the temporo-parietal junction (TPJ) is less clear. There are clinical reports of patients with lesions in different posterior temporal areas which exhibit contralateral visual neglect but this syndrome seems to be less frequent than in patients with parietal lesions. In a previous study, we could show that single-pulse transcranial magnetic stimulation (TMS) over the right inferior parietal cortex is capable to induce both neglect-like and extinction-like impairments of performance in normal subjects. In the present study, we used this method to examine the functional role of the superior temporal gyrus (STG) and the TPJ of the right hemisphere for visuo-spatial attention. Healthy volunteers were asked to detect small dots appearing for 40 ms unilaterally on right or left side or bilaterally on a computer screen. TMS was applied over the TPJ or STG. TMS over the TPJ induced an extinction-like behavioral pattern to the contralateral hemifield. TMS over the STG had no effect. The results demonstrate a functional involvement of the TPJ in visuo-attentional processing of competing stimuli in both hemifields. This region is part of the cortical network mediating stimulus-driven attention which is relevant for processing of competing stimuli.
Assuntos
Lobo Frontal/fisiopatologia , Lateralidade Funcional/fisiologia , Lobo Parietal/fisiopatologia , Transtornos da Percepção/etiologia , Estimulação Magnética Transcraniana/efeitos adversos , Adulto , Atenção/fisiologia , Feminino , Humanos , Masculino , Estimulação Luminosa/métodos , Percepção Espacial/fisiologiaRESUMO
Previous data indicate that in healthy subjects, there is a connectivity between cortical areas for hand movement and language on the left hemisphere. This link is possibly mediated by the so-called mirror neuron system. The present study investigated the functional relationship between linguistic and hand movement processing in patients who were recovering from post-stroke aphasia. The excitability of the right- and left-hand motor cortex during language production in patients who were recovering from post-stroke aphasia and age-matched controls was investigated. As control, phonation was investigated. Hand motor cortex excitability was assessed with Motor Evoked Potentials which were elicited by Transcranial Magnetic Stimulation (TMS). In patients, reading aloud enhanced the excitability of the right hemispheric hand motor cortex, whereas phonation had no effect on hand motor cortex excitability. In the control group, an increased excitability of the left hemispheric hand motor system was found during reading aloud in accordance with previous data. The present data suggest a functional connectivity between regions mediating hand movements and reading. This may indicate that the right hemisphere participates in language processing as far as involved in single word reading in patients recovering from aphasia. The coactivation between cerebral representations of hand movements and language may be used therapeutically for aphasia rehabilitation.
Assuntos
Afasia/fisiopatologia , Mãos/inervação , Idioma , Córtex Motor/fisiopatologia , Desempenho Psicomotor/fisiologia , Recuperação de Função Fisiológica/fisiologia , Adulto , Análise de Variância , Afasia/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Magnética Transcraniana/métodosRESUMO
INTRODUCTION: The aim of the present investigation was to elucidate in a large consecutive patient cohort whether the level of training has an effect on the number of microemboli detected by diffusion-weighted imaging (DWI) and which additional risk factors can be identified. METHODS: A total of 107 consecutive patients in whom a diagnostic cerebral angiography had been performed were prospectively investigated with DWI; 51 angiographies were performed by experienced neuroradiologists, 56 by neuroradiologists in training. RESULTS: In 12 patients (11.1%), a total of 17 new lesions without any clinically overt neurological symptoms were identified. Of these, 12 patients, 11 (91.7%) with 16 lesions were investigated by junior neuroradiologists. In 11 of 12 patients with DWI abnormalities (91.7%), risk factors could be identified (atherosclerotic vessel wall disease, vasculitis, hypercoagulable states). Experienced neuroradiologists performed 21 of 48 angiographies (43.8%) on patients with the above-mentioned risk factors, whereas junior neuroradiologists performed 27 angiographies in this subgroup (46.2%). The rate of diffusion abnormalities in patients with risk factors was 11/48 (22.9%) - considerably higher than in patients without risk factors (1/59; 1.7%). CONCLUSION: The level of experience and the nature of the underlying disease are predictors of the occurrence of cerebral ischemic events following neuroangiography. Alternative diagnostic modalities should be employed in patients who are investigated for diseases with the highest risk of angiographic complications (i.e., vasculitis, and arteriosclerotic vessel wall disease). If diagnostic angiography remains necessary in these patients, the highest level of practitioner training is necessary to ensure good patient outcome.
Assuntos
Angiografia Cerebral , Competência Clínica , Imagem de Difusão por Ressonância Magnética , Embolia Intracraniana/diagnóstico por imagem , Adolescente , Adulto , Idoso , Isquemia Encefálica/etiologia , Angiografia Cerebral/efeitos adversos , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Fatores de RiscoRESUMO
The cerebral activation pattern due to acupuncture is not completely understood. Although the effect of acupuncture on cerebral haemodynamics has been studied, no previous report has focused on different puncture and stimulation methods. We used functional MRI (fMRI) in 15 healthy subjects to investigate cortical activation during stimulation of two real acupoints (Liv3 and G40) and one sham point, needled in a random and, for the subjects, blinded order employing rotating and non-rotating methods, using a blocked paradigm on a 1.5 tesla imager. Compared to the non-rotating stimulation method, during rotating stimulation of the real acupoints, we observed an increase in activation in both secondary somatosensory cortical areas, frontal areas, the right side of the thalamus and the left side of the cerebellum; no such effects of the needling technique were seen while stimulating the sham point. The observation that rotating the needle strengthened the effects of acupuncture only at real acupoints suggests that, as claimed in Chinese traditional medicine, stimulation of these acupoints has a specific effect on cortical neuronal activity, absent with sham acupoints. These specific cerebral activation patterns might explain the therapeutic effects of acupuncture in certain subjects.
Assuntos
Terapia por Acupuntura/métodos , Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Adulto , Feminino , Pé , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Agulhas , Valores de Referência , Rotação , Método Simples-CegoRESUMO
Reading of musical notes and playing piano is a very complex motor task which requires years of practice. In addition to motor skills, rapid and effective visuomotor transformation as well as processing of the different components of music like pitch, rhythm and musical texture are involved. The aim of the present study was the investigation of the cortical network which mediates music performance compared to music imagery in 12 music academy students playing the right hand part of a Bartok piece using functional magnetic resonance imaging (fMRI). In both conditions, fMRI activations of a bilateral frontoparietal network comprising the premotor areas, the precuneus and the medial part of Brodmann Area 40 were found. During music performance but not during imagery the contralateral primary motor cortex and posterior parietal cortex (PPC) bilaterally was active. This reflects the role of primary motor cortex for motor execution but not imagery and the higher visuomotor integration requirements during music performance compared to simulation. The notion that the same areas are involved in visuomotor transformation/motor planning and music processing emphasizes the multimodal properties of cortical areas involved in music and motor imagery in musicians.
Assuntos
Encéfalo/fisiologia , Imaginação/fisiologia , Imageamento por Ressonância Magnética/métodos , Música , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Humanos , Masculino , Rede Nervosa/fisiologiaRESUMO
The clinical and magnetic resonance (MR) features of hypertrophic olivary degeneration are described, along with a rare but treatable cause of this entity-pontine cavernous haemangioma. Hypertrophic olivary degeneration occurs after focal lesions to the dentato-rubro-olivary pathway, typically following a pontine haemorrhage involving the ipsilateral central tegmental tract, the contralateral superior cerebellar peduncle, or the dentate nucleus. Clinically, there is palatal myoclonus and an uncontrollable tremor, presumably caused by loss of inhibitory control. On MR imaging, hypertrophic olivary degeneration is characterised by a non-enhancing T1 isointense, T2 hyperintense enlargement confined to the olivary nucleus. Typically, haemorrhages following a hypertensive crisis are responsible for hypertrophic olivary degeneration. However, in the three reported cases, imaging findings within the former bleeding cavity suggested a cavernous haemangioma as the source of the haemorrhage.
Assuntos
Hemorragia Cerebral/etiologia , Hemorragia Cerebral/patologia , Hemangioma Cavernoso do Sistema Nervoso Central/complicações , Hemangioma Cavernoso do Sistema Nervoso Central/patologia , Hipertensão/complicações , Hipertensão/diagnóstico , Degeneração Neural/patologia , Núcleo Olivar/patologia , Ponte/patologia , Diagnóstico Diferencial , Seguimentos , Humanos , Hipertrofia/etiologia , Hipertrofia/patologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Fatores de TempoRESUMO
Our aim was to determine whether age, sex, the degree of weakness, anticonvulsants, the histology of the underlying lesion(s), the presence of oedema or the distance of the lesion from the motor region have an impact on the blood oxygenation level-dependent (BOLD) signal strength and therefore on the validity of functional MRI (fMRI). We studied 98 patients with masses near the central region imaged for surgical planning at 1.5 tesla, employing a BOLD sequence during a motor task. We calculated percentage signal change in the primary motor cortex between rest and activation and carried out multiple linear regression to examine the impact of the above factors on signal strength. Using a stepwise analysis strategy, the distance of the lesion from the motor region had the strongest influence (r=0.653, P<0.001). The factor with largest uncorrelated additional impact on signal change was the presence of oedema. Both predictors together formed a highly significant multiple r=0.739 ( P<0.001). No other predictive factor was identified (all P>0.20). Disturbances of cerebral blood flow and metabolism induced by the tumour were presumed to be the causes of a decrease in signal in the adjacent cortex.
Assuntos
Imageamento por Ressonância Magnética , Processamento de Sinais Assistido por Computador , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/irrigação sanguínea , Córtex Motor/patologia , Paresia/patologia , Valor Preditivo dos Testes , Índice de Gravidade de DoençaRESUMO
OBJECTIVE: Simple reaction time (RT) can be influenced by transcranial magnetic stimulation (TMS) to the motor cortex. Since TMS differentially affects RT of ipsilateral and contralateral muscles a combined RT and TMS investigation sheds light on cortical motor control of bimanual movements. METHODS: Ten normal subjects and one subject with congenital mirror movements (MM) were investigated with a RT paradigm in which they had to move one or both hands in response to a visual go-signal. Suprathreshold TMS was applied to the motor cortex ipsilateral or contralateral to the moving hand at various interstimulus intervals (ISIs) after presentation of the go-signal. EMG recordings from the thenar muscles of both hands were used to determine the RT. RESULTS: TMS applied to the ipsilateral motor cortex shortened RT when TMS was delivered simultaneously with the go-signal. With increasing ISI between TMS and go-signal the RT was progressively delayed. This delay was more pronounced if TMS was applied contralateral to the moving hand. When normal subjects performed bimanual movements the TMS-induced changes in RT were essentially the same as if they had used the hand in an unimanual task. In the subject with MM, TMS given at the time of the go-signal facilitated both the voluntary and the MM. With increasing ISI, however, RT for voluntary movements and MM increased in parallel. CONCLUSIONS: Ipsilateral TMS affects the timing of hand movements to the same extent regardless of whether the hand is engaged in an unimanual or a bimanual movement. It can be concluded, therefore, that in normal subjects simple bimanual movements are controlled by each motor cortex independently. The results obtained in the subject with MM are consistent with the hypothesis that mirror movements originate from uncrossed corticospinal fibres. The alternative hypothesis that a deficit in transcallosal inhibition leads to MM in the contralateral motor cortex is not compatible with the presented data, because TMS applied to the motor cortex ipsilateral to a voluntary moved hand affected voluntary movements and MM to the same extent.