Background and Purpose-Studies on adult stroke patients have demonstrated functional changes in cortical excitability, metabolic rate, or blood flow after motor therapy, measures that can fluctuate rapidly over time. This study evaluated whether evidence could also be found for structural brain changes during an efficacious rehabilitation program. Methods-Chronic stroke patients were randomly assigned to receive either constraint-induced movement therapy (nϭ16) or a comparison therapy (nϭ20). Longitudinal voxel-based morphometry was performed on structural MRI scans obtained immediately before and after patients received therapy. Results-The group receiving constraint-induced movement therapy exhibited far greater improvement in use of the more affected arm in the life situation than the comparison therapy group. Structural brain changes paralleled these improvements in spontaneous use of the more impaired arm for activities of daily living. There were profuse increases in gray matter in sensory and motor areas both contralateral and ipsilateral to the affected arm that were bilaterally symmetrical, as well as bilaterally in the hippocampus. In contrast, the comparison therapy group failed to show gray matter increases. Importantly, the magnitude of the observed gray matter increases was significantly correlated with amount of improvement in real-world arm use. Conclusions-These findings suggest that a previously overlooked type of brain plasticity, structural remodeling of the human brain, is harnessed by constraint-induced movement therapy for a condition once thought to be refractory to treatment: motor deficit in chronic stroke patients. Key Words: constraint-induced movement therapy Ⅲ hemiplegia Ⅲ imaging Ⅲ motor activity Ⅲ MRI Ⅲ stroke rehabilitation Ⅲ voxel-based morphometry M erzenich et al 1 and other investigators 2 showed in animals that altering behaviorally relevant afferent input to the central nervous system can produce plastic changes in the function and organization of the brain. Sustained increased use of a body part by an animal leads to an increase in the brain's cortical representation of that body part, 3 whereas decreased input reduces the representational zone of that body part, as occurs after amputation of a digit 1 or somatosensory deafferentation of an entire forelimb in monkeys. 4 Similar phenomena have been demonstrated in humans after both increased use 5 and decreased use resulting from upper extremity amputation 6 or stroke 7 using functional imaging or mapping techniques.A neurorehabilitation technique termed Constraint-Induced Movement therapy (CI therapy) was developed in this laboratory from basic research with monkeys. 8 This treatment has been shown to substantially increase the amount of use of an affected upper extremity after stroke 9 -12 and also greatly alter the size of the regional brain activity or activation pattern associated with the more affected arm. 7,[13][14][15] Until now, neuroanatomical evaluations of treatment changes in humans have relied solely on funct...
Tinnitus is an auditory perception in the absence of any external sound source. It has been suggested that tinnitus is related to enhanced synchronization of neuronal activity in the auditory cortex. Usually a hearing damage can be identified suggesting auditory deprivation to central auditory regions to be fundamental for neurophysiological processes related to tinnitus. Until now, human research has been conducted on patients with chronic tinnitus (>6 months). However, neuronal activity accompanying auditory deprivation and putatively tinnitus may not remain constant over time, making it difficult to directly relate outcomes of current animal studies (acute tinnitus) to chronic tinnitus in humans, and vice versa. We investigated 14 amateur rock musicians who frequently reported a short-term tinnitus immediately after band practice. Magnetoencephalographic resting-state recordings, audiometry and tinnitus testing were performed at two separate occasions: with and without previous exposure to loud music. Analyses revealed that transient tinnitus was accompanied by temporary hearing loss in both ears and increased gamma activity in the right auditory cortex in 13 out of 14 cases. Additionally, tinnitus frequency was strongly correlated to hearing loss. Analogous to animal studies, our results show for the first time in humans that noise trauma leads rapidly to increased neuronal synchrony in the auditory cortex. Importantly, the strongly right-lateralized effect implies that it does not reflect tinnitus percept per se. This could rather have been triggered by greater discontinuities of hearing loss at high frequencies that were particularly pronounced in the left ear.
Prelingually deafened children with cochlear implants stand a good chance of developing satisfactory speech performance. Nevertheless, their eventual language performance is highly variable and not fully explainable by the duration of deafness and hearing experience. In this study, two groups of cochlear implant users (CI groups) with very good basic hearing abilities but non-overlapping speech performance (very good or very bad speech performance) were matched according to hearing age and age at implantation. We assessed whether these CI groups differed with regard to their phoneme discrimination ability and auditory sensory memory capacity, as suggested by earlier studies. These functions were measured behaviorally and with the Mismatch Negativity (MMN). Phoneme discrimination ability was comparable in the CI group of good performers and matched healthy controls, which were both better than the bad performers. Source analyses revealed larger MMN activity (155–225 ms) in good than in bad performers, which was generated in the frontal cortex and positively correlated with measures of working memory. For the bad performers, this was followed by an increased activation of left temporal regions from 225 to 250 ms with a focus on the auditory cortex. These results indicate that the two CI groups developed different auditory speech processing strategies and stress the role of phonological functions of auditory sensory memory and the prefrontal cortex in positively developing speech perception and production.
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