Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 24
Filter
1.
J Fluency Disord ; 38(1): 14-29, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23540910

ABSTRACT

UNLABELLED: This study explored the impact of the stuttering disorder on perceived quality of life, with emphasis on the individual's relationship with their partner or spouse. Specifically, the purposes were: (a) to investigate what personal experiences and themes exist for both members of a couple dyad when one member of the couple stutters and (b) to examine whether the partners have different experiences with respect to the impact of stuttering on their lives. A mixed method research design was used. Participant dyads (adults who stutter and their fluent life partner) each completed one semi-structured qualitative interview and two questionnaires: the Overall Assessment of Speakers' Experience of Stuttering (OASES), and the Medical Short Form 36 (SF-36). Interviews were analysed qualitatively and significant themes evaluated. Quantitative results of the OASES and SF-36 were analysed, and scores correlated to determine the strength of any clinically significant relationships. Results indicated that people who stutter and their fluent partners reported similar experiences in reactions to stuttering and perceived difficulties in communication. However, no relationship was seen between the two groups in perceived impact on quality of life. Qualitative results indicated that the participants shared life experiences including reactions to stuttering, treatment undertaken and support. Such findings lend support to a broad-based clinical programme for adults who stutter that includes the fluent partner as an agent of change in their treatment. Findings also support the utilisation of qualitative and quantitative research techniques to elucidate relevant psychosocial life themes and experiences for those who live with a stutter. EDUCATIONAL OBJECTIVES: The reader will be able to: (a) identify the life themes associated with having a partner who stutters; (b) identify the perceived impact of stuttering for adults who stutter compared to their partners; and (c) discuss the clinical implications of the results with regards to working with adults who stutter.


Subject(s)
Interpersonal Relations , Quality of Life , Spouses/psychology , Stuttering/psychology , Adult , Female , Humans , Interview, Psychological , Male , Middle Aged , Qualitative Research , Surveys and Questionnaires
2.
J Fluency Disord ; 37(4): 289-99, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23218212

ABSTRACT

UNLABELLED: The aim of the present study was to assess the effectiveness of an Acceptance and Commitment Therapy group intervention program for adults who stutter (N=20). The program consisted of 2-h therapeutic sessions conducted weekly for eight consecutive weeks. It was an integrated program designed to improve: (a) psychosocial functioning, (b) readiness for therapy and change, (c) utilisation of mindfulness skills and psychological flexibility, and (d) frequency of stuttering. The findings provide innovative evidence for Acceptance and Commitment Therapy as an effective intervention with statistically significant improvements in psychosocial functioning, preparation for change and therapy, utilisation of mindfulness skills, and overall speech fluency. Follow-up data collected at three months post-treatment revealed that therapeutic gains were successfully maintained over time. These findings enhance the understanding of the impact of stuttering on psychological wellbeing and offer a new perspective on what might constitute successful stuttering treatment. Further, clinical research support is provided for Acceptance and Commitment Therapy delivered in a group format as a promising and novel intervention for adults who stutter. EDUCATIONAL OBJECTIVES: The reader will be able to: (a) appreciate the potential for Acceptance and Commitment Therapy for adults who stutter; (b) identify the improvements participants experienced in psychosocial functioning and frequency of stuttered speech; (c) appreciate the six core processes of Acceptance and Commitment Therapy; and (d) appreciate the differences between an ACT model of intervention for adults who stutter compared to a CBT approach.


Subject(s)
Psychotherapy , Social Adjustment , Stuttering/therapy , Adult , Aged , Female , Humans , Male , Middle Aged , Mind-Body Therapies , Psychotherapy/methods , Speech , Stuttering/psychology , Surveys and Questionnaires , Treatment Outcome , Young Adult
3.
J Fluency Disord ; 37(2): 135-48, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22531288

ABSTRACT

UNLABELLED: Stuttering impacts on the child in a variety of ways, notably in terms of communicative impairment and psychosocial impact. In addition, the stuttering disorder has a holistic impact, affecting those with whom the child who stutters lives. Within the family constellation, the closest person to the individual who stutters is often their sibling. This study investigated the experiences of fluent siblings of children who stutter to examine the impact that stuttering may have on their lives. A mixed methods research design incorporated qualitative semi-structured interviews and quantitative questionnaires. The results of the qualitative investigation revealed four aspects of children's lives that were affected by having a sibling who stuttered: the relationship between siblings, the impact on the fluent sibling, the impact on the parent relationship with both children, and the impact on the sibling's relationship with others. Findings revealed that siblings of children who stutter exhibited strongly negative emotions, and differing levels of responsibility associated with their involvement in the actual stuttering management programme. Furthermore, for the fluent sibling, secondary to having a brother or sister who stuttered, communication with and attention from their parents was variable. The results of the quantitative component of the study revealed children who stutter and their siblings demonstrated significantly greater closeness, and concurrently, increased conflict and status disparity than did the control fluent sibling dyads. The parents of the experimental sibling dyads also demonstrated significantly greater partiality towards a child, namely the child who stuttered, than did the parents of the control sibling dyads. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) identify the themes associated with having a sibling who stutters; (2) identify how the quality of the sibling relationship differs between sibling dyads that do and do not consist of a sibling who stutters; and (3) discuss the clinical implications of the results with regards to working with children who stutter and their families.


Subject(s)
Siblings/psychology , Stuttering/psychology , Case-Control Studies , Child , Child, Preschool , Female , Humans , Interpersonal Relations , Interviews as Topic , Male , Parent-Child Relations , Surveys and Questionnaires
4.
J Commun Disord ; 45(2): 98-110, 2012.
Article in English | MEDLINE | ID: mdl-22205038

ABSTRACT

UNLABELLED: Parental input has been described as influential in early childhood stuttering yet the exact nature of this influence remains equivocal. The present study aimed to examine whether quantitative measures of parenting styles, parent and peer attachment patterns, and parent- and self-reported child behaviour could differentiate between school-aged children who stutter (CWS) (n=10) and their fluent peers (n=10). In addition, qualitative individual semi-structured interviews with all CWS were conducted to gain insight into their life experiences and reflections in relation to stuttering. The interviews were classified into ancillary themes of school, peers and parents. Quantitative findings revealed that CWS perceived their parents with significantly lower attachment, particularly in relation to trust, and parents of CWS perceived their children with significantly higher maladjustments than fluent counterparts. Qualitative themes emerged pertaining to attitudes, perceptions and relationships with teachers, peers and parents, with consistent experiences of teasing and bullying reported as a consequence of the stutter. The majority of participants recounted frustration with the nature in which their parents attempted to remediate their stuttering. Collectively, these findings highlight imperative management considerations for school-aged CWS and their parents. The usefulness of quantitative and qualitative research paradigms is also emphasised. LEARNING OUTCOMES: The reader will be able to: (1) identify themes associated with the impact a childhood stutter has on parent and peer relationships; (2) identify how the quality of the parent child relationship is influenced by parenting styles and attachment; and (3) discuss the clinical implications of the results for children who stutter and their families.


Subject(s)
Object Attachment , Parenting/psychology , Stuttering/psychology , Adolescent , Attitude to Health , Bullying/psychology , Case-Control Studies , Child , Child Behavior/psychology , Female , Humans , Male , Parent-Child Relations , Peer Group , Psychological Tests , Severity of Illness Index , Stuttering/etiology , Trust/psychology
5.
J Clin Neurosci ; 13(6): 639-42, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16814549

ABSTRACT

Transcranial magnetic stimulation mapping of the motor cortical projection to the hand was performed in a group of patients with Parkinson's disease (PD) of variable duration to determine whether there is evidence of cortical reorganisation. Map shifts were found in the majority of PD cases (12/15), in untreated early cases as well as treated cases of longer duration, and there was a correlation between inter-side difference in the severity of PD symptoms (Unified Parkinson's Disease Rating Scale) and interhemispheric map displacement (r=0.60; P=0.018). These findings indicate that there is reorganisation of the corticomotor representation of the hand in PD, even at a relatively early stage of the disease, and suggest a dynamic process of reorganisation in the motor cortex due to an increase in the pallidal inhibitory inputs to the thalamo-cortical projections.


Subject(s)
Motor Cortex/pathology , Motor Cortex/physiopathology , Parkinson Disease/physiopathology , Aged , Brain Mapping , Evoked Potentials, Motor/physiology , Evoked Potentials, Motor/radiation effects , Female , Follow-Up Studies , Humans , Male , Middle Aged , Parkinson Disease/pathology , Transcranial Magnetic Stimulation/methods
6.
J Neurol ; 253(8): 1048-53, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16607472

ABSTRACT

OBJECTIVE: To determine if task performance and fatiguability during repeated low-level contractions of an intrinsic hand muscle differ in a group of MS subjects compared with a control group, and what central changes accompany the development of fatigue and the period of recovery, whether these measures are related to subjective ratings of fatigue or perception of effort. METHODS: Force of index finger abduction, rating of perceived effort, and motor evoked potential amplitude and silent period duration were measured during and after a 20-min. intermittent submaximal (40%) contraction of the first dorsal interosseous muscle in 23 clinically definite MS subjects with mild-moderate symptoms, and 15 controls. RESULTS: Rating of perceived effort increased at a greater rate in the MS group than in control subjects during exercise, and this was associated with larger increases in both MEP amplitude and silent period duration. CONCLUSIONS: Submaximal fatiguing exercise is associated with an enhanced central motor drive and increased perception of effort in MS. SIGNIFICANCE: MS subjects can increase central drive during fatiguing exercise to a greater degree than controls, but this is associated with greater perceived exertion. These factors may underlie the more general complaint of fatigue experienced by people with MS.


Subject(s)
Fatigue/etiology , Fatigue/physiopathology , Multiple Sclerosis/complications , Multiple Sclerosis/physiopathology , Physical Exertion , Psychomotor Performance , Adult , Case-Control Studies , Electromyography , Evoked Potentials, Motor , Evoked Potentials, Somatosensory , Female , Hand , Humans , Male , Middle Aged , Muscle Contraction , Surveys and Questionnaires , Time Factors , Transcranial Magnetic Stimulation
7.
Mov Disord ; 21(7): 900-5, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16532455

ABSTRACT

Primary orthostatic tremor (OT) is a rare but disabling condition characterized by leg tremor and feelings of instability during stance. Previous studies have reported a reduction in OT symptoms with gabapentin treatment. In this study, we report on the benefits of gabapentin treatment in a double-blind placebo-controlled crossover study of 6 OT patients. First, the maximally effective gabapentin dosage (600-2,700 mg/day) for each patient was determined during an initial dose-titration phase. Patients were then studied 7 days after drug withdrawal and again after two 2-week periods of treatment with either gabapentin or placebo, using force platform posturography to quantify postural sway and tremor. Other medications for OT were continued unchanged. Symptomatic response was assessed by a patient-rated severity scale and quality of life (QOL) questionnaire. All patients reported an increase in symptoms during the washout phase and symptom reduction (50%-75%) during gabapentin treatment. Tremor amplitude was reduced to 79% +/- 11% and sway area to 71% +/- 11% of the placebo state. QOL improved in all patients, no adverse drug effects were noted, and symptomatic benefit was maintained at follow-up (mean = 19 months). The findings confirm that gabapentin is an effective treatment for OT, reducing both tremor and postural instability and improving quality of life, and support its use as add-on or first-line therapy for OT.


Subject(s)
Amines/therapeutic use , Antiparkinson Agents/therapeutic use , Cyclohexanecarboxylic Acids/therapeutic use , Dizziness/drug therapy , Postural Balance/drug effects , Tremor/drug therapy , gamma-Aminobutyric Acid/therapeutic use , Aged , Amines/adverse effects , Antiparkinson Agents/adverse effects , Cross-Over Studies , Cyclohexanecarboxylic Acids/adverse effects , Dizziness/diagnosis , Double-Blind Method , Female , Follow-Up Studies , Gabapentin , Humans , Male , Middle Aged , Neurologic Examination , Quality of Life , Recurrence , Substance Withdrawal Syndrome/diagnosis , Tremor/diagnosis , gamma-Aminobutyric Acid/adverse effects
8.
J Clin Neurosci ; 13(1): 91-5, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16410203

ABSTRACT

To determine whether frontal lobe regions, including Broca's area, dorsolateral prefrontal cortex (DLPFC) and supplementary motor area (SMA), are differentially activated during lexical and semantic language tasks, we used functional magnetic resonance imaging in eight healthy right-handed subjects silently performing two semantic tasks (adjective and verb generation) and a lexical retrieval task (noun recall). Activation was observed in Broca's area, DLPFC and SMA for all tasks. Broca's area activation was approximately doubled during the semantic tasks compared with the lexical task (verbs vs nouns: 19.1+/-4.5 vs 8.9+/-1.6 voxels, p=0.02; adjectives vs nouns 24.4+/-7.5 vs 10.1+/-2.8 voxels, p=0.04); however, there were no significant differences in the DLFPC or SMA across tasks. We conclude that Broca's area is more active during tasks that have a semantic content, whereas areas involved in preparatory processing (SMA) and memory retrieval (DLPFC) are engaged equally during both types of task.


Subject(s)
Frontal Lobe/blood supply , Frontal Lobe/physiology , Magnetic Resonance Imaging , Semantics , Vocabulary , Adult , Brain Mapping , Female , Functional Laterality , Humans , Image Processing, Computer-Assisted/methods , Male , Mental Recall/physiology , Middle Aged , Oxygen/blood
9.
Clin Neurophysiol ; 117(1): 61-6, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16326137

ABSTRACT

OBJECTIVE: We hypothesised that facilitatory I-wave interaction set up by paired-pulse transcranial magnetic stimulation delivered with I-wave periodicity (iTMS) may reinforce trans-synaptic events and provide a means for modulating synaptic plasticity and cortical excitability. Our objective was to determine whether prolonged iTMS can increase corticospinal excitability, and whether this form of stimulation can have lasting aftereffects. METHODS: Paired stimuli of equal strength with a 1.5 ms inter-stimulus interval were delivered for 30 min at a rate of 0.2 Hz. Motor threshold and motor evoked potential (MEP) amplitude to single-pulse TMS was compared before and after intervention. RESULTS: Paired-pulse MEP amplitude increased linearly throughout the period of iTMS, and had increased five-fold by the end of the stimulation period. Single-pulse MEP amplitude was increased a mean of four-fold for 10 min after stimulation. Motor threshold was unaffected. CONCLUSIONS: iTMS is an effective method for increasing excitability of the human motor cortex, and probably acts by increasing synaptic efficacy. SIGNIFICANCE: Reinforcement of trans-synaptic events by iTMS may provide a means to investigate and modulate synaptic plasticity in the brain.


Subject(s)
Motor Cortex/radiation effects , Neural Inhibition/radiation effects , Neuronal Plasticity/radiation effects , Periodicity , Pyramidal Tracts/radiation effects , Transcranial Magnetic Stimulation , Adult , Differential Threshold/radiation effects , Dose-Response Relationship, Radiation , Electromyography/methods , Evoked Potentials, Motor/physiology , Evoked Potentials, Motor/radiation effects , Female , Humans , Male , Motor Cortex/physiology , Muscle, Skeletal/physiology , Neural Inhibition/physiology , Pyramidal Tracts/physiology , Reaction Time/physiology , Reaction Time/radiation effects , Time Factors
10.
Exp Brain Res ; 170(2): 191-8, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16328285

ABSTRACT

The central processes occurring during fatiguing exercise are not well understood, however transcranial magnetic stimulation (TMS) studies have reported increases both in corticomotor excitability, as measured by the motor-evoked potential (MEP) amplitude, and in long-interval intracortical inhibition, as measured by the duration of the post-MEP silent period. To determine whether short-interval cortical inhibition (SICI) is modulated by fatiguing exercise, we used single and paired-pulse TMS to measure MEP amplitude and SICI for the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles of the hand during, and for 20 min after, a 10-min intermittent maximal voluntary abduction of the index finger designed to fatigue the FDI muscle. For the FDI, the index of SICI increased at the onset of exercise (from 0.25+/-0.05 to 0.55+/-0.11, P < 0.05) and then decreased progressively as force declined. At the beginning of recovery, SICI again increased (0.57+/-0.11, P < 0.05) and remained elevated for the 20-min recovery period. In contrast, SICI for ADM did not change during or after exercise. MEP amplitude for both the FDI and ADM increased above baseline during exercise and then decreased below baseline during the recovery period. These results demonstrate that there are significant changes in SICI during and after a fatiguing exercise protocol that are isolated to the representation of the fatigued muscle. The inter-relationship between the changes in excitation and inhibition suggests the presence of a measured and adaptive process of modulation in central excitation and inhibition acting to increase corticomotor drive to the exercising muscle as fatigue is developing.


Subject(s)
Evoked Potentials, Motor/physiology , Hand/physiology , Motor Cortex/physiology , Muscle Contraction/physiology , Muscle Fatigue/physiology , Neural Inhibition/physiology , Adaptation, Physiological/physiology , Adult , Efferent Pathways/physiology , Electromyography , Exercise/physiology , Female , Hand/innervation , Humans , Male , Muscle, Skeletal/innervation , Muscle, Skeletal/physiology , Physical Fitness/physiology , Transcranial Magnetic Stimulation
11.
Exp Brain Res ; 167(2): 160-4, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16034578

ABSTRACT

We have compared functional MRI signals in primary sensorimotor cortex (SM1) during a paced motor task of each hand before and after unimanual (right hand) fatiguing exercise. Our aims were to determine whether the degree of activation is different when a motor task is performed after a fatiguing exercise, and whether there are any differences in activation between movement of the fatigued and non-fatigued hands. There was a significant reduction in the number of voxels activated in SM1 in the hemisphere contralateral to movement of both the fatigued hand (38 +/- 5 pre-exercise versus 21 +/- 3 post-exercise; P<0.05) and the non-fatigued hand (32 +/- 4 pre-exercise vs 18 +/- 4 post-exercise; P<0.05). There was no significant difference in the magnitude of the functional magnetic resonance imaging signal before or after exercise, however, the variance increased significantly after exercise (6.0 +/- 0.5 pre-exercise vs 7.3 +/- 0.6 post-exercise; P<0.01). Reduced functional activation in SM1 may reflect increased variability in the activation rather than a reduction in activation of cortical motor networks after fatigue.


Subject(s)
Exercise/physiology , Fatigue/physiopathology , Hand/physiopathology , Somatosensory Cortex/physiology , Task Performance and Analysis , Adult , Brain Mapping , Female , Functional Laterality/physiology , Humans , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Male , Middle Aged , Oxygen/blood , Psychomotor Performance/physiology , Somatosensory Cortex/blood supply
12.
J Neurol ; 252(7): 765-71, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15750708

ABSTRACT

Our objective was to determine whether there are changes in the corticomotor map for the hand in multiple sclerosis, and whether these changes correlate with indices of motor function and measures of corticomotor conduction or excitability. Transcranial magnetic stimulation (TMS) maps, motor evoked potential (MEP) latency and amplitude, motor threshold and EDSS and Purdue-pegboard measurements were made in 26 subjects with relapsing-remitting multiple sclerosis. Correlations were sought between these measurements using the Pearson product-moment correlation with a level of significance of p = 0.05 (two-tailed). Map displacement was positively correlated with MEP latency (p = 3 x 10(-4)) and EDSS (p = 0.007), and negatively correlated with Purdue score (p = 4 x 10(-4)). Purdue scores correlated with all MEP parameters (latency, p = 4 x 10(-10); threshold, p = 4 x 10(-6); amplitude, p = 0.003). We conclude that motor reorganisation is associated with impaired corticomotor conduction and may reflect a process of neural plasticity associated with axonal demyelination in MS. An understanding of motor function in MS should incorporate models of both axonal demyelination and conduction deficits as well as neural plasticity.


Subject(s)
Evoked Potentials, Motor/physiology , Motor Cortex/physiopathology , Multiple Sclerosis/physiopathology , Adult , Aged , Brain Mapping , Differential Threshold/radiation effects , Disability Evaluation , Electric Stimulation/methods , Evoked Potentials, Motor/radiation effects , Female , Humans , Magnetics , Male , Middle Aged , Motor Cortex/pathology , Motor Cortex/radiation effects , Multiple Sclerosis/pathology , Multiple Sclerosis/therapy , Neurologic Examination/methods , Reaction Time/physiology , Reaction Time/radiation effects , Statistics as Topic/methods
13.
Mov Disord ; 20(7): 865-70, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15719416

ABSTRACT

Primary orthostatic tremor (OT) is characterized by leg tremor and instability on standing. High frequency (13-18 Hz) tremor bursting is present in leg muscles during stance, and posturography has shown greater than normal sway. We report on an open-label add-on study of gabapentin in 6 patients with OT. Six patients were studied with surface electromyography, force platform posturography, and a modified Parkinson's disease questionnaire (PDQ-39) quality of life (QOL) scale before and during treatment with gabapentin 300 mg t.d.s. If on other medications for OT, these were continued unchanged. Of the 6 patients, 4 reported a subjective benefit of 50 to 75% with gabapentin, 3 of whom showed reduced tremor amplitude and postural sway of up to 70%. Dynamic balance improved in all 3 patients who completed the protocol. QOL data from 5 patients showed improvement in all cases. No adverse effects were noted. Gabapentin may improve tremor, stability, and QOL in patients with OT, and symptomatic response correlated with a reduction in tremor amplitude and postural sway. The findings confirm previous reports of symptomatic benefit with gabapentin and provide justification for larger controlled clinical trials. Further work is required to establish the optimal dosage and to validate the methods used to quantify the response to treatment.


Subject(s)
Amines/therapeutic use , Anticonvulsants/therapeutic use , Cyclohexanecarboxylic Acids/therapeutic use , Posture/physiology , Quality of Life , Tremor/drug therapy , gamma-Aminobutyric Acid/therapeutic use , Aged , Electromyography/methods , Female , Gabapentin , Humans , Male , Middle Aged , Muscle Contraction/drug effects , Muscle, Skeletal/drug effects , Pressure , Surveys and Questionnaires , Tremor/physiopathology , Tremor/psychology
14.
J Clin Neurosci ; 12(1): 102-4, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15639429

ABSTRACT

BACKGROUND: Primary writing tremor (PWT) is a task-specific tremor of uncertain origin. There has been debate as to whether PWT represents a variant of essential tremor or a tremulous form of focal dystonia related to writer's cramp. In writer's cramp there is evidence of changes in intracortical inhibition (ICI), as well as cortical motor reorganisation. OBJECTIVE: To study corticomotor organisation and short-latency ICI in a patient with typical task-specific PWT. METHODS: Transcranial magnetic stimulation mapping of the corticomotor representation of the hand and studies of ICI using paired-pulse stimulation were performed in a 47-year-old right-handed woman with a pure task-specific writing tremor. RESULTS: The motor maps for the hand were displaced posteriorly on both sides and reverted to a normal position after treatment with botulinum toxin. Short-latency ICI was reduced for the dominant hand. CONCLUSION: The findings indicate reorganisation and disinhibition of the corticomotor projection to the hand and point to the participation of cortical centres in the origin of PWT.


Subject(s)
Botulinum Toxins, Type A/therapeutic use , Handwriting , Motor Cortex/physiopathology , Neuromuscular Agents/therapeutic use , Tremor/physiopathology , Tremor/therapy , Brain Mapping , Electroencephalography , Evoked Potentials, Motor/physiology , Female , Humans , Middle Aged , Transcranial Magnetic Stimulation , Tremor/psychology
15.
J Clin Neurosci ; 11(8): 845-8, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15519860

ABSTRACT

BACKGROUND AND PURPOSE: Mapping of eloquent cortex using blood-oxygen-level-dependent (BOLD) contrast functional MRI (fMRI) has rapidly gained acceptance as part of the evaluation of patients being considered for neurosurgical interventions. The BOLD signal measures local susceptibility in the blood, which can change during periods of increased neuronal activation as a result of alteration in blood flow and cerebral oxygen utilisation. Vascular anomalies could influence the BOLD signal via their effects on both blood flow and susceptibility. METHODS: In the present study we have compared the fMRI signal associated with functional activation near arteriovenous malformations and cavernomas in a group of patients referred for pre-surgical mapping of eloquent cortex. RESULTS: The magnitude of the BOLD signal was not different for the cavernoma group and the AVM group (mean percentage signal change 6.3% vs. 5.5%). For subjects with cavernoma, there was an increase in cavernoma volume on the functional images compared to T1-weighted anatomical images (mean 570%), and a BOLD signal was only detected outside the enlarged cavernoma. CONCLUSION: The findings show that susceptibility effects associated with cavernoma, most likely due to hemosiderin deposition, can result in an apparent increase in the separation between the BOLD signal and the cavernoma itself. This could lead to falsely high levels of surgical confidence during neurosurgical resection. Differential patterns of blood flow associated with cavernoma and AVM do not appear to significantly affect the BOLD signal magnitude.


Subject(s)
Arteriovenous Malformations/pathology , Brain Mapping , Brain Neoplasms/pathology , Cerebral Cortex/blood supply , Magnetic Resonance Imaging , Adolescent , Adult , Cerebral Cortex/pathology , Female , Hemangioma, Cavernous , Humans , Image Processing, Computer-Assisted/methods , Male , Middle Aged , Oxygen/blood
16.
Hum Mov Sci ; 23(3-4): 379-87, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15541524

ABSTRACT

We have previously shown that during rhythmic passive movement of the index finger, the amplitude of the motor evoke potential (MEP) of the first dorsal interosseous muscle (FDI) as the index finger moved through mid-range adduction, is significantly reduced compared to rest [Edwards, D. J., Thickbroom, G. W., Byrnes, M. L., Ghosh, S., & Mastaglia, F. L. (2002). Reduced corticomotor excitability with passive movement: A study using Transcranial Magnetic Stimulation. Human Movement Science 21, 533-540]. In the present study we have investigated the time-course of this phenomenon. We found that MEP amplitude was significantly reduced at the mid-range position in the first cycle of movement (50+/-6% of resting baseline values), and did not vary across subsequent cycles (10 cycles in 50 s), but that MEP amplitude returned to baseline values within 1s of cessation of movement. The results suggest that the pattern of afferent discharge set up by the kinematics of the movement acting at spinal or supraspinal levels underlies the inhibition observed, rather than an effect of central origin or a cumulative effect of ongoing cyclic movement.


Subject(s)
Brain/physiology , Movement/physiology , Neural Inhibition/physiology , Adult , Evoked Potentials, Motor/physiology , Female , Fingers/physiology , Humans , Magnetics , Male , Middle Aged , Periodicity , Time Factors
17.
Clin Neurophysiol ; 115(9): 2144-50, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15294217

ABSTRACT

OBJECTIVE: The contribution of cortical reorganization to motor recovery after a subcortical stroke is uncertain. The purpose of the study was to investigate the relationship between changes in motor cortex organization, and the degree of motor function after a subcortical stroke. METHODS: Transcranial magnetic stimulation mapping of the corticomotor projection to the hand was performed in 27 patients who had suffered a subcortical ischemic stroke resulting in an upper limb motor deficit up to 23 years previously. Corticospinal conduction was assessed by measurements of motor evoked potential latency, amplitude and threshold. Motor function in the upper limb was assessed using the Motor Assessment Scale for Stroke and measurements of grip strength. RESULTS: Motor maps for the hand were displaced on the affected side relative to the unaffected side in 17 patients. In 10 of these patients in whom corticospinal conduction had normalized, there was a strong positive correlation between the magnitude of the map shift and grip strength in the affected hand (r=0.79; P=0.006). In the other seven patients with a map shift, in whom corticospinal conduction was still impaired, there was a tendency for a larger map area to be associated with better motor function, and in the group as a whole there was a correlation between map area and grip strength (r=0.52; P=0.005). CONCLUSIONS: The present findings provide evidence that the cortical plasticity and reorganization that occurs after a subcortical stroke is functionally significant and contributes to motor outcome.


Subject(s)
Motor Cortex/pathology , Motor Cortex/physiology , Neuronal Plasticity/physiology , Recovery of Function/physiology , Stroke/physiopathology , Adult , Aged , Electric Stimulation , Female , Hand/innervation , Humans , Magnetics , Male , Middle Aged , Motor Activity/physiology , Stroke Rehabilitation
18.
Neurotoxicol Teratol ; 25(3): 303-10, 2003.
Article in English | MEDLINE | ID: mdl-12757827

ABSTRACT

This study tested the hypothesis that prenatal ethanol exposure (PEE) during the brain growth spurt (BGS) in the guinea pig suppresses the glutamate-NMDA receptor-nitric oxide synthase (NOS) signaling system in the developing hippocampus. Pregnant guinea pigs [term, about gestational day (GD) 68] received daily oral administration of 2 g ethanol/kg maternal body weight/day on GD 43 and/or GD 44 and then 4 g ethanol/kg maternal body weight/day from GD 45 to GD 62, isocaloric-sucrose/pair-feeding or water. Offspring were studied at GD 63 (near-term fetus) and postnatal day (PD) 10 (young postnatal life). Maternal blood ethanol concentration during ethanol treatment, pregnancy outcome variables, no change in spontaneous locomotor activity, and decreased brain and cerebral cortical weight data were reported previously [Neurotoxicol. Teratol. 23 (2001) 355]. This BGS-PEE regimen did not affect hippocampal stimulated glutamate release in young postnatal offspring, NMDA receptors as assessed by [3H]MK-801 binding, or NOS activity in near-term fetal offspring. Furthermore, BGS-PEE did not affect the number of hippocampal CA1 and CA3 pyramidal cells and dentate gyrus granule cells in defined locations of these three regions in the hippocampal formation. These findings are in contrast to the effects of chronic prenatal exposure to this ethanol regimen throughout gestation, including suppression of the hippocampal glutamate-NMDA receptor-NOS signaling system, decreased number of hippocampal CA1 pyramidal cells, increased spontaneous locomotor activity, and impaired performance in the Morris water maze.


Subject(s)
Brain/embryology , Central Nervous System Depressants/toxicity , Ethanol/toxicity , Hippocampus/embryology , Prenatal Exposure Delayed Effects , Signal Transduction/drug effects , Animals , Body Weight/drug effects , Brain/drug effects , Brain/growth & development , Female , Glutamic Acid/metabolism , Guinea Pigs , Hippocampus/enzymology , Hippocampus/growth & development , Hippocampus/metabolism , Nitric Oxide Synthase/metabolism , Organ Size/drug effects , Pregnancy , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
19.
Neuroimage ; 18(3): 670-4, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12667844

ABSTRACT

Early electrophysiological studies during sensory stimulation in the anesthetized cat and more recent functional imaging studies during voluntary movement in humans have provided evidence for two separate representations of the body in the anterior and posterior lobes of the cerebellum; however, the functional role of these body maps in motor and sensory processing is not known. The aims of the present study were to determine whether this dual representation is also present during passive movement, and to compare the pattern of activation with that obtained during voluntary movement. Functional MRI measurements were undertaken in 14 subjects who performed right index finger flexion and extension movements at approximately 1 Hz, or had their finger moved passively at the same rate and through the same angle using a pneumatic device. During passive movement, dual activation was detected in the ipsilateral cerebellum, in the anterior lobe, and in the posterior lobe. A similar pattern of activation was observed during voluntary movement; however, the overall magnitude was about doubled. These data provide evidence for a dual ipsilateral representation of the hand in the rostral and caudal cerebellar cortex during passive as well as voluntary movements, with the rostral representation being the dominant one, and indicate that both of these areas are involved in kinesthetic sensory and motor processing.


Subject(s)
Cerebellar Cortex/physiology , Fingers/innervation , Hand/innervation , Magnetic Resonance Imaging , Motor Activity/physiology , Range of Motion, Articular/physiology , Adult , Brain Mapping , Echo-Planar Imaging , Female , Humans , Image Processing, Computer-Assisted , Isometric Contraction/physiology , Kinesthesis , Male
20.
Mov Disord ; 18(4): 395-402, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12671945

ABSTRACT

Previous work has suggested that there may be a widespread disturbance of motor control mechanisms in patients with cervical dystonia. In the present study, we used transcranial magnetic stimulation to investigate the topography of the corticomotor projection to the abductor pollicis brevis (APB) muscle in 10 subjects with idiopathic torticollis. Threshold-adjusted stimuli were delivered at multiple scalp sites during a low-level voluntary contraction of the APB, and maps were generated of motor evoked potential amplitude versus scalp site. The cortical maps for the APB on the side opposite to the direction of head rotation were displaced laterally or posteriorly in all subjects and reverted to a more normal position after botulinum toxin injection of the cervical muscles in 5 subjects. The findings point to a reversible reorganisation of the corticomotor representation of the hand on the same side as the sternocleidomastoid (SCM) muscle that is involved in producing the dystonia. These results provide further evidence for the involvement of cortical centres and for a more widespread abnormality of motor control mechanisms in focal dystonia. The findings also support the notion that head turning is chiefly mediated by the hemisphere ipsilateral to the direction of the head rotation by means of a corticomotor projection to the contralateral SCM.


Subject(s)
Cerebral Cortex/physiopathology , Hand/innervation , Motor Cortex/physiopathology , Neuronal Plasticity/physiology , Torticollis/physiopathology , Adult , Aged , Botulinum Toxins/administration & dosage , Cerebral Cortex/drug effects , Contingent Negative Variation/physiology , Dominance, Cerebral/physiology , Female , Humans , Injections, Intramuscular , Male , Middle Aged , Motor Cortex/drug effects , Motor Neurons/drug effects , Motor Neurons/physiology , Muscle, Skeletal/innervation , Neck Muscles/innervation , Neuronal Plasticity/drug effects , Torticollis/drug therapy
SELECTION OF CITATIONS
SEARCH DETAIL
...