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Hinkley LB, Webster R, Byl NN, Nagarajan SS. Neuroimaging characteristics of patients with focal hand dystonia. J Hand Ther 2009; 22:125-34; quiz 135. [PMID: 19217255 PMCID: PMC6287964 DOI: 10.1016/j.jht.2008.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 11/26/2008] [Accepted: 11/26/2008] [Indexed: 02/03/2023]
Abstract
NARRATIVE REVIEW: Advances in structural and functional imaging have provided both scientists and clinicians with information about the neural mechanisms underlying focal hand dystonia (FHd), a motor disorder associated with aberrant posturing and patterns of muscle contraction specific to movements of the hand. Consistent with the hypothesis that FHd is the result of reorganization in cortical fields, studies in neuroimaging have confirmed alterations in the topography and response properties of somatosensory and motor areas of the brain. Noninvasive stimulation of these regions also demonstrates that FHd may be due to reductions in inhibition between competing sensory and motor representations. Compromises in neuroanatomical structure, such as white matter density and gray matter volume, have also been identified through neuroimaging methods. These advances in neuroimaging have provided clinicians with an expanded understanding of the changes in the brain that contribute to FHd. These findings should provide a foundation for the development of retraining paradigms focused on reversing overlapping sensory representations and interactions between brain regions in patients with FHd. Continued collaborations between health professionals who treat FHd and research scientists who examine the brain using neuroimaging tools are imperative for answering difficult questions about patients with specific movement disorders.
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Affiliation(s)
| | - Rebecca Webster
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nancy N. Byl
- Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, San Francisco, CA 94143, USA
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Abstract
Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements. Historically these peculiar postures were considered psychogenic but have now been classified as forms of dystonia. Writer's cramp is the most commonly identified task-specific dystonia and has features typical of this group of disorders. Symptoms may begin with lack of dexterity during performance of a specific motor task with increasingly abnormal posturing of the involved body part as motor activity continues. Initially, the dystonia may manifest only during the performance of the inciting task, but as the condition progresses it may also occur during other activities or even at rest. Neurological exam is usually unremarkable except for the dystonia-related abnormalities. Although the precise pathophysiology remains unclear, increasing evidence suggests reduced inhibition at different levels of the sensorimotor system. Symptomatic treatment options include oral medications, botulinum toxin injections, neurosurgical procedures, and adaptive strategies. Prognosis may vary depending upon body part involved and specific type of task affected. Further research may reveal new insights into the etiology, pathophysiology, natural history, and improved treatment of these conditions.
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Affiliation(s)
- Diego Torres-Russotto
- Department of Neurology, Washington University in St. Louis. St. Louis, Missouri, USA
| | - Joel S. Perlmutter
- Department of Neurology, Washington University in St. Louis. St. Louis, Missouri, USA
- Departments of Radiology and Anatomy and Neurobiology and Programs in Physical Therapy and Occupational Therapy, Washington University in St. Louis. St. Louis, Missouri, USA
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Obermann M, Yaldizli O, de Greiff A, Konczak J, Lachenmayer ML, Tumczak F, Buhl AR, Putzki N, Vollmer-Haase J, Gizewski ER, Diener HC, Maschke M. Increased basal-ganglia activation performing a non-dystonia-related task in focal dystonia. Eur J Neurol 2008; 15:831-8. [DOI: 10.1111/j.1468-1331.2008.02196.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Breakefield XO, Blood AJ, Li Y, Hallett M, Hanson PI, Standaert DG. The pathophysiological basis of dystonias. Nat Rev Neurosci 2008; 9:222-34. [PMID: 18285800 DOI: 10.1038/nrn2337] [Citation(s) in RCA: 318] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dystonias comprise a group of movement disorders that are characterized by involuntary movements and postures. Insight into the nature of neuronal dysfunction has been provided by the identification of genes responsible for primary dystonias, the characterization of animal models and functional evaluations and in vivo brain imaging of patients with dystonia. The data suggest that alterations in neuronal development and communication within the brain create a susceptible substratum for dystonia. Although there is no overt neurodegeneration in most forms of dystonia, there are functional and microstructural brain alterations. Dystonia offers a window into the mechanisms whereby subtle changes in neuronal function, particularly in sensorimotor circuits that are associated with motor learning and memory, can corrupt normal coordination and lead to a disabling motor disorder.
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Affiliation(s)
- Xandra O Breakefield
- Department of Neurology and Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
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Toxopeus CM, de Vries PM, de Jong BM, Johnson KA, George MS, Bohning DE, Walker J, Leenders KL. Cerebral activation patterns related to initiation and inhibition of hand movement. Neuroreport 2007; 18:1557-60. [PMID: 17885601 DOI: 10.1097/wnr.0b013e3282efa0a2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Sequential ordering of purposeful movements includes distinct transitions between muscle contraction and relaxation. To explore cerebral activation patterns underlying such movement initiation and inhibition, we applied functional magnetic resonance imaging to test the effects of (1) ballistic movement (dominated by initiation), (2) movement with stepwise interruption (dominated by inhibition) and (3) smooth movements. Right-hand movements were performed by 21 healthy participants. In the basal ganglia, ballistic movements evoked putamen activation, indicating its specific contribution to initiation. Stepwise interrupted movement induced increased activation of the caudate nucleus, globus pallidus and subthalamic nucleus whereas, at the cortical level, supplementary motor area activation increased. This indicates a specific basal ganglia-thalamocortical circuit involved in motor inhibition.
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Affiliation(s)
- Carolien M Toxopeus
- Department of Neurology, University Medical Centre Groningen, University of Groningen, The Netherlands
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56
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de Jong BM, Paans AMJ. Medial versus lateral prefrontal dissociation in movement selection and inhibitory control. Brain Res 2007; 1132:139-47. [PMID: 17173869 DOI: 10.1016/j.brainres.2006.11.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 11/02/2006] [Accepted: 11/06/2006] [Indexed: 11/21/2022]
Abstract
We aimed to test the hypothesis that the cerebral selection of movement includes active suppression of unwanted movements. To that end, a cerebral activation paradigm was used in which index finger flexion was compared with similar movement, made together with fingers 3, 4, 5. Cerebral activations were assessed by positron emission tomography (PET) measurements of cerebral perfusion in 10 healthy subjects, during the two motor tasks and rest. Statistical parametric mapping (SPM) revealed significant increase of (antero)medial prefrontal activity and subtle changes in pallidum and thalamus in the condition of less movement, i.e. isolated index finger flexion contrasted to full-hand flexion. These increases indicated a mechanism of selection mediated by active suppression of unwanted movements. Suppression of all motor responses was inferred from anterolateral prefrontal activation related to rest (with only auditory cues), contrasted to both motor conditions. This segregation of inhibitory functions specifies the complementary character of response selection and inhibitory control, in such a way, that towards the medial prefrontal surface, a transition from general to increasingly selective inhibition allows the internal ordering of action.
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Affiliation(s)
- B M de Jong
- Department of Neurology, University Medical Center Groningen, Hanzeplein 1, POB 30.001, Groningen, The Netherlands.
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57
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Berger HJ, van der Werf SP, Horstink CA, Cools AR, Oyen WJ, Horstink MW. Writer's cramp: restoration of striatal D2-binding after successful biofeedback-based sensorimotor training. Parkinsonism Relat Disord 2006; 13:170-3. [PMID: 17107822 DOI: 10.1016/j.parkreldis.2006.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 08/28/2006] [Accepted: 09/12/2006] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Previous studies of writer's cramp have detected cerebral sensorimotor abnormalities in this disorder and, more specifically, a reduced striatal D2-binding as assessed by [(123)I]IBZM SPECT. However, empirical data were lacking about the influence of effective biofeedback-based sensorimotor training on D2 receptor binding. METHODS To determine whether there is a restoration of D2-binding after successful sensorimotor treatment, pre- and posttreatment SPECTs were compared in five patients with writer's cramp and correlated with improvement in handwriting. RESULTS After treatment, the clinical and electromyographic picture appeared substantially improved connected with a significant increase in D2-binding to nearly normal levels similar to normative data in age/sex-matched healthy subjects. CONCLUSION The current study supported the view that writer's cramp results from a plastic adaptation of a rectifiable nigrostriatal dopaminergic system and that effective sensorimotor training leads to increased efficacy of striatal dopaminergic transmission.
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Affiliation(s)
- Hans J Berger
- Department of Medical Psychology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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Abstract
In conclusion, musicians' focal dystonia is a significant and potentially career-ending neurological condition of which physiatrists and other performing arts medicine clinicians should be aware. Pathology has been identified in the somatosensory cortex, and in the motor cortex and basal ganglia. Although advances have been made in the elucidating some of the pathologic changes in focal dystonia, better understanding is needed. Current treatments such as retraining, splinting, oral medications, and botulinum toxin injections are limited. Therefore, the ultimate goal for focal dystonia is to prevent this disabling disorder of instrumental musicians.
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Blood AJ, Tuch DS, Makris N, Makhlouf ML, Sudarsky LR, Sharma N. White matter abnormalities in dystonia normalize after botulinum toxin treatment. Neuroreport 2006; 17:1251-5. [PMID: 16951564 PMCID: PMC3039124 DOI: 10.1097/01.wnr.0000230500.03330.01] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The pathophysiology of dystonia is still poorly understood. We used diffusion tensor imaging to screen for white matter abnormalities in regions between the basal ganglia and the thalamus in cervical and hand dystonia patients. All patients exhibited an abnormal hemispheric asymmetry in a focal region between the pallidum and the thalamus. This asymmetry was absent 4 weeks after the same patients were treated with intramuscular botulinum toxin injections. These findings represent a new systems-level abnormality in dystonia, which may lead to new insights about the pathophysiology of movement disorders. More generally, these findings demonstrate central nervous system changes following peripheral reductions in muscle activity. This raises the possibility that we have observed activity-dependent white matter plasticity in the adult human brain.
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Affiliation(s)
- Anne J Blood
- Department of Neurology, Massachusetts General Hospital, Charlestown 02129, and Harvard Medical School, Boston, Massachusetts, USA.
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60
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Ali SO, Thomassen M, Schulz GM, Hosey LA, Varga M, Ludlow CL, Braun AR. Alterations in CNS activity induced by botulinum toxin treatment in spasmodic dysphonia: an H215O PET study. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2006; 49:1127-46. [PMID: 17077220 DOI: 10.1044/1092-4388(2006/081)] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Speech-related changes in regional cerebral blood flow (rCBF) were measured using H(2)(15)O positron-emission tomography in 9 adults with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (BTX) injection and 10 age- and gender-matched volunteers without neurological disorders. Scans were acquired at rest and during production of continuous narrative speech and whispered speech. Speech was recorded during scan acquisition for offline quantification of voice breaks, pitch breaks, and percentage aperiodicity to assess correlations between treatment-related changes in rCBF and clinical improvement. Results demonstrated that speech-related responses in heteromodal sensory areas were significantly reduced in persons with ADSD, compared with volunteers, before the administration of BTX. Three to 4 weeks after BTX injection, speech-related responses were significantly augmented in these regions and in left hemisphere motor areas commonly associated with oral-laryngeal motor control. This pattern of responses was most strongly correlated with the objective measures of clinical improvement (decreases in the frequency of voice breaks, pitch breaks, and percentage aperiodicity). These data suggest a pathophysiological model for ADSD in which BTX treatment results in more efficient cortical processing of sensory information, making this information available to motor areas that use it to more effectively regulate laryngeal movements.
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Affiliation(s)
- S Omar Ali
- Language Section, Voice, Speech and Language Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Building 10, Room 8S235A, 10 Center Drive, Bethesda, MD 20892, USA
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Abstract
PURPOSE OF REVIEW The aim of this article is to review current advances in functional magnetic resonance imaging and positron emission tomography of the motor system in parkinsonism and dystonia. RECENT FINDINGS In Parkinson's disease, recent functional magnetic resonance imaging studies have shown that the pattern of regional activity changes in the motor system are strongly modulated by the amount of attention patients pay to task performance. In focal hand dystonia, functional magnetic resonance imaging has disclosed several functional alterations in the basal ganglia in addition to the well-known cortical abnormalities. Neuroimaging has also been successfully used to assess the impact of pharmacological or surgical interventions. In patients with monogenetically inherited parkinsonism or dystonia, positron emission tomography and functional magnetic resonance imaging have opened up exciting possibilities to link molecular biology with functional changes at a systems level. Neuroimaging of genetically defined at-risk populations has shown great potential to study motor reorganization at the preclinical stage and to identify adaptive mechanisms that prevent or delay clinical manifestation. SUMMARY Functional neuroimaging plays a key role in understanding the pathophysiology of parkinsonism and dystonia. A future challenge will be to clarify how these disorders impair the functional integration within the motor system and how these changes in connectivity are influenced by therapeutic interventions.
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Affiliation(s)
- Thilo van Eimeren
- NeuroImage-Nord, Department of Neurology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
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62
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Baur B, Schenk T, Fürholzer W, Scheuerecker J, Marquardt C, Kerkhoff G, Hermsdörfer J. Modified pen grip in the treatment of Writer's Cramp. Hum Mov Sci 2006; 25:464-73. [PMID: 16870291 DOI: 10.1016/j.humov.2006.05.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Writer's Cramp (WC) is a focal, action-related dystonia, which induces hypertonic co-contractions and severely impairs handwriting. One behavioral treatment approach is the handwriting training developed by Mai and Marquardt (1999), [Mai, N., & Marquardt, C. (1999). Schreibtraining in der neurologischen Rehabilitation. In EKN-Materialien für die Rehabilitation. Dortmund: Borgmann] which includes among various motor exercises the use of a modified pen grip (stabilized between index and middle finger). This pen grip has proven particularly successful in clinical practice. The current study aims at elucidating the immediate effects of the modified pen grip on writing in 23 WC patients and 11 healthy controls. All participants wrote a sentence with their usual and also with the modified pen grip. Movement and pressure were recorded with a digitizing tablet. Pressure, movement time for the whole sentence, script size and writing fluency were analyzed. When writing with their usual pen grip, pressure in the WC patients was elevated, and writing speed was decreased compared to healthy controls. Changing over to the modified pen grip reduced the pressure significantly in WC patients and controls, but left other aspects of their writing unaffected. This shows that the use of the modified pen grip is an effective way to normalize pen pressure in WC patients, thereby providing the best conditions for the training of speed and fluency.
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Affiliation(s)
- Barbara Baur
- Clinical Neuropsychology Research Group (EKN), Krankenhaus München-Bogenhausen, Dachauerstrasse 164, 80992 München, Germany.
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63
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Abstract
The pathophysiology and management of writer's cramp is one of the most challenging amongst the various forms of focal dystonias. Frequently, the dystonic postures are confounded by compensatory muscle activity. Correct identification of target muscles for botulinum toxin (BT) injections determines the treatment success. The dosages of different preparations vary, with 1 unit of Botox roughly equalling 3.5 units of Dysport. Electromyographic guided injections yield better results and may also decrease the amount of toxin required. Weakness of target muscles interfering with other non-writing activities is a frequently encountered adverse effect. Studies have shown that BT is a safe long-term therapy option.
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Affiliation(s)
- C P Das
- Department of Neurology, Postgraduate Institute of Medical Education and Research, Chadigarh, India.
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64
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Merello M, Carpintiero S, Cammarota A, Meli F, Leiguarda R. Bilateral mirror writing movements (mirror dystonia) in a patient with writer's cramp: Functional correlates. Mov Disord 2006; 21:683-9. [PMID: 16342284 DOI: 10.1002/mds.20736] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A recent prospective analysis on writer's cramp showed that up to 44.6% of patients in a series of 65 presented mirror dystonia, defined as involuntary movements of the resting hand, abnormal posture, tremor, and jerks occurring while writing with the opposite hand. A clinical case is presented, with videotape evidence of right-handed writer's cramp, with mirror movements elicited while writing using either hand. Functional magnetic resonance imaging studies are compared both to those of a normal patient and to those from a patient with writer's cramp but lacking mirror dystonia. Widespread bilateral activation of cortical motor areas contralateral to the mirror movements in patients with writer's cramp and mirror movements suggests, that bilateral activation of the primary motor cortex may account for the appearance of these mirror movements. Further studies need to be conducted to determine whether mirror movements in dystonic patients appear as a result of loss of intra- and/or interhemispheric cortical inhibition or are simply a consequence of the sustained effort these patients need to exert while writing using a dystonic hand.
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Affiliation(s)
- Marcelo Merello
- Movement Disorders Section, Raul Carrea Institute for Neurological Research FLENI, Buenos Aires, Argentina.
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65
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Singer C, Papapetropoulos S. Adult-onset primary focal foot dystonia. Parkinsonism Relat Disord 2006; 12:57-60. [PMID: 16154790 DOI: 10.1016/j.parkreldis.2005.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 07/18/2005] [Indexed: 11/25/2022]
Abstract
Although primary focal hand dystonia has been well characterized, primary focal foot dystonia in adults has rarely been reported. Our objective was to describe the clinical phenotype and treatment outcomes in patients with primary, adult-onset focal foot dystonia. To this end we conducted a retrospective study of four consecutive patients (59.5+/-13.5 years, range 44-67) diagnosed over a period of 6 years and followed-up for at least 5 years. Focal foot dystonia resulted in variable physical impairment. Anti-dystonic agents were mildly effective whereas botulinum toxin injections provided substantial benefit when used. Focal primary focal foot dystonia seems to be a rare form of focal dystonia with distinct clinical features that may benefit from treatment with botulinum toxin.
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Affiliation(s)
- Carlos Singer
- Department of Neurology, Miller School of Medicine, University of Miami, 1501 NW 9th Avenue, Miami, FL 33136, USA.
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Long CJ, Brown EN, Triantafyllou C, Aharon I, Wald LL, Solo V. Nonstationary noise estimation in functional MRI. Neuroimage 2005; 28:890-903. [PMID: 16129625 DOI: 10.1016/j.neuroimage.2005.06.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 06/28/2005] [Accepted: 06/28/2005] [Indexed: 10/25/2022] Open
Abstract
An important issue in functional MRI analysis is accurate characterisation of the noise processes present in the data. Whilst conventional fMRI noise representations often assume stationarity (or time-invariance) in the noise generating sources, such approaches may serve to suppress important dynamic information about brain function. As an alternative to these fixed temporal assumptions, we present in this paper two time-varying procedures for examining nonstationary noise structure in fMRI data. In the first procedure, we approximate nonstationary behaviour by means of a collection of simple but numerous time-varying parametric models. This is accomplished through the derivation of a locally parametric AutoRegressive (AR) plus drift model which tracks temporal covariance by allowing the model parameters to evolve over time. Before exploring time variation in these parameters, window-widths (bandwidths) that are well suited to the latent time-varying noise structure must be determined. To do this, we employ a bandwidth selection mechanism based on Stein's Unbiased Risk Estimator (SURE) criterion. In the second procedure, we describe the fMRI noise using a nonparametric method based on Functional Data Analysis (FDA). This process generates well-conditioned nonstationary covariance estimates that reflect temporal continuity in the underlying data structure whilst penalizing effective model dimension. We demonstrate both methods on simulated data and investigate the presence of nonstationary noise in resting fMRI data using the whitening capabilities of the locally parametric procedure. We evaluate the comparative behaviour of the stationary and nonstationary AR-based methods on data acquired at 1.5, 3 and 7 T magnetic field strengths and show that incorporation of time variation in the AR parameters leads to an overall decrease in the level of residual structure in the data. The FDA noise modelling technique is formulated within an activation mapping procedure and compared to the SPM (Statistical Parametric Mapping) toolbox on a cognitive face recognition task. Both the SPM and FDA methods show good sensitivity on this task, but we find that inclusion of the nonstationary FDA noise model seems to improve detection power in important task-related medial temporal regions.
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Affiliation(s)
- C J Long
- MGH/MIT/HMS Martinos Center for Biomedical Imaging, Charlestown, MA 02129, USA.
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