Stephan Bohlhalter

Publications of Stephan Bohlhalter

• Bilateral neglect after bihemispheric strokes.

  Authors: Dario Cazzoli, Rahel Schumacher, Uli Baas, René M Müri, Roland Wiest, Stephan Bohlhalter, Christian W Hess, Thomas Nyffeler

  Cortex; a journal devoted to the study of the nervous system and behavior. 04/2012; 48(4):504-8.

• Limb Apraxia in Multiple Sclerosis: Prevalence and Impact on Manual Dexterity and Activities of Daily Living.

  Authors: Christian P Kamm, Mirjam R Heldner, Tim Vanbellingen, Heinrich P Mattle, René Müri, Stephan Bohlhalter

  Archives of physical medicine and rehabilitation. 03/2012;

  Kamm CP, Heldner MR, Vanbellingen T, Mattle HP, Müri R, Bohlhalter S. Limb apraxia in multiple sclerosis: prevalence and impact on manual dexterity and activities of daily living. OBJECTIVE: ToKamm CP, Heldner MR, Vanbellingen T, Mattle HP, Müri R, Bohlhalter S. Limb apraxia in multiple sclerosis: prevalence and impact on manual dexterity and activities of daily living. OBJECTIVE: To evaluate the prevalence and impact of limb apraxia on manual dexterity and activities of daily living (ADLs) in patients with multiple sclerosis (MS). DESIGN: Survey. SETTING: University hospital. PARTICIPANTS: Consecutive patients (N=76) with clinically isolated syndrome, relapsing-remitting multiple sclerosis (RRMS), secondary progressive multiple sclerosis (SPMS) or primary progressive multiple sclerosis (PPMS), Expanded Disability Status Scale (EDSS) score from 0 to 6.5, and aged from 18 to 70 years were included. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Apraxia was assessed by the apraxia screen of TULIA (AST). The relationship of apraxia with ADLs and manual dexterity was evaluated using a dexterity questionnaire and the coin rotation task, respectively. RESULTS: Overall, limb apraxia was found in 26.3% of patients (mean AST score ± SD, 7.3±1.3; cutoff <9). Apraxia was significantly correlated with higher EDSS scores, longer disease duration, and higher age with the EDSS being predictive. Furthermore, patients with SPMS and PPMS were more apraxic than patients with RRMS. Finally, limb apraxia was significantly associated with impaired ADLs and manual dexterity. CONCLUSIONS: Limb apraxia is a frequent and clinically significant symptom contributing to disability in MS. It should therefore be evaluated and possibly treated, particularly in patients with MS reporting manual difficulties in everyday life.

• Impaired pantomime in schizophrenia: Association with frontal lobe function.

  Authors: Sebastian Walther, Tim Vanbellingen, René Müri, Werner Strik, Stephan Bohlhalter

  Cortex; a journal devoted to the study of the nervous system and behavior. 01/2012;

  INTRODUCTION: Gestures are important for nonverbal communication and were shown to be impaired in schizophrenia. Two categories of gestures can be differentiated: pantomime on verbal command andINTRODUCTION: Gestures are important for nonverbal communication and were shown to be impaired in schizophrenia. Two categories of gestures can be differentiated: pantomime on verbal command and imitation of seen gestures. There is evidence that the neural basis of these domains may be distinct, pantomime being critically dependent on prefrontal cortex function. The aim of the study was to investigate gestural deficits in schizophrenia and their association with frontal lobe function and motor performance. METHODS: In 30 schizophrenia patients, gesture performance was assessed by the comprehensive Test of Upper Limb Apraxia (TULIA) using previously determined cut-off scores. The ratings of videotaped gesture performance were blinded. In addition, a battery of rating scales on frontal lobe function, parkinsonism, dyskinesia, catatonia and instrumental measures of gross and fine motor performance were assessed. RESULTS: Pantomime deficits were found in 40% and imitation deficits in 23% of the patients. Patients with gestural deficits had poorer frontal cortex function, more catatonic symptoms, and more severe psychopathology. Furthermore, trends indicated an association with a more chronic course of the illness. Pantomime was linked to frontal lobe function whereas imitation was associated with catatonic symptoms and gross motor performance. CONCLUSIONS: Pantomime is frequently impaired in chronic schizophrenia and may critically depend on motor planning, reflecting a further example of brain disconnectivity in schizophrenia.

• Apraxia in neurorehabilitation: Classification, assessment and treatment.

  Authors: Tim Vanbellingen, Stephan Bohlhalter

  NeuroRehabilitation. 01/2011; 28(2):91-8.

  Apraxia is a higher-order motor disorder impairing the ability to correctly perform skilled, purposive movements as the result of neurological disorders most commonly stroke, dementia and movementApraxia is a higher-order motor disorder impairing the ability to correctly perform skilled, purposive movements as the result of neurological disorders most commonly stroke, dementia and movement disorders. It is increasingly recognised that apraxia negatively influences activities of daily living (ADL). Early diagnosis and treatment should be part of the neurorehabilitation programme. The aim of the present article is to describe the most important subtypes of apraxia such as ideational and ideomotor apraxia as well as their impact on ADL and outcome. Furthermore, the relationship to associated disorders such as aphasia is discussed. Finally, strategies concerning assessment, management and treatment of the disorder are presented.

• Interference with gesture production by theta burst stimulation over left inferior frontal cortex.

  Authors: Stephan Bohlhalter, Tim Vanbellingen, Manuel Bertschi, Pascal Wurtz, Dario Cazzoli, Thomas Nyffeler, Christian W Hess, René Müri

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 12/2010; 122(6):1197-202.

  The traditional view of a predominant inferior parietal representation of gestures has been recently challenged by neuroimaging studies demonstrating that gesture production and discrimination mayThe traditional view of a predominant inferior parietal representation of gestures has been recently challenged by neuroimaging studies demonstrating that gesture production and discrimination may critically depend on inferior frontal lobe function. The aim of the present work was therefore to investigate the effect of transient disruption of these brain sites by continuous theta burst stimulation (cTBS) on gesture production and recognition. Fourteen healthy subjects participated in the study. A repeated measures design was employed with three experimental sessions: baseline (BSL), left inferior parietal (IPL) and inferior frontal (IFG) TBS. Gesture production and recognition was assessed in an off-line approach using a new test of upper limb apraxia (TULIA) and a modified version of postural knowledge test (PKT). TBS of the left IFG significantly lowered total TULIA scores. The effect was even more prominent when contrasted with IPL than with BSL. However, TBS over either stimulation site did not significantly influence PKT measures. The interference of the left inferior frontal cTBS with gesture production emphasizes the role this brain region has in the control of gestures. The study demonstrated that gesture performance is amenable to modulation with TBS.

• Kinematic improvement following Botulinum Toxin-A injection in upper limb spasticity due to stroke.

  Authors: Esteban Fridman, Marcos Crespo, Santiago Gomez Argüello, Lorena Degue, Mirta Villarreal, Stephan Bohlhalter, Lewis Wheaton, Mark Hallett

  Journal of neurology, neurosurgery, and psychiatry. 12/2009;

  Background and purpose: Focal spasticity is a significant motor disorder following stroke. Botulinum Toxin Type-A (BoNT-A) is a useful treatment for it. We evaluated kinematic modifications inducedBackground and purpose: Focal spasticity is a significant motor disorder following stroke. Botulinum Toxin Type-A (BoNT-A) is a useful treatment for it. We evaluated kinematic modifications induced by spasticity, and whether or not there is an improvement following injection of BoNT-A. METHODS: Eight stroke patients with upper limb spasticity, showing a flexor pattern, were evaluated using kinematics before and after focal treatment with BoNT-A. A group of sex and age-matched normal volunteers acted as a control group. RESULTS: Repeated-measure ANOVA showed that stroke patients performed slower in comparison to the control group. Following treatment with BoNT-A there was a significant improvement in kinematics in stroke patients while in the control group performance remained unchanged. CONCLUSIONS: Focal treatment of spasticity with Botulinum Toxin Type-A leads to an adaptive change in the upper limb of spastic stroke patients.

• Left parietal activation related to planning, executing and suppressing praxis hand movements.

  Authors: Lewis Wheaton, Esteban Fridman, Stephan Bohlhalter, Sherry Vorbach, Mark Hallett

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 05/2009;

  OBJECTIVE: We sought to investigate the activity of bilateral parietal and premotor areas during a Go/No Go paradigm involving praxis movements of the dominant hand. METHODS: A sentence was presentedOBJECTIVE: We sought to investigate the activity of bilateral parietal and premotor areas during a Go/No Go paradigm involving praxis movements of the dominant hand. METHODS: A sentence was presented which instructed subjects on what movement to make (S1; for example, "Show me how to use a hammer."). After an 8-s delay, "Go" or "No Go" (S2) was presented. If Go, they were instructed to make the movement described in the S1 instruction sentence as quickly as possible, and continuously until the "Rest" cue was presented 3s later. If No Go, subjects were to simply relax until the next instruction sentence. Event-related potentials (ERP) and event-related desynchronization (ERD) in the beta band (18-22Hz) were evaluated for three time bins: after S1, after S2, and from -2.5 to -1.5s before the S2 period. RESULTS: Bilateral premotor ERP was greater than bilateral parietal ERP after the S2 Go compared with the No Go. Additionally, left premotor ERP was greater than that from the right premotor area. There was predominant left parietal ERD immediately after S1 for both Go and No Go, which was sustained for the duration of the interval between S1 and S2. For both S2 stimuli, predominant left parietal ERD was again seen when compared to that from the left premotor or right parietal area. However, the left parietal ERD was greater for Go than No Go. CONCLUSION: The results suggest a dominant role in the left parietal cortex for planning, executing, and suppressing praxis movements. The ERP and ERD show different patterns of activation and may reflect distinct neural movement-related activities. SIGNIFICANCE: The data can guide further studies to determine the neurophysiological changes occurring in apraxia patients and help explain the unique error profiles seen in patients with left parietal damage.

• Poor dopaminergic response of impaired dexterity in Parkinson's disease: Bradykinesia or limb kinetic apraxia?

  Authors: Andreas Gebhardt, Tim Vanbellingen, Fabio Baronti, Bernd Kersten, Stephan Bohlhalter

  Movement disorders : official journal of the Movement Disorder Society. 09/2008; 23(12):1701-6.

  Patients with Parkinson's disease (PD) often show impaired manual dexterity even when being only minimally bradykinetic, suggesting that they may have limb kinetic apraxia (LKA), that is, a loss ofPatients with Parkinson's disease (PD) often show impaired manual dexterity even when being only minimally bradykinetic, suggesting that they may have limb kinetic apraxia (LKA), that is, a loss of fine motor skill not explained by elemental motor deficits. To explore this dissociation, we investigated the differential dopaminergic responsiveness of dexterity and bradykinesia in PD. Twelve patients with PD (4 women, age 64.4 +/- 8.3, mean + SD) and 12 matched healthy controls (64.8 +/- 8.9) were tested twice in ON vs. OFF and 1st vs. 2nd trial, respectively. A coin rotation (CR) task was applied to assess dexterity and a finger tapping (FT) task to assess bradykinesia. Performance was followed by video recording and analyzed by measuring the frequency of CR and FT during three 10-second periods. Statistical analysis was done by a mixed factorial design with group (PD vs. controls) as between-subject factor and medication (ON- vs. OFF-state or 1st vs. 2nd trial), task (FT vs. CR), and handedness (dominant vs. nondominant) as within-subject factors. In patients with PD, regardless of hand involved, dopaminergic treatment only mildly improved CR performance, in contrast to the strong increase in FT scores (up to the level of controls), as demonstrated by the significant triple interaction of the factors group, medication, and task (F(1,22) = 7.9, P = 0.01; eta(2) = 0.26). Furthermore, CR scores were considerably lower, both in OFF and ON, than in normal controls, pointing to a substantial impairment of dexterity in PD (P < 0.001). In conclusion, impaired manual dexterity showing significantly diminished response to dopaminergic treatment suggests that dextrous deficits in PD are related to LKA rather than bradykinesia.

• Cortico-cortical networks in patients with ideomotor apraxia as revealed by EEG coherence analysis.

  Authors: Lewis A Wheaton, Stephan Bohlhalter, Guido Nolte, Hiroshi Shibasaki, Noriaki Hattori, Esteban Fridman, Sherry Vorbach, Jordan Grafman, Mark Hallett

  Neuroscience letters. 04/2008; 433(2):87-92.

  We sought to determine whether coherent networks which circumvent lesioned cortex are seen in patients with ideomotor apraxia (IMA) while performing tool-use pantomimes. Five normal subjects and fiveWe sought to determine whether coherent networks which circumvent lesioned cortex are seen in patients with ideomotor apraxia (IMA) while performing tool-use pantomimes. Five normal subjects and five patients with IMA (three patients with corticobasal degeneration and two with left hemisphere stroke) underwent 64-channel EEG recording while performing three tool-use pantomimes with their left hand in a self-paced manner. Beta band (20-22 Hz) coherence indicates that normal subjects have a dominant left hemisphere network responsible for praxis preparation, which was absent in patients. Corticobasal degeneration patients showed significant coherence increase between left parietal-right premotor areas. Left hemisphere stroke patients showed significant coherence increases in a right parietofrontal network. The right hemisphere appears to store useable praxis representations in IMA patients with left hemisphere damage.

• Abnormality of motor cortex excitability in peripherally induced dystonia.

  Authors: Stephan Bohlhalter, Fidias E Leon-Sarmiento, Mark Hallett

  Movement disorders : official journal of the Movement Disorder Society. 07/2007; 22(8):1186-9.

  It is widely accepted that peripheral trauma such as soft tissue injuries can trigger dystonia, although little is known about the underlying mechanism. Because peripheral injury only rarely appearsIt is widely accepted that peripheral trauma such as soft tissue injuries can trigger dystonia, although little is known about the underlying mechanism. Because peripheral injury only rarely appears to elicit dystonia, a predisposing vulnerability in cortical motor areas might play a role. Using single and paired-pulse pulse transcranial magnetic stimulation, we evaluated motor cortex excitability of a hand muscle in a patient with peripherally induced foot dystonia, in her brother with craniocervical dystonia, and in her unaffected sister, and compared their results to those from a group of normal subjects. In the patient with peripherally induced dystonia, we found a paradoxical intracortical facilitation at short interstimulus intervals of 3 and 5 milliseconds, at which regular intracortical inhibition (ICI) occurred in healthy subjects. These findings suggest that the foot dystonia may have been precipitated as the result of a preexisting abnormality of motor cortex excitability. Furthermore, the abnormality of ICI in her brother and sister indicates that altered motor excitability may be a hereditary predisposition. The study demonstrates that the paired-pulse technique is a useful tool to assess individual vulnerability, which can be particularly relevant when the causal association between trauma and dystonia is less evident.

• Increased midbrain gray matter in Tourette's syndrome.

  Authors: Gaëtan Garraux, Andrew Goldfine, Stephan Bohlhalter, Alicja Lerner, Takashi Hanakawa, Mark Hallett

  Annals of neurology. 03/2006; 59(2):381-5.

  OBJECTIVE: To investigate cerebral structure in Tourette's syndrome (TS). METHODS: Voxel-based morphometry study of high-resolution MRIs in 31 TS patients compared with 31 controls. RESULTS:OBJECTIVE: To investigate cerebral structure in Tourette's syndrome (TS). METHODS: Voxel-based morphometry study of high-resolution MRIs in 31 TS patients compared with 31 controls. RESULTS: Increased gray matter mainly in the left mesencephalon in 31 TS patients. INTERPRETATION: This result constitutes strong and direct evidence supporting Devinsky's hypothesis (Devinsky O. Neuroanatomy of Gilles de la Tourette's syndrome. Possible midbrain involvement. Arch Neurol 1983;40:508-514) according to which midbrain disturbances play an important pathogenic role in TS.

• The role of the dorsal stream for gesture production.

  Authors: Esteban A Fridman, Ilka Immisch, Takashi Hanakawa, Stephan Bohlhalter, Daniel Waldvogel, Kenji Kansaku, Lewis Wheaton, Tao Wu, Mark Hallett

  NeuroImage. 02/2006; 29(2):417-28.

  Skilled gestures require the integrity of the neural networks involved in storage, retrieval, and execution of motor programs. Premotor cortex and/or parietal cortex lesions frequently produceSkilled gestures require the integrity of the neural networks involved in storage, retrieval, and execution of motor programs. Premotor cortex and/or parietal cortex lesions frequently produce deficits during performance of gestures, transitive more than intransitive. The dorsal stream links object information with object action, suggesting that mechanical knowledge of tool use is stored focally in the brain. Using event-related fMRI, we explored activity during instructed-delay transitive and intransitive hand gestures. The comparison between planning-preparation and execution of gestures demonstrated a temporal rostral to caudal gradient of activation in the ventral premotor cortex (PMv) and inferior to superior gradient of activation in the posterior parietal cortex (PPc). Comparison between transitive and intransitive gestures established a functional specificity within the dorsal stream for mechanical knowledge. Results demonstrate that not only PPc but also the PMv acts in the processing of sensorimotor information during gestures. This might be the substrate underlying selective deficits in ideomotor apraxia patients.

• Synchronization of parietal and premotor areas during preparation and execution of praxis hand movements.

  Authors: Lewis A Wheaton, Guido Nolte, Stephan Bohlhalter, Esteban Fridman, Mark Hallett

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 07/2005; 116(6):1382-90.

  OBJECTIVE: We sought to determine temporal patterns of functional connectivity between the parietal, premotor, and motor cortices during preparation and execution of praxis hand movements. METHODS:OBJECTIVE: We sought to determine temporal patterns of functional connectivity between the parietal, premotor, and motor cortices during preparation and execution of praxis hand movements. METHODS: Normal subjects were instructed to perform six transitive (tool use) and intransitive (communicative gesture) self-paced pantomimes with the right hand while recording 64-channel electroencephalography (EEG) and electromyography (EMG) from right thumb and forearm flexors. Focusing on corticocortical coherence, we explored the time-course of synchronously active parietal and premotor circuits involved in these motor tasks. Trials were marked for EMG onset and averaged across subjects to determine changes in coherence relative to baseline between parietal, premotor, and motor areas. RESULTS: Coherence of homologous electrode pairs was similar when comparing transitive and intransitive movements. During preparation, beta band (18-22 Hz) coherence was maximal between electrodes over the left parietal lobe and left premotor electrodes. Additionally during preparation, the premotor area showed high coherence to the motor hand area and the parietal cortex. Electrodes over the supplementary motor area also showed coherence to the motor and parietal, but not the premotor area. Before and during execution, a second peak of high coherence increase was present in each area that demonstrated coherence increases during preparation. There was no coherence increase between parietal and motor areas. Coherence rapidly diminished 1.5-2.0 s after movement onset. CONCLUSIONS: Patterns of increased corticocortical coupling within a parietal, premotor, and motor network are present during preparation and execution of praxis movements. SIGNIFICANCE: This study adds to evidence that parietofrontal networks may be critical for integrating preparatory and motor-related activity for praxis movements.

• Synchronization of parietal and premotor areas during preparation and execution of praxis hand movements

  Authors: Lewis A. Wheaton, Guido Nolte, Stephan Bohlhalter, Esteban Fridman, Mark Hallett

  Clinical Neurophysiology.

  ObjectiveWe sought to determine temporal patterns of functional connectivity between the parietal, premotor, and motor cortices during preparation and execution of praxis hand movements.MethodsNormalObjectiveWe sought to determine temporal patterns of functional connectivity between the parietal, premotor, and motor cortices during preparation and execution of praxis hand movements.MethodsNormal subjects were instructed to perform six transitive (tool use) and intransitive (communicative gesture) self-paced pantomimes with the right hand while recording 64-channel electroencephalography (EEG) and electromyography (EMG) from right thumb and forearm flexors. Focusing on corticocortical coherence, we explored the time-course of synchronously active parietal and premotor circuits involved in these motor tasks. Trials were marked for EMG onset and averaged across subjects to determine changes in coherence relative to baseline between parietal, premotor, and motor areas.ResultsCoherence of homologous electrode pairs was similar when comparing transitive and intransitive movements. During preparation, beta band (18–22 Hz) coherence was maximal between electrodes over the left parietal lobe and left premotor electrodes. Additionally during preparation, the premotor area showed high coherence to the motor hand area and the parietal cortex. Electrodes over the supplementary motor area also showed coherence to the motor and parietal, but not the premotor area. Before and during execution, a second peak of high coherence increase was present in each area that demonstrated coherence increases during preparation. There was no coherence increase between parietal and motor areas. Coherence rapidly diminished 1.5–2.0 s after movement onset.ConclusionsPatterns of increased corticocortical coupling within a parietal, premotor, and motor network are present during preparation and execution of praxis movements.SignificanceThis study adds to evidence that parietofrontal networks may be critical for integrating preparatory and motor-related activity for praxis movements.