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Rennig J.,University of Tübingen | Karnath H.-O.,University of Tübingen | Karnath H.-O.,University of South Carolina | Huberle E.,University of Tübingen | Huberle E.,Neurology and Neurorehabilitation Center
Frontiers in Human Neuroscience | Year: 2013

Visual perception depends on the visual context and is likely to be influenced by size constancy, which predicts a size and distance invariant perception of objects. However, size constancy can also result in optical illusions that allow the manipulation of the perceived size. We thus asked whether the integration of local elements into a global object can be influenced by manipulations of the visual context and size constancy? A set of stimuli was applied in healthy individuals that took advantage of the 'Kanizsa' illusion, in which three circles with open wedges oriented towards a center point are placed to form an illusionary perception of a triangle. In addition, a 3D-perspective view was implemented in which the global target ('Kanizsa' triangle) was placed in combination with several distractor circles either in a close or a distant position. Subjects were engaged in a global recognition task on the location of the 'Kanizsa' triangle. Global recognition of 'Kanizsa' triangles improved with a decreasing length of the illusory contour. Interestingly, recognition of 'Kanizsa' triangles decreased when they were perceived as if they were located further away. We conclude that the integration of local elements into a global object is dependent on the visual context and dominated by size constancy. © 2013 Rennig, Karnath and Huberle.


Rennig J.,University of Tübingen | Bilalic M.,University of Tübingen | Huberle E.,University of Tübingen | Huberle E.,Neurology and Neurorehabilitation Center | And 3 more authors.
Frontiers in Human Neuroscience | Year: 2013

In a recent neuroimaging study the comparison of intact vs. disturbed perception of global gestalt indicated a significant role of the temporo-parietal junction (TPJ) in the intact perception of global gestalt (Huberle and Karnath, 2012). This location corresponded well with the areas known to be damaged or impaired in patients with simultanagnosia after stroke or due to neurodegenerative diseases. It was concluded that the TPJ plays an important role in the integration of individual items to a holistic percept. Thus, increased BOLD signals should be found in this region whenever a task calls for the integration of multiple visual items. Behavioral experiments in chess experts suggested that their superior skills in comparison to chess novices are partly based on fast holistic processing of chess positions with multiple pieces. We thus analyzed BOLD data from four fMRI studies that compared chess experts with chess novices during the presentation of complex chess-related visual stimuli (Bilalić et al., 2010, 2011a,b, 2012). Three regions of interests were defined by significant TPJ clusters in the abovementioned study of global gestalt perception (Huberle and Karnath, 2012) and BOLD signal amplitudes in these regions were compared between chess experts and novices. These cross-paradigm ROI analyses revealed higher signals at the TPJ in chess experts in comparison to novices during presentations of complex chess positions. This difference was consistent across the different tasks in five independent experiments. Our results confirm the assumption that the TPJ region identified in previous work on global gestalt perception plays an important role in the processing of complex visual stimulus configurations. © 2013 Rennig, Bilalić, Huberle, Karnath and Himmelbach.


Ritzinger B.,University of Tübingen | Huberle E.,University of Tübingen | Huberle E.,Neurology and Neurorehabilitation Center | Karnath H.-O.,University of Tübingen | Karnath H.-O.,University of South Carolina
PLoS ONE | Year: 2012

While early and higher visual areas along the ventral visual pathway in the inferotemporal cortex are critical for the recognition of individual objects, the neural representation of human perception of complex global visual scenes remains under debate. Stroke patients with a selective deficit in the perception of a complex global Gestalt with intact recognition of individual objects - a deficit termed simultanagnosia - greatly helped to study this question. Interestingly, simultanagnosia typically results from bilateral lesions of the temporo-parietal junction (TPJ). The present study aimed to verify the relevance of this area for human global Gestalt perception. We applied continuous theta-burst TMS either unilaterally (left or right) or bilateral simultaneously over TPJ. Healthy subjects were presented with hierarchically organized visual stimuli that allowed parametrical degrading of the object at the global level. Identification of the global Gestalt was significantly modulated only for the bilateral TPJ stimulation condition. Our results strengthen the view that global Gestalt perception in the human brain involves TPJ and is co-dependent on both hemispheres. © 2012 Ritzinger et al.


Walther S.,University of Bern | Stegmayer K.,University of Bern | Sulzbacher J.,University of Bern | Vanbellingen T.,University of Bern | And 5 more authors.
Schizophrenia Bulletin | Year: 2015

Schizophrenia patients are severely impaired in nonverbal communication, including social perception and gesture production. However, the impact of nonverbal social perception on gestural behavior remains unknown, as is the contribution of negative symptoms, working memory, and abnormal motor behavior. Thus, the study tested whether poor nonverbal social perception was related to impaired gesture performance, gestural knowledge, or motor abnormalities. Forty-six patients with schizophrenia (80%), schizophreniform (15%), or schizoaffective disorder (5%) and 44 healthy controls matched for age, gender, and education were included. Participants completed 4 tasks on nonverbal communication including nonverbal social perception, gesture performance, gesture recognition, and tool use. In addition, they underwent comprehensive clinical and motor assessments. Patients presented impaired nonverbal communication in all tasks compared with controls. Furthermore, in contrast to controls, performance in patients was highly correlated between tasks, not explained by supramodal cognitive deficits such as working memory. Schizophrenia patients with impaired gesture performance also demonstrated poor nonverbal social perception, gestural knowledge, and tool use. Importantly, motor/frontal abnormalities negatively mediated the strong association between nonverbal social perception and gesture performance. The factors negative symptoms and antipsychotic dosage were unrelated to the nonverbal tasks. The study confirmed a generalized nonverbal communication deficit in schizophrenia. Specifically, the findings suggested that nonverbal social perception in schizophrenia has a relevant impact on gestural impairment beyond the negative influence of motor/frontal abnormalities. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.


Heldner M.R.,University of Bern | Vanbellingen T.,University of Bern | Bohlhalter S.,Neurology and Neurorehabilitation Center | Mattle H.P.,University of Bern | And 2 more authors.
Physical Therapy | Year: 2014

Background. Impaired manual dexterity is frequent and disabling in people with multiple sclerosis (MS). Therefore, convenient, quick, and validated tests for manual dexterity in people with MS are needed.Objective. The aim of this study was to validate the Coin Rotation Task (CRT) for examining manual dexterity in people with MS.Design. This was a cross-sectional study.Methods. A total of 101 outpatients with MS were assessed with the CRT, the Expanded Disability Status Scale (EDSS), the Scale for the Assessment and Rating of Ataxia (SARA), and the Modified Ashworth Scale (MAS); muscle strength and sensory deficits of the hands were noted. The concurrent validity and diagnostic accuracy of the CRT were determined by comparison with the 9-Hole Peg Test (9HPT). Construct validity was determined by comparison with a valid dexterity questionnaire. Multiple regression analyses were done to explore correlations of the CRT with the EDSS, SARA, MAS, muscle strength, and sensory deficits.Results. The CRT correlated significantly with the 9HPT (r=.73, P<.0001), indicating good concurrent validity. The cutoff values for the CRT relative to the 9HPT were 18.75 seconds for the dominant hand (sensitivity=81.5%, specificity=80.0%) and 19.25 seconds for the nondominant hand (sensitivity=90.3%, specificity= 81.8%); these values indicated good diagnostic accuracy. Furthermore, the CRT correlated significantly with the dexterity questionnaire (r=-.49, P<.0001), indicating moderate construct validity. Multiple regression analyses revealed that the EDSS was the strongest predictor for impaired dexterity.Limitations. Most of the people examined had relapsing-remitting MS and EDSS scores of up to 7.Conclusions. This study validated the CRT as a test that can be used easily and quickly to evaluate manual dexterity in people with MS. © 2014 American Physical Therapy Association.


Vanbellingen T.,Neurology and Neurorehabilitation Center | Vanbellingen T.,University of Bern | Kamm C.P.,University of Bern
Seminars in Neurology | Year: 2016

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system and the most common cause of nontraumatic disability in young adults. It is a heterogeneous disease associated with long-term disability, negatively influencing quality of life. Disease-modifying pharmacological therapies may decrease activity and progression of the disease, and symptomatic pharmacological treatments may reduce complaints to a certain extent; however, MS patients mostly still suffer from several neurologic deficits in the course of their disease. Consequently, specific comprehensive nonpharmacological rehabilitation interventions are needed to reduce disability to obtain better independence in activities of daily living, resulting in an optimal quality of life. Here the authors give an overview of the main sensorimotor symptoms in MS. Some of the most commonly used standardized outcome assessments are presented, and existing evidence-based motor rehabilitation strategies are described. © 2016 by Thieme Medical Publishers, Inc.


PubMed | Neurology and Neurorehabilitation Center and University of Bern
Type: Journal Article | Journal: Seminars in neurology | Year: 2016

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system and the most common cause of nontraumatic disability in young adults. It is a heterogeneous disease associated with long-term disability, negatively influencing quality of life. Disease-modifying pharmacological therapies may decrease activity and progression of the disease, and symptomatic pharmacological treatments may reduce complaints to a certain extent; however, MS patients mostly still suffer from several neurologic deficits in the course of their disease. Consequently, specific comprehensive nonpharmacological rehabilitation interventions are needed to reduce disability to obtain better independence in activities of daily living, resulting in an optimal quality of life. Here the authors give an overview of the main sensorimotor symptoms in MS. Some of the most commonly used standardized outcome assessments are presented, and existing evidence-based motor rehabilitation strategies are described.


PubMed | Neurology and Neurorehabilitation Center, University of Bern and University of Fribourg
Type: Journal Article | Journal: Cerebrovascular diseases extra | Year: 2016

Screening of aphasia in acute stroke is crucial for directing patients to early language therapy. The Language Screening Test (LAST), originally developed in French, is a validated language screening test that allows detection of a language deficit within a few minutes. The aim of the present study was to develop and validate two parallel German versions of the LAST.The LAST includes subtests for naming, repetition, automatic speech, and comprehension. For the translation into German, task constructs and psycholinguistic criteria for item selection were identical to the French LAST. A cohort of 101 stroke patients were tested, all of whom were native German speakers. Validation of the LAST was based on (1) analysis of equivalence of the German versions, which was established by administering both versions successively in a subset of patients, (2) internal validity by means of internal consistency analysis, and (3) external validity by comparison with the short version of the Token Test in another subset of patients.The two German versions were equivalent as demonstrated by a high intraclass correlation coefficient of 0.91. Furthermore, an acceptable internal structure of the LAST was found (Cronbachs = 0.74). A highly significant correlation (r = 0.74, p < 0.0001) between the LAST and the short version of the Token Test indicated good external validity of the scale.The German version of the LAST, available in two parallel versions, is a new and valid language screening test in stroke.


PubMed | Neurology and Neurorehabilitation Center and University of Bern
Type: | Journal: NeuroImage. Clinical | Year: 2016

Diffusion tensor imaging (DTI) studies have provided evidence of widespread white matter (WM) abnormalities in schizophrenia. Although these abnormalities appear clinically significant, the relationship to specific clinical symptoms is limited and heterogeneous. This study examined the association between WM microstructure and the severity of the five main DSM-5 schizophrenia symptom dimensions. DTI was measured in forty patients with schizophrenia spectrum disorders. Using Tract-Based Spatial Statistics controlling for age, gender and antipsychotic dosage, our analyses revealed significant negative relationships between WM microstructure and two DSM-5 symptom dimensions: Whereas abnormal psychomotor behavior was particularly related to WM of motor tracts, negative symptoms were associated with WM microstructure of the prefrontal and right temporal lobes. However, we found no associations between WM microstructure and delusions, hallucinations or disorganized speech. These data highlight the relevance of characteristic WM disconnectivity patterns as markers for negative symptoms and abnormal psychomotor behavior in schizophrenia and provide evidence for relevant associations between brain structure and aberrant behavior.


PubMed | VU University Amsterdam, University of Bern and Neurology and Neurorehabilitation Center
Type: | Journal: Parkinsonism & related disorders | Year: 2016

Patients with Parkinsons disease exhibit disturbed dexterity. Validated self-reported outcomes for dexterity in Parkinsons disease are lacking. The aim of this study was to investigate the reliability, content and construct validity of a new Dexterity Questionnaire 24.One hundred and three patients with Parkinsons disease completed the Dexterity Questionnaire 24 (score range 24-96), at baseline and four weeks later. The internal consistency was determined. Test-retest reliability was assessed in a subgroup (N=44). Standard error of measurements and the minimal detectable change were defined. The construct validity was examined in the whole group (N=103). Floor and ceiling effects were investigated.The internal consistency of the Dexterity Questionnaire 24 was high (=0.91). High test-retest reliability was found (Intra Class Correlation Coefficient=0.91, Confidence interval: 0.84-0.95). Standard error of measurement was 2.9 and minimal detectable change was 8 points. (i.e., 11%). Good structural, convergent and divergent validity of the Dexterity questionnaire 24 was found (r=0.73 with Activities of Daily Living-subscale of the Parkinsons Disease Questionnaire-39, and r=0.66, and r=0.50, p-values all<0.0001, respectively with the subscales II and III of the Movement Disorders Society-Unified Parkinson Disease Rating Scale). Low not significant correlations were found between the Dexterity Questionnaire 24 and the subscales stigma and social support (r=0.20, and r=0.14 respectively). No floor or ceiling effects were found for the total Dexterity Questionnaire 24.The Dexterity Questionnaire 24 is valid and reliable for evaluating dexterity in patients with Parkinsons disease.

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