Split-belt locomotion in Parkinson's disease links asymmetry, dyscoordination and sequence effect

Publication date: July 2016
Source:Gait & Posture, Volume 48
Author(s): Alfonso Fasano, Christian Schlenstedt, Jan Herzog, Meir Plotnik, Franziska E.M. Rose, Jens Volkmann, Günther Deuschl
BackgroundThe pathophysiology behind gait impairments seen in Parkinson's disease (PD), in particular freezing of gait (FOG), is not fully understood. Here we study the interplay between several gait features related to FOG during different split-belt treadmill (SBTM) conditions.MethodsWe investigated the spatiotemporal properties, the phenomenon of sequence effect and the inter-limb symmetry and temporal coordination of gait during different split-belt conditions in 20 patients with advanced Parkinson's disease and different severities of freezing. Subjects were tested in four belt configurations: tied, split while reducing the velocity of leg with the shorter (worst side reduction, WSR) and longer (best side reduction, BSR) step length, and tied again to measure the after-effect.ResultsWe found that in spite of an improvement of spatial symmetry, the BSR led to a worsening of coordination (i.e. the left-right anti-phased stepping) and an increased sequence effect (i.e. progressive shortening of the step length). By contrast, in spite of a worsened spatial symmetry, WSR improved inter-limbs coordination and reduced the sequence effect. After prolonged split-belt walking gait was differently modulated according to the reduction of the best or worst leg velocity: BSR led to positive after effects in symmetry, bilateral coordination and sequence effect.ConclusionsThese findings support the hypothesis that the irregularity of inter-limb coordination and defective amplitude generation leading to sequence effect might be coupled and result from the same maladaptive motor behavior. Furthermore, our results show that SBTM can be an effective tool to improve parkinsonian gait.



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Repair or Violation Detection? Pre-Attentive Processing Strategies of Phonotactic Illegality Demonstrated on the Constraint of g-Deletion in German

Purpose

Effects of categorical phonotactic knowledge on pre-attentive speech processing were investigated by presenting illegal speech input that violated a phonotactic constraint in German called “g-deletion.” The present study aimed to extend previous findings of automatic processing of phonotactic violations and to investigate the role of stimulus context in triggering either an automatic phonotactic repair or a detection of the violation.

Method

The mismatch negativity event-related potential component was obtained in 2 identical cross-sectional experiments with speaker variation and 16 healthy adult participants each. Four pseudowords were used as stimuli, 3 of them phonotactically legal and 1 illegal. Stimuli were contrasted pairwise in passive oddball conditions and presented binaurally via headphones. Results were analyzed by means of mixed design analyses of variance.

Results

Phonotactically illegal stimuli were found to be processed differently compared to legal ones. Results indicate evidence for both automatic repair and detection of the phonotactic violation depending on the linguistic context the illegal stimulus was embedded in.

Conclusions

These findings corroborate notions that categorical phonotactic knowledge is activated and applied even in the absence of attention. Thus, our findings contribute to the general understanding of sublexical phonological processing and may be of use for further developing speech recognition models.

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The correlation between ECochG parameters and early auditory behavior after cochlear implantation in children

10.3109/14992027.2016.1172392<br/>Konrad Johannes Stuermer

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Barriers to early cochlear implantation

10.1080/14992027.2016.1174890<br/>Shani Dettman

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Influence of stimulation position on the sensitivity for bone conduction hearing aids without skin penetration

10.3109/14992027.2016.1172120<br/>Ivo Dobrev

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Development of Telscreen: a telephone-based speech-in-noise hearing screening test with a novel masking noise and scoring procedure

10.3109/14992027.2016.1172268<br/>Harvey Dillon

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Applying theories of health behaviour and change to hearing health research: Time for a new approach

10.3109/14992027.2016.1161851<br/>Neil S. Coulson

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The correlation between ECochG parameters and early auditory behavior after cochlear implantation in children

10.3109/14992027.2016.1172392<br/>Konrad Johannes Stuermer

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Barriers to early cochlear implantation

10.1080/14992027.2016.1174890<br/>Shani Dettman

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Influence of stimulation position on the sensitivity for bone conduction hearing aids without skin penetration

10.3109/14992027.2016.1172120<br/>Ivo Dobrev

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Development of Telscreen: a telephone-based speech-in-noise hearing screening test with a novel masking noise and scoring procedure

10.3109/14992027.2016.1172268<br/>Harvey Dillon

from #Audiology via ola Kala on Inoreader http://ift.tt/1TiHECE
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Applying theories of health behaviour and change to hearing health research: Time for a new approach

10.3109/14992027.2016.1161851<br/>Neil S. Coulson

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