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Tomáš Sieger
presents
Interactive Dendrograms for R; Eye Movements Study
 
On 2017-03-06 15:30 at E112
 
1) Interactive Dendrograms: The R Packages idendro and idendr0

Hierarchical cluster analysis is a valuable tool for exploring data by
describing their structure using a dendrogram. However, proper
visualization and interactive inspection of the dendrogram are needed
to unlock the information in the data. We describe a new R package,
idendro, that enables the user to inspect dendrograms interactively: to
select and color clusters, to zoom and pan the dendrogram, and to
visualize the clustered data not only in a built-in heat map, but also
in any interactive plot implemented in the cranvas package. A
lightweight version idendr0 with reduced dependencies is also available
from the Comprehensive R Archive Network.

2) Antisaccades and Vergence Abnormalities in Functional Movement
Disorders: A Video-Oculographic Study

Convergence spasm was reported as a common eye movement (EM)
abnormality in patients with functional movement disorders (FMD). We
aimed to analyze horizontal reflexive, volitional and vergence EM in
FMD using video-oculography (VOG). Twenty patients with FMD and 20
matched controls underwent VOG with tasks for prosaccades, antisaccades
and vergence. Mean latency and velocities were analyzed in prosaccades
and vergence. In antisaccades, error rate was evaluated. Clinically
manifested convergence spasm was found only in two patients, however,
FMD patients showed prolonged latencies in divergence EM. Higher error
rate in the antisaccade task and no differences in prosaccades in
comparison to controls were found. Subclinical abnormalities in
vergence EM along with normal reflexive EM are suggestive of explicit
EM control failure in FMD. Consistently with current hypothesis of
attention and response inhibition disorders in FMD, we found an
increased error rate in antisaccades in FMD.
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