scholarly journals Trial Length

2020 ◽  
Author(s):  
Keyword(s):  
Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Francisco A Ponce ◽  
Dakota Graham ◽  
Margaret Lambert ◽  
Zaman Mirzadeh

Abstract INTRODUCTION Spinal cord stimulation (SCS) is commonly used to treat various forms of chronic pain. For some patient, the initial benefit is short lived and they return for device removal. The aims of this study are to identify reasons for SCS explantation and to analyze the circumstances of implantation to identify improvement opportunities for appropriate patient selection and prediction of successful clinical response to the therapy. METHODS This is a retrospective review of 178 patients who underwent SCS explantation over the past 9 yr. RESULTS The most common reason for explantation was a lack of efficacy. Of the 178 patients that received explantation, 141 (79%) indicated that lack of efficacy played a role, 31 (17%) discomfort, 20 (11%) side effects, 22 (12.4%) infection, and 24 (13.5%) expressed the need for an MRI. More than one factor prompted explantation for 33% of these patients (n = 58). A diagnosis of various types of chronic pain without failed back surgery syndrome (FBSS) was the most common diagnosis made up 63% (n = 72/115) of explants, while patients with FBSS made up 37% (n = 43/115). The average SCS trial duration of patients receiving explants was 5.016 d. When comparing the average duration of a permanent SCS implant with the length of a SCS trial, a shorter trial length corresponded with a longer permanent implant duration. SCS trials lasting less than and greater than or equal to five days resulted in an average permanent implant duration of 36.5 mo (n = 25) and 20 mo (n = 38), respectively (alpha = 0.05, P = .0166). CONCLUSION Identifying opportunities for more appropriate patient selection for SCS will increase success rate of the therapy and reduce the number of explants. This may be possible through closer consideration of pain presentation and surgical history, as well as a re-evaluation of trialing methods for SCS.


1998 ◽  
Vol 12 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Daniel L Drane ◽  
David W Loring ◽  
Gregory P Lee ◽  
Kimford J Meador

1967 ◽  
Vol 24 (1) ◽  
pp. 159-166 ◽  
Author(s):  
Harvey A. Taub ◽  
Richard A. Monty ◽  
Kenneth R. Laughery

Ss were required to keep track of the number of occurrences of each of four different letters (categories) presented sequentially as a function of the total number of letters presented (trial length), the rate of presentation, and the two components which, when combined, constitute the rate, namely, stimulus on-time and the interstimulus interval or off-time. In general, performance varied inversely with trial length and rate of presentation. Of greater importance, however, was the complex interaction between the rate of presentation and the components of that rate. At the fastest rate, performance was relatively invariant as a function of these components; at intermediate rates the shortest on-time led to the best performance, while at the slowest rate the shortest on-time led to the poorest performance. The observed results are explained primarily in terms of the time available for rehearsal.


2017 ◽  
Author(s):  
R.A Seymour ◽  
G. Rippon ◽  
K. Kessler

1.AbstractThere is increasing interest in understanding how the phase and amplitude of distinct neural oscillations might interact to support dynamic communication within the brain. In particular, previous work has demonstrated a coupling between the phase of low frequency oscillations and the amplitude (or power) of high frequency oscillations during certain tasks, termed phase amplitude coupling (PAC). For instance, during visual processing in humans, PAC has been reliably observed between ongoing alpha (8-13Hz) and gamma-band (>40Hz) activity. However, the application of PAC metrics to electrophysiological data can be challenging due to numerous methodological issues and lack of coherent approaches within the field. Therefore, in this article we outline the various analysis steps involved in detecting PAC, using an openly available MEG dataset from 16 participants performing an interactive visual task. Firstly, we localised gamma and alpha-band power using the Fieldtrip toolbox, and extracted time courses from area V1, defined using a multimodal parcellation scheme. These V1 responses were analysed for changes in alpha-gamma PAC, using four common algorithms. Results showed an increase in gamma (40-100Hz) - alpha (7-13Hz) PAC in response to the visual grating stimulus, though specific patterns of coupling were somewhat dependent upon the algorithm employed. Additionally, post-hoc analyses showed that these results were not driven by the presence of non-sinusoidal oscillations, and that trial length was sufficient to obtain reliable PAC estimates. Finally, throughout the article, methodological issues and practical guidelines for ongoing PAC research will be discussed.


2010 ◽  
Vol 38 (3) ◽  
pp. 606-627 ◽  
Author(s):  
NIVEDITA MANI ◽  
KIM PLUNKETT

ABSTRACTChildren look longer at a familiar object when presented with either correct pronunciations or small mispronunciations of consonants in the object's label, but not following larger mispronunciations. The current article examines whether children display a similar graded sensitivity to different degrees of mispronunciations of the vowels in familiar words, by testing children's sensitivity to 1-feature, 2-feature and 3-feature mispronunciations of the vowels of familiar labels: Children aged 1 ; 6 did not show a graded sensitivity to vowel mispronunciations, even when the trial length was increased to allow them more time to form a response. Two-year-olds displayed a robust sensitivity to increases in vowel mispronunciation size, differentiating between small and large mispronunciations. While this suggests that early lexical representations contain information about the features contributing to vocalic identity, we present evidence that this graded sensitivity is better explained by the acoustic characteristics of the different mispronunciation types presented to children.


2020 ◽  
Author(s):  
Emma James ◽  
Gabrielle Ong ◽  
Lisa Henderson ◽  
Aidan J Horner

Event memories are characterised by the holistic retrieval of their constituent elements. Studies show that memory for individual event elements (e.g., person, object, and location) are statistically related to each other, and that the same associative memory structure can be formed by learning all pairwise associations across separated encoding contexts (person-object, person-location, object-location). Counter to previous studies that have shown no differences in holistic retrieval between simultaneously and separately encoded event elements, adults did not show evidence of holistic retrieval from separately encoded event elements when using a similar paradigm adapted for children (Experiment 1). We conducted a further five online experiments to explore the conditions under which holistic retrieval emerges following separated encoding of within-event associations, testing for influences of trial length (Experiment 2), the number of events learned (Experiment 3a), and stimulus presentation format (Experiments 3b, 4a, 4b). Presentation of written words was optimal for integrating elements across encoding trials, whereas the addition of spoken words disrupted integration across separately presented associations. Use of picture stimuli also produced effect sizes smaller than those of previously published research. We discuss the ways in which memory integration processes may be disrupted by these differences in presentation format. The findings have practical implications for the utility of this paradigm across research and learning contexts.


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