<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Aptos;
panose-1:2 11 0 4 2 2 2 2 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
font-size:11.0pt;
font-family:"Aptos",sans-serif;
mso-ligatures:standardcontextual;
mso-fareast-language:EN-US;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:11.0pt;
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:70.85pt 70.85pt 70.85pt 70.85pt;}
div.WordSection1
{page:WordSection1;}
--></style>
</head>
<body lang="NL" link="#467886" vlink="#96607D" style="word-wrap:break-word">
<div class="WordSection1">
<p><span lang="EN-US" style="font-size:11.0pt;color:black">Dear FieldTrip Support,<o:p></o:p></span></p>
<p style="caret-color: rgb(0, 0, 0);font-variant-caps: normal;orphans: auto;text-align:start;widows: auto;-webkit-text-stroke-width: 0px;word-spacing:0px">
<span lang="EN-US" style="font-size:11.0pt;color:black">I am reaching out regarding a question I have encountered while using FieldTrip for preprocessing.<o:p></o:p></span></p>
<p style="caret-color: rgb(0, 0, 0);font-variant-caps: normal;orphans: auto;text-align:start;widows: auto;-webkit-text-stroke-width: 0px;word-spacing:0px">
<span lang="EN-US" style="font-size:11.0pt;color:black">I am working on PSG analysis where sleep stages have already been marked (with markers for each sleep event, every 30 seconds). I have epoched the data into 30-second segments based on these markers, as
well as into 5 and 3-second segments to test artifact detection and evaluate the percentage of data that would be lost. This choice was driven by the need for complete trial rejection upon artifact detection. The planned analyses include frequency domain analysis,
time-frequency analysis, and examining specific characteristics of EEG.<o:p></o:p></span></p>
<p><span lang="EN-US" style="font-size:11.0pt;color:black">As I delve deeper into specific analyses such as K-complex and sleep spindle detection, I have noticed that different studies use varying segment lengths to detect these events effectively. K-complex
analyses often adhere to AASM criteria for sleep stages (20 or 30-second segments). Segmenting entire trials of 30 seconds and rejecting them outright could potentially discard valuable data.<o:p></o:p></span></p>
<p style="caret-color: rgb(0, 0, 0);font-variant-caps: normal;orphans: auto;text-align:start;widows: auto;-webkit-text-stroke-width: 0px;word-spacing:0px">
<span lang="EN-US" style="font-size:11.0pt;color:black">If I am correct, FieldTrip operates under the premise of segmenting data, and once segmented, the data cannot be recombined into a continuous form or re-epoched. This has left me uncertain about how to
proceed with future analyses that require other segment lengths. It seems imperative that such analyses could also be conducted on a continuous scale.<o:p></o:p></span></p>
<p style="caret-color: rgb(0, 0, 0);font-variant-caps: normal;orphans: auto;text-align:start;widows: auto;-webkit-text-stroke-width: 0px;word-spacing:0px">
<span lang="EN-US" style="font-size:11.0pt;color:black">My concern is primarily about the impact of segment length choice on subsequent analyses. Would different segment lengths significantly affect the outcomes of analyses such as event detection or spectral
analysis? How can I ensure that my choice of segment length aligns well with the requirements of these analyses?<o:p></o:p></span></p>
<p><span lang="EN-US" style="font-size:11.0pt;color:black">I would greatly appreciate any insights, advice, or best practices regarding this matter. If there are specific tools or methodologies within FieldTrip or related software that could address these concerns,
I would be eager to learn more about them.<o:p></o:p></span></p>
<p class="MsoNormal" style="caret-color: rgb(0, 0, 0);font-variant-caps: normal;orphans: auto;text-align:start;widows: auto;-webkit-text-stroke-width: 0px;word-spacing:0px">
<span lang="EN-US">Thank you in advance for your assistance. <br>
<br>
Kind regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Sophie Schubert<o:p></o:p></span></p>
</div>
<!-- --><hr>
<p><font size="-2" face="arial" color="black"><i>
De informatie opgenomen in dit bericht kan vertrouwelijk zijn en is
uitsluitend bestemd voor de geadresseerde. Indien u dit bericht onterecht
ontvangt, wordt u verzocht de inhoud niet te gebruiken en de afzender direct
te informeren door het bericht te retourneren. Het Universitair Medisch
Centrum Utrecht is een publiekrechtelijke rechtspersoon in de zin van de W.H.W.
(Wet Hoger Onderwijs en Wetenschappelijk Onderzoek) en staat geregistreerd bij
de Kamer van Koophandel voor Midden-Nederland onder nr. 30244197.
</i></font></p>
<p><font size="-2" face="arial" color="green"><i>
Denk s.v.p aan het milieu voor u deze e-mail afdrukt.
</i></font></p>
<hr>
<p><font size="-2" face="arial" color="black"><i>
This message may contain confidential information and is intended
exclusively for the addressee. If you receive this message
unintentionally, please do not use the contents but notify the sender
immediately by return e-mail. University Medical Center Utrecht is a legal
person by public law and is registered at the Chamber of Commerce for
Midden-Nederland under no. 30244197.
</i></font></p>
<p><font size="-2" face="arial" color="green"><i>
Please consider the environment before printing this e-mail.
</i></font></p>
</body>
</html>