[Eeglablist] eeglablist Digest, Vol 132, Issue 16

[Isaiah Innis]

Specifically, NetStations versions 4.3.1 and earlier are unaffected.
The linked functions ask for the NetStation version, to prevent adjusting a
file that does not need correction.

Thank you,

2015-10-14 12:56 GMT-04:00 Ghislaine Dehaene <gdehaene at gmail.com>:

> There is normally no problem for NA200 and for NA 300 amps but combined
> with old versions of the netstation, which is my situation. We have
> confirmed EGI's reassurance with real measures using an oscilloscope but if
> you are worried for your specific configuration you should directly ask EGI
> Best regards
>
> 2015-10-13 21:54 GMT+02:00 Isaiah Innis <isainnis at umail.iu.edu>:
>
>> The functions I created reflect the revised notice, which as you noted
>> affects the NA 300. They ask the user for their NetStation version number
>> and determine the correct adjustment based on what is entered.
>>
>> Thank you,
>>
>> 2015-10-13 15:00 GMT-04:00 <eeglablist-request at sccn.ucsd.edu>:
>>
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>>> Today's Topics:
>>>
>>>    1. Re: Correct for EGI latency error functions (Makoto Miyakoshi)
>>>
>>>
>>> ---------- Mensaje reenviado ----------
>>> From: Makoto Miyakoshi <mmiyakoshi at ucsd.edu>
>>> To: Kay Sung <ksung3 at jhmi.edu>
>>> Cc: "eeglablist at sccn.ucsd.edu" <eeglablist at sccn.ucsd.edu>
>>> Date: Tue, 13 Oct 2015 09:43:19 -0700
>>> Subject: Re: [Eeglablist] Correct for EGI latency error functions
>>> Dear Kay,
>>>
>>> Thank you for sharing information. This is very important!
>>>
>>> Makoto
>>>
>>> On Mon, Oct 12, 2015 at 6:09 AM, Kay Sung <ksung3 at jhmi.edu> wrote:
>>>
>>>> Regarding the latency issue, there were actually two announcements
>>>> about the latency issue from EGI (they are attached below).
>>>>
>>>> The original notice says that there was a significant timing delay in
>>>> most of Net Amp models but later they changed it.
>>>>
>>>> I don’t know Isaiah’s codes reflect the most recent announcement from
>>>> EGI.
>>>>
>>>> In their second announcement, EGI said that they found latency delay
>>>> only in NetAmp 300 model with some specific versions of Netstation.
>>>>
>>>>
>>>>
>>>> See below.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *** Original announcement ****
>>>>
>>>>
>>>>
>>>>
>>>> *Electrical Geodesics, Inc. Advisory Notice: Anti-Alias Filter Effects
>>>> on EEG Timing*
>>>>
>>>> This advisory notice is to alert users of EGI’s GES 300 and 400 series
>>>> amplifiers to the delay of EEG data inherent in the anti-aliasing filters
>>>> of these amplifiers. These delay values have not been effectively
>>>> communicated to EGI customers and need to be considered when aligning
>>>> events (such as events generated from E-Prime or from digital inputs) to
>>>> the EEG.
>>>>
>>>> The digital Finite Impulse Response filters used prior to A/D
>>>> conversion delay the EEG by a fixed interval. This interval is known for
>>>> each sampling rate and amplifier model:
>>>>
>>>>
>>>> *Sampling Rate*
>>>>
>>>> *NA 300*
>>>>
>>>> *NA 400*
>>>>
>>>> *NA 405*
>>>>
>>>> *NA 410*
>>>>
>>>> 1000 s/s
>>>>
>>>> 8 ms
>>>>
>>>> 36 ms
>>>>
>>>> 36 ms
>>>>
>>>> 13 ms
>>>>
>>>> 500 s/s
>>>>
>>>> 18 ms
>>>>
>>>> 66 ms
>>>>
>>>> 66 ms
>>>>
>>>> 34 ms
>>>>
>>>> 250 s/s
>>>>
>>>> 36 ms
>>>>
>>>> 112 ms
>>>>
>>>> 112 ms
>>>>
>>>> 76 ms
>>>>
>>>> 125 s/s
>>>>
>>>> 72 ms
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Without adjustment, the EEG is delayed with respect to real time and to
>>>> event markers that are aligned with real time. This delay does not affect
>>>> timing of events manually entered by the user with respect to the EEG
>>>> during acquisition.
>>>>
>>>> Particularly for the Net Amps 400, 405, and 410 models at lower
>>>> sampling rates, the delays may be significant in considering EEG and ERP
>>>> timing. To adjust for this delay, users must add a positive value in the
>>>> “Offset Segment” field in the segmentation tool, in addition to E-Prime
>>>> Event or digital input event (DIN) offsets.
>>>>
>>>> This adjustment is only required for real time events that are recorded
>>>> during acquisition. Events entered during review or from the operations of
>>>> tools after data acquisition are already aligned correctly with the EEG.
>>>>
>>>> To make the delays clear to each user, both the EGI technical manuals
>>>> and EGI Support training will be modified to underscore the importance of
>>>> including these delays in the event alignment and segmentation process. In
>>>> addition, the Net Station software (version 5.1.1) will provide an option
>>>> for automatic adjustment.
>>>>
>>>>
>>>> <http://cts.vresp.com/c/?ElectricalGeodesicsI/25e92832cf/6774d3b846/1bb8b10916/utm_content=gfrishkoff%40gsu.edu&utm_source=VerticalResponse&utm_medium=Email&utm_term=&utm_campaign=Advisory%20Notice%20-%20Anti-Alias%20Filter%20Effects%20on%20EEG%20Timing>Please
>>>> contact EGI support <supportteam at egi.com> for any questions.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *** Second announcement ****
>>>>
>>>>
>>>>
>>>>
>>>> *Electrical Geodesics, Inc. Update to Anti-Alias Filter Effects on EEG
>>>> Timing Advisory Notice*
>>>>
>>>> This is an update to an advisory notice issued to users of EGI’s GES
>>>> 300 and 400 series amplifiers on the delay of EEG data inherent in the
>>>> anti-alias filters of these amplifiers.
>>>>
>>>> In the original advisory notice, it was noted that the digital Finite
>>>> Impulse Response filters used after analog-to-digital conversion delay the
>>>> EEG by a fixed interval by the following values:
>>>>
>>>>
>>>> *Sampling Rate*
>>>>
>>>> *NA 300*
>>>>
>>>> *NA 400*
>>>>
>>>> *NA 405*
>>>>
>>>> *NA 410*
>>>>
>>>> 1000 s/s
>>>>
>>>>  8 ms (0.52)
>>>>
>>>>  36 ms (0.63)
>>>>
>>>>  36 ms (0.52)
>>>>
>>>>  13 ms (0.52)
>>>>
>>>> 500 s/s
>>>>
>>>>  18 ms (0.63)
>>>>
>>>>  66 ms (1.03)
>>>>
>>>>  66 ms (1.03)
>>>>
>>>>  34 ms (1.10)
>>>>
>>>> 250 s/s
>>>>
>>>>  36 ms (2.07)
>>>>
>>>>  112 ms (0)
>>>>
>>>>  112 ms (0)
>>>>
>>>>  76 ms (2.07)
>>>>
>>>> 125 s/s
>>>>
>>>>  72 ms (2.53)
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Without adjustment, the EEG is delayed with respect to real time and to
>>>> event markers that are aligned with real time. This delay does not affect
>>>> timing of events manually entered by the user with respect to the EEG
>>>> during acquisition.
>>>>
>>>> The delay values in the original Advisory Notice were verified with the
>>>> most recent versions of Net Station 4.5 and 5.0, representing the software
>>>> versions that are most widely used by our customer base. The original
>>>> Advisory Notice was issued immediately after this verification effort.
>>>>
>>>> Since releasing the original Advisory Notice on 28 August 2014, we have
>>>> continued our verification testing to confirm these delay values in all
>>>> other versions of Net Station associated with the NA 300 amplifier, in
>>>> order to provide our customers not using Net Station 4.5 or 5.0 with more
>>>> specific guidance.
>>>>
>>>> With the NA 300 amplifier, we found that the filter delay is only
>>>> present in Net Station version 4.4 and later; events are correctly aligned
>>>> with the EEG data when acquired with earlier versions of Net Station (4.3.1
>>>> and earlier). Furthermore, we found that for data recorded with Net Station
>>>> versions 4.4 through 4.5.7, the correction values for the default 250 s/s
>>>> sampling rate (which is likely used by the majority of customers) is 8 ms.
>>>>
>>>> For data acquired with the NA 400, NA 405 and NA 410 amplifiers, there
>>>> is no modification to the delay values presented in the original Advisory
>>>> Notice.
>>>>
>>>> Starting with Net Station 4.4, all data files contain an amplifier
>>>> serial number. This information can be used to determine whether
>>>> adjustments are required for a given data file acquired with an NA 300
>>>> amplifier. Contact EGI support for information on how to locate the
>>>> amplifier serial number (if present) in the data file.
>>>>
>>>> EGI will release a tool to adjust the latency delay in affected files
>>>> in the coming weeks. In addition, the Net Station software (version 5.1.2)
>>>> will provide an option for automatic alignment during acquisition.
>>>>
>>>>
>>>> <http://cts.vresp.com/c/?ElectricalGeodesicsI/becac2c8a8/2eeb100ff4/ec13d0112a/utm_content=ascherme%40uvm.edu&utm_source=VerticalResponse&utm_medium=Email&utm_term=&utm_campaign=Update%20to%20Advisory%20Notice%20-%20Anti-Alias%20Filter%20Effects%20on%20EEG%20Timing>Please
>>>> contact EGI support <supportteam at egi.com> for any questions.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *From:* eeglablist-bounces at sccn.ucsd.edu [mailto:
>>>> eeglablist-bounces at sccn.ucsd.edu] *On Behalf Of *Makoto Miyakoshi
>>>> *Sent:* Saturday, October 10, 2015 5:53 PM
>>>> *To:* Isaiah Innis <isainnis at indiana.edu>
>>>> *Cc:* EEGLAB List <eeglablist at sccn.ucsd.edu>
>>>> *Subject:* Re: [Eeglablist] Correct for EGI latency error functions
>>>>
>>>>
>>>>
>>>> Dear Isaiah,
>>>>
>>>>
>>>>
>>>> Thank you for sharing this info. I heard of it from Elise, one of
>>>> visitors here. EGI users, please pay attention!
>>>>
>>>>
>>>>
>>>> Makoto
>>>>
>>>>
>>>>
>>>> On Fri, Oct 9, 2015 at 9:48 AM, Isaiah Innis <isainnis at umail.iu.edu>
>>>> wrote:
>>>>
>>>> Hello eeglab list:
>>>>
>>>>
>>>>
>>>> Those of us who use EGI hydro-cel systems received "Advisory Notice:
>>>> Anti-Alias Filter Effects on EEG Timing" warning that there is a fixed
>>>> latency delay present for any event codes sent to the EEG during recording.
>>>> The EEG is delayed with respect to the events, and needs to be corrected by
>>>> either shifting the EEG forward or the events back. While it is
>>>> possible to correct this within NetStation, since our lab analyzes data
>>>> exclusively using eeglab I wrote a series of functions to correct the delay
>>>> within eeglab. It is my hope that others may find this beneficial. However,
>>>> I am a matlab novice and would like to see if anyone on the list has any
>>>> comments or suggestions.
>>>>
>>>>
>>>>
>>>> You can download a .zip archive with the functions here: <
>>>> https://www.dropbox.com/sh/2udz5qrdb79b2b8/AAAS6Bws_O65gJnpnATS1azza?dl=0
>>>> >.
>>>>
>>>>
>>>>
>>>> If you have any questions or criticisms upon reviewing the functions,
>>>> please contact me at: isainnis at indiana.edu
>>>>
>>>> If there is interest, I will make this a plugin for ease of use.
>>>>
>>>>
>>>>
>>>> Thank you,
>>>>
>>>> --
>>>>
>>>> Isaiah Innis
>>>> Indiana University '13
>>>> EEG Technician, IUB IRF
>>>>
>>>>
>>>> _______________________________________________
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>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> Makoto Miyakoshi
>>>> Swartz Center for Computational Neuroscience
>>>> Institute for Neural Computation, University of California San Diego
>>>>
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>>>
>>>
>>>
>>> --
>>> Makoto Miyakoshi
>>> Swartz Center for Computational Neuroscience
>>> Institute for Neural Computation, University of California San Diego
>>>
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>>
>>
>>
>> --
>> Isaiah Innis
>> Indiana University '13
>> EEG Technician, IUB IRF
>>
>>
>> _______________________________________________
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>
>
>
> --
> Ghislaine Dehaene-Lambertz
>
> #########################################
> Unité INSERM 992 "Neuroimagerie Cognitive"
> CEA/SAC/DSV/DRM/NeuroSpin
> Bat 145, point courrier 156
> 91191 GIF/YVETTE, France
> Telephone: +33 1 69 08 81 72   Fax: +33 1 69 08 79 73
> Couriel: ghislaineDOTdehaeneAROBASEcea.fr
> Web: www.unicog.org
> et le site de notre labo enfant (Kid's lab) !!!
> http://www.unicog.org/bblab/topic/index.html
> ##################################################"
>



-- 
Isaiah Innis
Indiana University '13
EEG Technician, IUB IRF
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