Reading Clinical EEG (.ezdata) file IN MATLAB

how can we read a clinical EEG that is in .ezdata file format in Matlab. Following is the data from one subject and it shows the Ezdata in the name.i have searched alot but i am unable to find any sort of converter for this format.i have also attached the file which i am trying to read in Matlab in compressed folder.how can we read this file in matlab or convert it to some format that is supported by MATLAB.THANKS.The machine used for recording this data is Cadwell Arc Essentia.

[Star Strider]

I cannot find any information online about that file extension. I cannot even find out what software creates them.

See if there are other export options in the software, ideally as MATLAB .mat files, although other formats MATLAB can import are also options.

[Hassan Nawazish]

actually i think its .e file and i saw your answer from three years ago ,you mentioned https://github.com/ieeg-portal/Nicolet-Reader , but the problem is that i am unable to understand that . we are getting this error

[Hassan Nawazish]

if possible kindly open the attached data file and apply this method yourself .it will be very efficent way to understand the problem for you.

[deying liu]

hello,have u solved the problem?I face the same problem

Answer 1

[Cris LaPierre]

ezdata appears to be a file created by Cadwell EEG Machines (along with .eas and .ez3). Based on what I see in the attached file, it is in SQLite format 3, which appears to be a database file. If you have access to the Database Toolbox, you can use sqlread to load the data.

zipFile = 'ace8295e-7820-...7-02-18-1.zip';
unzip(zipFile)

% Connect to the database
conn = sqlite('ace8295e-7820-4076-b08b-f533449786d1-2019-02-05-07-02-18-1.ezdata')

conn = 
  sqlite with properties:

      Database: 'ace8295e-7820-4076-b08b-f533449786d1-2019-02-05-07-02-18-1.ezdata'
    IsReadOnly: 0
    AutoCommit: 'on'

% List all database contents
data = sqlfind(conn,'')

data = 11×5 table
    Catalog    Schema             Table                                                                                            Columns                                                                                   Type
    _______    ______    ________________________    ____________________________________________________________________________________________________________________________________________________________________    ____

      ""         ""      "FrameInfo"                 {["DataKey"    "FrameKey"    "Data"                                                                                                                               ]}     "" 
      ""         ""      "MediaHeader"               {["Key"    "Value"                                                                                                                                                ]}     "" 
      ""         ""      "MediaHeaderSyncRowData"    {["Key"    "UpdateTick"    "UpdateTimeStamp"    "UpdateClientID"    "DeletedFlag"                                                                                 ]}     "" 
      ""         ""      "MiscInfo"                  {["TimeStamp"    "Key"    "Value"                                                                                                                                 ]}     "" 
      ""         ""      "MiscInfoSyncRowData"       {["TimeStamp"    "Key"    "UpdateTick"    "UpdateTimeStamp"    "UpdateClientID"    "DeletedFlag"                                                                  ]}     "" 
      ""         ""      "syncrowdata"               {["SyncTableKey"    "PrimaryKey"    "UpdateTick"    "UpdateTimeStamp"    "UpdateClientID"    "DeletedFlag"                                                        ]}     "" 
      ""         ""      "synctable"                 {["SyncTableKey"    "TableName"    "PrimaryKey"    "Direction"    "UploadAnchor"    "DownloadAnchor"    "UploadTimeStamp"    "DownloadTimeStamp"    "SyncRowTable"]}     "" 
      ""         ""      "sqlite_sequence"           {["name"    "seq"                                                                                                                                                 ]}     "" 
      ""         ""      "TrackInfo"                 {["Offset"    "Track"    "Data"                                                                                                                                   ]}     "" 
      ""         ""      "TrackInfoSyncRowData"      {["Offset"    "Track"    "UpdateTick"    "UpdateTimeStamp"    "UpdateClientID"    "DeletedFlag"                                                                   ]}     "" 
      ""         ""      "SchemaUpdateLog"           {["LogKey"    "OldVersion"    "NewVersion"    "TimeStamp"    "UpdateScript"                                                                                       ]}     "" 

It looks like FrameInfo contains the actual data, so load that using sqlread

% Load a table from the database (must know the name)
vals = sqlread(conn,data.Table(1))

vals = 338×3 table
      DataKey         FrameKey           Data      
    ____________    ____________    _______________

    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}
    {16×1 uint8}    {16×1 uint8}    {18564×1 uint8}

% plot first track
plot(vals.Data{1})

This should be enough to get your started.

Answer 2

[jan brogger]

I am the author of an FieldTrip/EEGLAB plugin that reads Nicolet EEG files. I now have the same problem of working with Cadwell Arc .ezdata files. I might work on an EEGLAB plugin for Cadwell Arc .ezdata files. I have been able to reproduce @Cris LaPierre parsing of an .ezdata file as a SQLite database. Cris is probably right that the EEG data are in the FrameInfo table.

On a test EEG file which is 1199 seconds long (19 minutes 59 seconds) about 20 channels at 500 Hz, the FrameInfo table contains 1199 rows. Try using this statement.

SELECT COUNT(Data) FROM 'FrameInfo'

returns 1199. This is suspiciously like the number of seconds in the file.

Each line contains 10449 comma-separated values. So the data matrix contains (1199x10449) = 12528351 values.

The expected size of the EEG data matrix for 20 channels at 500 Hz at 1199 seconds is 11 990 000 data points. So it is not far off to think that this is a matrix with a header of 538 351 points, and a data matrix of 11 990 000 data points.

The SyncInfo table contains sync items at about one second distance Try:

SELECT UpdateTimeStamp FROM 'syncrowdata'

Parsing the EEG file is somewhat limited by the fact that the information about the EEG channels, which is likely in the TrackInfo table, is a binary large object (blob). Try:

SELECT * FROM 'TrackInfo'

So the extraction of raw EEG data from Cadwell Arc .ezdata format seems possible, but needs more work.

Please reply to this post if conversion of Cadwell Arc is of interest.