[wineeg] Re: theta question

  • From: "Juri D. Kropotov" <kropotov@xxxxxxxxxx>
  • To: "Vernon, David" <d.vernon@xxxxxxxxxxxxxx>
  • Date: Wed, 23 Jul 2003 15:15:33 +0400

I understand your concern, David.

It's true that some ADHD children may have slow alpha which can be
mixed with theta at Cz.

However the effect of occipital or parietal alpha at Cz could be
diminished by simply considering Eyes opened condition.  Opening eyes
dramatically suppresses this type of alpha.  CMR rhythm is usually
higher that 8 Hz and can not contaminate Cz reading.

VD> Hello,

VD> can anybody help clarify an issue for me. 

VD> I have examined the eeg of a number of children with ADHD and quite a few
VD> show a high (ie greater than 4) theta/beta ratio at CZ. This is when theta
VD> is defined as 4-8hz and beta as 13-21hz, as per Monastra's procedure etc.

VD> However, when i look at the theta at CZ what i 'think' i'm seeing is really
VD> slow alpha. That is, its peaking around 7.2-7.5Hz, it attenuates when eyes
VD> are open relative to closed, and there is only the one peak. Its not like
VD> this is a theta peak and there is also an alpha peak. My concern is that
VD> strictly speaking, if one were to adhere to the numbers, this patient
VD> exhibits an extremely high theta/beta ratio and as such could benefit from
VD> neurofeedback aimed at reducing theta and enhancing beta. However, i think
VD> that what is really the case is that the patient shows a slightly slow alpha
VD> peak, which could be a result of the age of the child, and may just speed up
VD> with age. In addition, if one takes Klimesch's view and identifies the
VD> 'individual alpha frequency' +/- 2hz this peak would without doubt be within
VD> the individual alpha range. As such the only neurofeedback that would seem
VD> appropriate would be to focus on speeding up alpha.

VD> I suppose my question is really this: A wide range of literature suggests
VD> that some children with ADHD may exhibit an excess of theta and a deficit of
VD> beta making neurofeedback a therapeutic option, however is this true Theta
VD> or is it slow alpha? Either way what would you recommend? 

VD> As usual any comments etc would be gratefully received

VD> david

VD> David J Vernon PhD
VD> Dept. of Cognitive Neuroscience & Behaviour
VD> Imperial College London
VD> St Dunstan's Road
VD> London
VD> W6 8RP

VD> Tel:    44 (0) 208 383 0584
VD> Fax:   44 (0) 208 846 1670

VD> -----Original Message-----
VD> From: Joe Siri Ekgren [mailto:vennskap@xxxxxxxxx]
VD> Sent: 09 April 2003 19:16
VD> To: wineeg@xxxxxxxxxxxxx
VD> Subject: [wineeg] Latest version of WinEEG, solves time clock error

VD> Dear Listmembers,

VD> With the latest version of WinEEG, the software now records in real 
VD> time on laptops with Win98. (Previous versions ran at half speed, 
VD> i.e. a recording length of 60 WinEEG one second epochs took 160 
VD> seconds in real time under Win98). The screen gets more jumpy on my 
VD> 500 Mhz laptop, and harder to read, so there is a price for 
VD> everything.

VD> I can=B4t find an updated version number, but the new version is 
VD> exactly 1 699 480 bytes.

VD> Valery says that the improvements are:
>>1.  It works faster under Windows XP during EEG recording.
>>2. It is possible to use graphics acceleration (See "Equipment parameters"
>>menu Setup). To use graphics acceleration you need to install DirectX 7 or
>>3. It is possible to change parameters of COM port that is used for
>>synchronization of PSYTASK. (See "Equipment parameters" menu Setup).This
>>possibility can help in some cases when COM ports of computers work bad.

VD> There is no download site, but I will be happy to forward this WinEEG 
VD> version to anyone interested.

Best regards,
 Juri                            mailto:kropotov@xxxxxxxxxx

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