Assessing the accuracy of topographic EEG mapping for determining local brain function

Cook, Ian A.; O’Hara, Ruth; Uijtdehaage, Sebastian; Mandelkern, Mark; Leuchter, Andrew F.

doi:10.1016/s0013-4694(98)00092-3

Cited by 277 publications

(199 citation statements)

References 25 publications

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“…ization and integration of absolute and relative power values from all electrode sites for a given EEG recording; cordance values are calculated in three steps. First, EEG power values are computed using a re-attributional electrode montage in which power values from pairs of electrodes that share a common electrode are averaged together to yield the re-attributed power (Figure 2) (Cook et al 1998b). For example, to determine a power value for the brain region underlying the F4 electrode, one first computes power spectra for the channels that include the F4 electrode (i.e., F4-F8, F4-AF2, F4-FC2, and F4-FC6, in Figure 2), and then averages the absolute power values from those channels to obtain the reattributed power for the F4 electrode.…”

Section: Cordance Calculationsmentioning

confidence: 99%

“…This is somewhat similar to the single source method of Hjorth (1970Hjorth ( , 1975, but cordance recombines the power values whereas Hjorth's method recombines voltage signals by averaging signal amplitudes from pairs of electrodes. The Hjorth method is preferred under many experimental designs, particular when the source of a signal is the question of interest (e.g., seizure focus); the re-attributional montage provides a higher association between QEEG measures and regional cortical perfusion than does the Hjorth method (Cook et al 1998b) and so offers an advantage for testing our specific hypotheses. Relative power is calculated in the conventional manner, as the percentage of power in each band, relative to the total spectrum considered (here, 0.5 Hz to 20 Hz) (cf.…”

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confidence: 99%

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Early Changes in Prefrontal Activity Characterize Clinical Responders to Antidepressants

Cook¹,

Leuchter

Morgan

et al. 2002

Neuropsychopharmacology

182

169

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Previous studies have shown that changes in brain functionClinicians long have observed a lag time of several weeks between the initiation of antidepressant treatment and clinical response for many patients (Hyman and Nestler 1996;Katz et al. 1996). Some individuals do have early symptomatic improvement, and this has been reported to predict further improvement over the next several weeks (Nierenberg et al. 1995). Reports have suggested that some physiologic changes are seen shortly after initiation of treatment (Sulser 1989;Beck 1995;Dahmen et al. 1997). No clinically practical physiologic predictor of treatment response has yet been identified with these techniques, however, and the relationship of early physiologic changes to eventual clinical outcome remains incompletely understood.Quantitative electroencephalography (QEEG) has been used as a physiologic measure in efforts to address these questions. Prior work with "pharmaco-EEG" techniques has shown that the administration of antidepressant compounds yields reproducible changes in EEG activity in healthy control subjects within a few hours of dosing (Saletu et al. 1982(Saletu et al. , 1983(Saletu et al. , 1986(Saletu et al. , 1987(Saletu et al. , 1987 Grunberger 1985, 1988;Sannita et al. 1983;Sannita 1990; Early Prefrontal Changes in Depression 121Itil et al. 1984;Herrmann et al. 1991;Luthringer et al. 1996). The relationship of these immediate EEG changes in control subjects to eventual clinical response in a depressed population is unclear. Other QEEG work with depressed subjects has found that changes from baseline in theta power early in the course of treatment may characterize groups of depressed patients who are more likely to respond to antidepressant treatment (Ulrich et al. 1994). Unfortunately, the overlap in the value of these changes between responder and nonresponder groups precluded the use of this measure in response prediction for individual subjects, and prior research did not indicate how to relate changes in theta power to other measures of regional brain activity (e.g., regional cerebral blood flow or metabolism). We previously have shown that absolute and relative power are complementary measures of brain activity (Leuchter et al. 1993). A relatively new QEEG measure, "cordance," combines information from both absolute and relative power measures (Leuchter et al. 1994a(Leuchter et al. , 1994b. The algorithm yields two indicators: a categorical value ("concordant" or "discordant" state) and a numerical value for each electrode. In an earlier report with the categorical measure , we observed that depressed subjects exhibiting the concordant state prior to treatment had better treatment outcomes when treated with fluoxetine than did subjects with the discordant state. In this report, we use the num*erical values of cordance, because they allow examination of changes in regional brain activity with treatment. In validation against data collected simultaneously with [H 2 15O]-positron emission tomography (PET), cordance values in the the...

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Section: Cordance Calculationsmentioning

confidence: 99%

mentioning

confidence: 99%

Early Changes in Prefrontal Activity Characterize Clinical Responders to Antidepressants

Cook¹,

Leuchter

Morgan

et al. 2002

Neuropsychopharmacology

182

169

View full text Add to dashboard Cite

show abstract

“…Brain electrical activity can be measured using cordance, low-resolution brain electromagnetic tomography (LORETA), and antidepressant treatment (ATR) index. Cordance, which uses QEEG measurements conducted from a full scalp electrode array, assesses perfusion of cerebral cortex and brain activity on cortical convexities like PFC (Cook et al, 1998;Leuchter et al, 1999). Several groups have demonstrated the usefulness of cordance in characterizing antidepressant response (Bares et al, 2008;Cook et al, 2002).…”

Section: Neurostructural and Neurofunctional Studiesmentioning

confidence: 99%

Biological Alterations in Depression

Benton¹,

Wiltshire²

2011

Psychiatric Disorders - Trends and Developments

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“…EEG recordings were performed using the QND system (Neurodata, Inc., Pasadena, CA) while subjects rested in the eyes-closed, maximally alert state in a sound-attenuated room with subdued lighting, using procedures previously described in detail (Cook et al, 1998bLeuchter et al, 1992). Electrodes were placed with an electrode cap (ElectroCap; Eaton, OH) using an extended International 10-20 System with 35 recording electrodes ( Figure 1; Cook et al, 1998b).…”

Section: Qeeg Techniquesmentioning

confidence: 99%

“…Electrodes were placed with an electrode cap (ElectroCap; Eaton, OH) using an extended International 10-20 System with 35 recording electrodes ( Figure 1; Cook et al, 1998b). Eye movements were monitored with right infraorbital and left outer canthus electrodes.…”

Section: Qeeg Techniquesmentioning

confidence: 99%

Neurophysiologic Correlates of Side Effects in Normal Subjects Randomized to Venlafaxine or Placebo

Hunter

Leuchter

Morgan

et al. 2004

Neuropsychopharmacol

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Adverse events reported in the context of medication administration may be due to pharmacodynamic and/or nonpharmacodynamic effects (eg, nocebo phenomena). Neurophysiological substrates of side effects may be examined in placebo-controlled antidepressant treatment trials. We explored the relationship between side effects and regional neurophysiologic changes in normal subjects receiving a 1-week placebo lead-in followed by 4 weeks randomized treatment with placebo (n ¼ 15) or venlafaxine IR (n ¼ 17). Quantitative electroencephalographic (QEEG) cordance measures were obtained before and during treatment, and side effects were assessed weekly using semistructured interviews. Side effect burden, characterized as the mean number of side effects per postrandomization visit, correlated significantly with neurophysiologic changes in the antidepressant group but not the placebo group. Medication group side effects were negatively correlated with changes in prefrontal cordance at end of placebo lead-in (r ¼ À0.67, po0.003), at 2 weeks (r ¼ À0.77, po0.002), and at 4 weeks (r ¼ À0.77, po0.004) post randomization. After controlling for the prefrontal change at the end of placebo lead-in, postrandomization brain changes did not further explain side effect burden. Changes in prefrontal brain function associated with later antidepressant side effects were observed during placebo lead-inFprior to the administration of medication. Prefrontal brain function during brief placebo administration may help explain susceptibility to the development of antidepressant side effects. Results of these exploratory hypothesis-generating analyses should be considered tentative until replicated.

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Assessing the accuracy of topographic EEG mapping for determining local brain function

Cited by 277 publications

References 25 publications

Early Changes in Prefrontal Activity Characterize Clinical Responders to Antidepressants

Early Changes in Prefrontal Activity Characterize Clinical Responders to Antidepressants

Biological Alterations in Depression

Neurophysiologic Correlates of Side Effects in Normal Subjects Randomized to Venlafaxine or Placebo

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