Emma Whitham - Academia.edu (original) (raw)

Papers by Emma Whitham

Research paper thumbnail of Thinking activates EMG in scalp electrical recordings

Clinical Neurophysiology, 2008

Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings ... more Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings are predominantly due to electromyographic (EMG) activity. We hypothesized that increased EMG activity would be augmented by mental tasks in proportion to task difficulty and the requirement of these tasks for motor or visuo-motor output. EEG was recorded in 98 subjects whilst performing cognitive tasks and analysed to generate power spectra. In four other subjects, neuromuscular blockade was achieved pharmacologically providing EMG-free spectra of EEG at rest and during mental tasks. In comparison to the paralysed condition, power of scalp electrical recordings in the gamma range varied in distribution, being maximal adjacent to cranial or cervical musculature. There were non-significant changes in mean gamma range activity due to mental tasks in paralysed subjects. In normal subjects, increases in scalp electrical activity were observed during tasks, without relationship to task difficulty, but with tasks involving limb- or eye-movement having higher power. Electrical rhythms in the gamma frequency range recorded from the scalp are inducible by mental activity and are largely due to EMG un-related to cognitive effort. EMG varies with requirements for somatic or ocular movement more than task difficulty. Severe restrictions exist on utilizing scalp recordings for high frequency EEG.

Research paper thumbnail of The Symbol of Modern Medicine

Annals of Internal Medicine, 2004

Research paper thumbnail of Epilepsy

Prescribing for Elderly Patients, 2009

Research paper thumbnail of 312: Mental tasks reproducibly induce gamma frequency EEG rhythms in normals

Journal of Clinical Neuroscience, 2007

Research paper thumbnail of 020 Real-time capture of patient-reported outcomes using a digital platform – a pilot study

Oral abstracts, 2021

Objectives To demonstrate proof of concept/feasibility of a novel digital platform using real-tim... more Objectives To demonstrate proof of concept/feasibility of a novel digital platform using real-time capture of patient-reported outcomes for real-world research involving patients with epilepsy. Methods The phone app collects multi-faceted patient-reported outcomes including seizure frequency, medication side effects, mood, anxiety, quality of life and cognition along with voice and digital images. Patients are invited through a national consortium of 18 adult epilepsy centres in Australia. The patient-reported information potentially allows feedback to their treating specialists and tertiary centre in near real-time, along with deidentified aggregation across all participating centres for comparison. Currently, more than 40 patients are enrolled. We present the outcomes of one patient, with the longest-running data points. The new platform was developed by KeyLead Health TM, Melbourne Australia. Results The results report a single patient’s composite scores for mood, sleep, cognitio...

Research paper thumbnail of Efficacy and tolerability of adjuvant perampanel: an Australian multicenter real-world observational study in refractory focal and generalized epilepsy syndromes

Research paper thumbnail of 2003, ‘The Symbol of Modern Medicine: Why One Snake Is More Than Two

Today, two serpent motifs are commonly used to symbolize the practice and profession of medicine.... more Today, two serpent motifs are commonly used to symbolize the practice and profession of medicine. Internationally, the most pop-ular symbol of medicine is the single serpent–entwined staff of Asklepios (Latin, Aesculapius), the ancient Greco-Roman god of medicine. However, in the United States, the staff of Asklepios (the Asklepian) and a double serpent–entwined staff with sur-mounting wings (the caduceus) are both popular medical symbols. The latter symbol is often designated as the “medical caduceus” and is equated with the ancient caduceus, the double serpent– entwined staff of the Greco-Roman god Hermes (Latin, Mercury). Many physicians would be surprised to learn that the medical caduceus has a quite modern origin: Its design is derived not from the ancient caduceus of Hermes but from the printer’s mark of a popular 19th-century medical publisher. Furthermore, this modern caduceus became a popular medical symbol only after its adoption by the U.S. Army Medical Corps at the begi...

Research paper thumbnail of Epilepsy and Seizure-Related Hospital Admissions to an Australian Neurology Unit: A Prospective Observational Study

Research paper thumbnail of Potential role of cannabidiol for seizure control in a patient with recurrent glioma

Journal of Clinical Neuroscience

Research paper thumbnail of Fast and effective removal of contamination from scalp electrical recordings

Research paper thumbnail of Resting cranial and upper cervical muscle activity is increased in patients with migraine

Research paper thumbnail of Improved artefact removal from EEG using Canonical Correlation Analysis and spectral slope

Journal of neuroscience methods, Jan 15, 2018

Contamination of scalp measurement by tonic muscle artefacts, even in resting positions, is an un... more Contamination of scalp measurement by tonic muscle artefacts, even in resting positions, is an unavoidable issue in EEG recording. These artefacts add significant energy to the recorded signals, particularly at high frequencies. To enable reliable interpretation of subcortical brain activity, it is necessary to detect and discard this contamination. We introduce a new automatic muscle-removal approach based on the traditional Blind Source Separation-Canonical Correlation Analysis (BSS-CCA) method and the spectral slope of its components. We show that CCA-based muscle-removal methods can discriminate between signals with high correlation coefficients (brain, mains artefact) and signals with low correlation coefficients (white noise, muscle). We also show that typical BSS-CCA components are not purely from one source, but are mixtures from multiple sources, limiting the performance of BSS-CCA in artefact removal. We demonstrate, using our paralysis dataset, improved performance using ...

Research paper thumbnail of Evaluation of a minimum-norm based beamforming technique, sLORETA, for reducing tonic muscle contamination of EEG at sensor level

Journal of Neuroscience Methods

Research paper thumbnail of EpiNet as a way of involving more physicians and patients in epilepsy research: Validation study and accreditation process

Research paper thumbnail of Thinking activates EMG in scalp electrical recordings

Clinical …, 2008

Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings ... more Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings are predominantly due to electromyographic (EMG) activity. We hypothesized that increased EMG activity would be augmented by mental tasks in proportion to task difficulty and the requirement of these tasks for motor or visuo-motor output. EEG was recorded in 98 subjects whilst performing cognitive tasks and analysed to generate power spectra. In four other subjects, neuromuscular blockade was achieved pharmacologically providing EMG-free spectra of EEG at rest and during mental tasks. In comparison to the paralysed condition, power of scalp electrical recordings in the gamma range varied in distribution, being maximal adjacent to cranial or cervical musculature. There were non-significant changes in mean gamma range activity due to mental tasks in paralysed subjects. In normal subjects, increases in scalp electrical activity were observed during tasks, without relationship to task difficulty, but with tasks involving limb- or eye-movement having higher power. Electrical rhythms in the gamma frequency range recorded from the scalp are inducible by mental activity and are largely due to EMG un-related to cognitive effort. EMG varies with requirements for somatic or ocular movement more than task difficulty. Severe restrictions exist on utilizing scalp recordings for high frequency EEG.

Research paper thumbnail of Epilepsy

Prescribing for Elderly Patients, 2009

Research paper thumbnail of Reduction of medical error at the point-of-care using electronic clinical information delivery

Internal Medicine Journal, 2003

There is accumulating evidence that point-of-care delivery of clinical information such as eviden... more There is accumulating evidence that point-of-care delivery of clinical information such as evidence-based medicine, practice guidelines and drug information can streamline clinical practice and reduce preventable errors. In Australia, hospital-based physicians have -generally been slow to fully use these resources to enhance their clinical practice. Here we provide an introduction to the practical application of several hand-held and electronic information systems available to Australian physicians.

Research paper thumbnail of Relation of Gamma Oscillations in Scalp Recordings to Muscular Activity

Brain Topography, 2009

We recorded scalp electrical activity before and after full neuro-muscular paralysis in 5 volunte... more We recorded scalp electrical activity before and after full neuro-muscular paralysis in 5 volunteers and determined differences due to elimination of muscular activity on several standard applications of EEG. Due to paralysis, there were reductions in 'noisiness' of the standard scalp recordings which were maximal over the peripheral scalp, not explained by abolition of movement artefact, and best accounted for by sustained EMG activity in resting individuals. There was a corresponding reduction in spectral power in the gamma range. In central leads, the extent of gamma frequency coherence during a non-time-locked mental task (1 s epochs) was reduced by paralysis, likely due to a reduction in gamma-frequency coherence in widely arising EMG signals. In a time-locked mental task (auditory oddball), evoked responses were qualitatively unaffected by paralysis but 3 of 4 induced gamma responses were obscured by EMG.

Research paper thumbnail of Scalp electrical recording during paralysis: Quantitative evidence that EEG frequencies above 20Hz are contaminated by EMG

Clinical Neurophysiology, 2007

Research paper thumbnail of Effects of potassium channel blockade on endogenous glutamate release from cerebellar slices

Brain Research, 1989

The effects of potassium channel blockade on the spontaneous release of endogenous glutamate from... more The effects of potassium channel blockade on the spontaneous release of endogenous glutamate from rat cerebellar slices was studied. Tetrapentylammonium (TPeA), 4-aminopyridine and quinine all increased the spontaneous release of glutamate. The effect of TPeA and 4-AP was potentiated in the absence of Ca2+ from the perfusing fluid. In normal artificial cerebrospinal fluid (ACSF) the Ca2+ channel antagonist, verapamil, mimicked the effects of TPeA seen in Ca2+-free ACSF. The increased release of glutamate produced by TPeA under Ca2+-free conditions was inhibited by the sodium channel blocker, tetrodotoxin, and by Ruthenium red, which inhibits mobilization of mitochondrial Ca2+. The results suggest that external Ca2+ is not required in the TPeA-induced release of glutamate. It is proposed that the prolongation of depolarization seen with potassium channel blocking drugs enables sufficient sodium to enter the neurone and release Ca2+ from intraneuronal stores in order to facilitate transmitter release.

Research paper thumbnail of Thinking activates EMG in scalp electrical recordings

Clinical Neurophysiology, 2008

Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings ... more Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings are predominantly due to electromyographic (EMG) activity. We hypothesized that increased EMG activity would be augmented by mental tasks in proportion to task difficulty and the requirement of these tasks for motor or visuo-motor output. EEG was recorded in 98 subjects whilst performing cognitive tasks and analysed to generate power spectra. In four other subjects, neuromuscular blockade was achieved pharmacologically providing EMG-free spectra of EEG at rest and during mental tasks. In comparison to the paralysed condition, power of scalp electrical recordings in the gamma range varied in distribution, being maximal adjacent to cranial or cervical musculature. There were non-significant changes in mean gamma range activity due to mental tasks in paralysed subjects. In normal subjects, increases in scalp electrical activity were observed during tasks, without relationship to task difficulty, but with tasks involving limb- or eye-movement having higher power. Electrical rhythms in the gamma frequency range recorded from the scalp are inducible by mental activity and are largely due to EMG un-related to cognitive effort. EMG varies with requirements for somatic or ocular movement more than task difficulty. Severe restrictions exist on utilizing scalp recordings for high frequency EEG.

Research paper thumbnail of The Symbol of Modern Medicine

Annals of Internal Medicine, 2004

Research paper thumbnail of Epilepsy

Prescribing for Elderly Patients, 2009

Research paper thumbnail of 312: Mental tasks reproducibly induce gamma frequency EEG rhythms in normals

Journal of Clinical Neuroscience, 2007

Research paper thumbnail of 020 Real-time capture of patient-reported outcomes using a digital platform – a pilot study

Oral abstracts, 2021

Objectives To demonstrate proof of concept/feasibility of a novel digital platform using real-tim... more Objectives To demonstrate proof of concept/feasibility of a novel digital platform using real-time capture of patient-reported outcomes for real-world research involving patients with epilepsy. Methods The phone app collects multi-faceted patient-reported outcomes including seizure frequency, medication side effects, mood, anxiety, quality of life and cognition along with voice and digital images. Patients are invited through a national consortium of 18 adult epilepsy centres in Australia. The patient-reported information potentially allows feedback to their treating specialists and tertiary centre in near real-time, along with deidentified aggregation across all participating centres for comparison. Currently, more than 40 patients are enrolled. We present the outcomes of one patient, with the longest-running data points. The new platform was developed by KeyLead Health TM, Melbourne Australia. Results The results report a single patient’s composite scores for mood, sleep, cognitio...

Research paper thumbnail of Efficacy and tolerability of adjuvant perampanel: an Australian multicenter real-world observational study in refractory focal and generalized epilepsy syndromes

Research paper thumbnail of 2003, ‘The Symbol of Modern Medicine: Why One Snake Is More Than Two

Today, two serpent motifs are commonly used to symbolize the practice and profession of medicine.... more Today, two serpent motifs are commonly used to symbolize the practice and profession of medicine. Internationally, the most pop-ular symbol of medicine is the single serpent–entwined staff of Asklepios (Latin, Aesculapius), the ancient Greco-Roman god of medicine. However, in the United States, the staff of Asklepios (the Asklepian) and a double serpent–entwined staff with sur-mounting wings (the caduceus) are both popular medical symbols. The latter symbol is often designated as the “medical caduceus” and is equated with the ancient caduceus, the double serpent– entwined staff of the Greco-Roman god Hermes (Latin, Mercury). Many physicians would be surprised to learn that the medical caduceus has a quite modern origin: Its design is derived not from the ancient caduceus of Hermes but from the printer’s mark of a popular 19th-century medical publisher. Furthermore, this modern caduceus became a popular medical symbol only after its adoption by the U.S. Army Medical Corps at the begi...

Research paper thumbnail of Epilepsy and Seizure-Related Hospital Admissions to an Australian Neurology Unit: A Prospective Observational Study

Research paper thumbnail of Potential role of cannabidiol for seizure control in a patient with recurrent glioma

Journal of Clinical Neuroscience

Research paper thumbnail of Fast and effective removal of contamination from scalp electrical recordings

Research paper thumbnail of Resting cranial and upper cervical muscle activity is increased in patients with migraine

Research paper thumbnail of Improved artefact removal from EEG using Canonical Correlation Analysis and spectral slope

Journal of neuroscience methods, Jan 15, 2018

Contamination of scalp measurement by tonic muscle artefacts, even in resting positions, is an un... more Contamination of scalp measurement by tonic muscle artefacts, even in resting positions, is an unavoidable issue in EEG recording. These artefacts add significant energy to the recorded signals, particularly at high frequencies. To enable reliable interpretation of subcortical brain activity, it is necessary to detect and discard this contamination. We introduce a new automatic muscle-removal approach based on the traditional Blind Source Separation-Canonical Correlation Analysis (BSS-CCA) method and the spectral slope of its components. We show that CCA-based muscle-removal methods can discriminate between signals with high correlation coefficients (brain, mains artefact) and signals with low correlation coefficients (white noise, muscle). We also show that typical BSS-CCA components are not purely from one source, but are mixtures from multiple sources, limiting the performance of BSS-CCA in artefact removal. We demonstrate, using our paralysis dataset, improved performance using ...

Research paper thumbnail of Evaluation of a minimum-norm based beamforming technique, sLORETA, for reducing tonic muscle contamination of EEG at sensor level

Journal of Neuroscience Methods

Research paper thumbnail of EpiNet as a way of involving more physicians and patients in epilepsy research: Validation study and accreditation process

Research paper thumbnail of Thinking activates EMG in scalp electrical recordings

Clinical …, 2008

Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings ... more Fast electrical rhythms in the gamma range (30-100Hz) in scalp (but not intracranial) recordings are predominantly due to electromyographic (EMG) activity. We hypothesized that increased EMG activity would be augmented by mental tasks in proportion to task difficulty and the requirement of these tasks for motor or visuo-motor output. EEG was recorded in 98 subjects whilst performing cognitive tasks and analysed to generate power spectra. In four other subjects, neuromuscular blockade was achieved pharmacologically providing EMG-free spectra of EEG at rest and during mental tasks. In comparison to the paralysed condition, power of scalp electrical recordings in the gamma range varied in distribution, being maximal adjacent to cranial or cervical musculature. There were non-significant changes in mean gamma range activity due to mental tasks in paralysed subjects. In normal subjects, increases in scalp electrical activity were observed during tasks, without relationship to task difficulty, but with tasks involving limb- or eye-movement having higher power. Electrical rhythms in the gamma frequency range recorded from the scalp are inducible by mental activity and are largely due to EMG un-related to cognitive effort. EMG varies with requirements for somatic or ocular movement more than task difficulty. Severe restrictions exist on utilizing scalp recordings for high frequency EEG.

Research paper thumbnail of Epilepsy

Prescribing for Elderly Patients, 2009

Research paper thumbnail of Reduction of medical error at the point-of-care using electronic clinical information delivery

Internal Medicine Journal, 2003

There is accumulating evidence that point-of-care delivery of clinical information such as eviden... more There is accumulating evidence that point-of-care delivery of clinical information such as evidence-based medicine, practice guidelines and drug information can streamline clinical practice and reduce preventable errors. In Australia, hospital-based physicians have -generally been slow to fully use these resources to enhance their clinical practice. Here we provide an introduction to the practical application of several hand-held and electronic information systems available to Australian physicians.

Research paper thumbnail of Relation of Gamma Oscillations in Scalp Recordings to Muscular Activity

Brain Topography, 2009

We recorded scalp electrical activity before and after full neuro-muscular paralysis in 5 volunte... more We recorded scalp electrical activity before and after full neuro-muscular paralysis in 5 volunteers and determined differences due to elimination of muscular activity on several standard applications of EEG. Due to paralysis, there were reductions in 'noisiness' of the standard scalp recordings which were maximal over the peripheral scalp, not explained by abolition of movement artefact, and best accounted for by sustained EMG activity in resting individuals. There was a corresponding reduction in spectral power in the gamma range. In central leads, the extent of gamma frequency coherence during a non-time-locked mental task (1 s epochs) was reduced by paralysis, likely due to a reduction in gamma-frequency coherence in widely arising EMG signals. In a time-locked mental task (auditory oddball), evoked responses were qualitatively unaffected by paralysis but 3 of 4 induced gamma responses were obscured by EMG.

Research paper thumbnail of Scalp electrical recording during paralysis: Quantitative evidence that EEG frequencies above 20Hz are contaminated by EMG

Clinical Neurophysiology, 2007

Research paper thumbnail of Effects of potassium channel blockade on endogenous glutamate release from cerebellar slices

Brain Research, 1989

The effects of potassium channel blockade on the spontaneous release of endogenous glutamate from... more The effects of potassium channel blockade on the spontaneous release of endogenous glutamate from rat cerebellar slices was studied. Tetrapentylammonium (TPeA), 4-aminopyridine and quinine all increased the spontaneous release of glutamate. The effect of TPeA and 4-AP was potentiated in the absence of Ca2+ from the perfusing fluid. In normal artificial cerebrospinal fluid (ACSF) the Ca2+ channel antagonist, verapamil, mimicked the effects of TPeA seen in Ca2+-free ACSF. The increased release of glutamate produced by TPeA under Ca2+-free conditions was inhibited by the sodium channel blocker, tetrodotoxin, and by Ruthenium red, which inhibits mobilization of mitochondrial Ca2+. The results suggest that external Ca2+ is not required in the TPeA-induced release of glutamate. It is proposed that the prolongation of depolarization seen with potassium channel blocking drugs enables sufficient sodium to enter the neurone and release Ca2+ from intraneuronal stores in order to facilitate transmitter release.