Dr Kate Hoy - Researcher Profile

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Address

School of Psychology and Psychiatry
Building 17, Clayton

Biography

Understanding the key to mental illness

Stimulating the brain with electric currents is an effective way to treat some mental illnesses. How does it work? No one exactly knows. Dr Kate Hoy hopes that delving into that mystery will pave the way for the development of safe and effective techniques that will give new promise to patients whose problems fail to respond to traditional treatments.

“Everything we are is from the brain,” Kate says. Its complexity fascinates her, and so does its capacity to go wrong.

One of the early symptoms for people who develop schizophrenia is difficulty with what is known as working memory. 

This ability to hold in our minds all the information we need to carry out tasks is crucial for everything from writing a shopping list to holding down a job. 

Not only does a deficit in working memory show up as an early symptom of schizophrenia, it tends to linger even when standard treatments have dispelled more dramatic symptoms such as hallucinations and delusions. As such, it could hold the key to greater understanding. 

“If we can find out what causes the cognitive problems, maybe that will give us a clue as to what’s happening with the illness in general,” Kate says.

With support from the Monash Research Accelerator program, she is studying one type of treatment, transcranial direct current stimulation, or tDCS. It involves sending a weak electrical current into the brain. The patient remains awake, feeling little more than a tingle. 

Establishing that tDCS helps working memory is relatively straightforward, although to date the benefits are fleeting. Kate would like to extend the gains without raising the risks.  

And she would like to be able to answer that “why?” question. 

“Some of the research I’m doing now is trying to work out exactly why it helps.”

As well as improving cognition in people with schizophrenia, Kate is working on protecting it in those whose depression is not helped by standard treatments or counselling. 

“Electroconvulsive therapy, or ECT, is probably the most effective treatment for depression there is, but it’s got some problems with cognitive side-effects,” she says. Memory loss is common.

She coordinates research into the potential of magnetic seizure therapy (MST) as an alternative. Rather than using electric shocks to induce seizures, MST uses magnetic fields. Unlike ECT, it can be focused on specific parts of the brain. 

Promising results emerged in a recent pilot study funded by beyondblue. 

“We are finding no memory or cognitive side-effects,” Kate says. Direct comparisons between the treatments are now under way in a large-scale trial, supported by Kate’s National Health and Medical Research Council Fellowship and a project grant. 

While Kate hopes to establish new treatments, an overarching aim is greater understanding.

“Mental illnesses are such debilitating illnesses and there really is little known about many of them,” she says. “The more research we do into what the underlying problems are, the more likely we are to come up with a treatment that works. And the more we know about how these treatments work, the more we can optimise them to make sure they’re working as best they can.” 

Qualifications

DOCTORATE OF CLINICAL NEUROPSYCHOLOGY
Institution: Monash University
Year awarded: 2007
BACHELOR OF BEHAVIOURAL NEUROSCIENCE (HONS)
Institution: Monash University
Year awarded: 2003

Publications

Book Chapters

Fitzgerald, P.B., Hoy, K.E., 2012, Neuromodulation Techniques to Treat Hallucinations, in The Neuroscience of Hallucinations, eds Ed Renaud Jardi, Delphine Pins, Arnaud Cachia, Pierre Thomas, Springer Science+Business Media, New York NY USA, pp. 493-511.

Journal Articles

Hoy, K.E., Thomson, R.H.S., Cherk, M.H., Yap, K.S., Daskalakis, Z.J., Fitzgerald, P.B., 2013, Effect of magnetic seizure therapy on regional brain glucose metabolism in major depression, Psychiatry Research - Neuroimaging [P], vol 211, issue 2, Elsevier Ireland Ltd, Ireland, pp. 169-175.

Fitzgerald, P.B., Hoy, K.E., Herring, S.E., Clinton, A.M., Downey, G., Daskalakis, Z.J., 2013, Pilot study of the clinical and cognitive effects of high-frequency magnetic seizure therapy in major depressive disorder, Depression And Anxiety [P], vol 30, issue 2, John Wiley & Sons Inc., United States, pp. 129-136.

Fitzgerald, P.B., Hoy, K.E., Herring, S.E., McQueen, S.A., Peachey, A., Segrave, R.A., Maller, J.J., Hall, P.J., Daskalakis, Z.J., 2012, A double blind randomized trial of unilateral left and bilateral prefrontal cortex transcranial magnetic stimulation in treatment resistant major depression, Journal of Affective Disorders [P], vol 139, issue 2, Elsevier BV, Netherlands, pp. 193-198.

Blumberger, D.M., Tran, L.C., Fitzgerald, P.B., Hoy, K.E., Daskalakis, Z.J., 2012, A randomized double-blind sham-controlled study of transcranial direct current stimulation for treatment-resistant major depression, Frontiers in Psychiatry [E], vol 3, issue Art. No.: 74, Frontiers Research Foundation, Switzerland, pp. 1-8.

Fitzgerald, P.B., Grace, N.L., Hoy, K.E., Bailey, M.J., Daskalakis, Z.J., 2012, An open label trial of clustered maintenance rTMS for patients with refractory depression, Brain Stimulation [P], vol e-pub, Elsevier Inc., United States, pp. 1-6.

Furtado, C., Hoy, K.E., Maller, J.J., Savage, G., Daskalakis, Z.J., Fitzgerald, P.B., 2012, Cognitive and volumetric predictors of response to repetitive transcranial magnetic stimulation (rTMS) - a prospective follow-up study, Psychiatry Research - Neuroimaging [P], vol 202, issue 1, Elsevier Ireland Ltd, Ireland, pp. 12-19.

Hoy, K.E., Segrave, R.A., Daskalakis, Z.J., Fitzgerald, P.B., 2012, Investigating the relationship between cognitive change and antidepressant response following rTMS: a large scale retrospective study, Brain Stimulation [P], vol 5, issue 4, Elsevier Inc., United States, pp. 539-546.

Enticott, P.G., Arnold, S., Fitzgibbon, B., Hoy, K.E., Susilo, D., Fitzgerald, P.B., 2012, Transcranial direct current stimulation (tDCS) of the inferior frontal gyrus disrupts interpersonal motor resonance, Neuropsychologia [P], vol 50, issue 7, Pergamon, United Kingdom, pp. 1628-1631.

Andrews, S., Hoy, K.E., Enticott, P.G., Daskalakis, Z.J., Fitzgerald, P.B., 2011, Improving working memory: The effect of combining cognitive activity and anodal transcranial direct current stimulation to the left dorsolateral prefrontal cortex, Brain Stimulation [P], vol 4, issue 2, Elsevier Inc., United States, pp. 84-89.

Mulquiney, P.G., Hoy, K.E., Daskalakis, Z.J., Fitzgerald, P.B., 2011, Improving working memory: Exploring the effect of transcranial random noise stimulation and transcranial direct current stimulation on the dorsolateral prefrontal cortex, Clinical Neurophysiology [P], vol 122, issue 12, Elsevier Ireland Ltd, Shannon, Co. Clare Ireland, pp. 2384-2389.

Teo, F., Hoy, K., Daskalakis, Z., Fitzgerald, P., 2011, Investigating the role of current strength in tDCS modulatin of working memory performance in healthy controls, Frontiers in Psychiatry [E], vol 2, issue 45, Frontiers Research Foundation, Switzerland, pp. 1-6.

Hoy, K.E., Fitzgerald, P.B., 2011, Magnetic seizure therapy for treatment-resistant depression, Expert Review of Medical Devices [P], vol 8, issue 6, Expert Reviews Ltd, London, N3 1QB United Kingdom, pp. 723-732.

Fitzgerald, P., Hoy, K., Maller, J., Herring, S., Segrave, R., McQueen, S., Peachey, A., Hollander, Y., Anderson, J., Daskalakis, Z., 2011, Transcranial magnetic stimulation for depression after a traumatic brain injury, Journal Of Ect [P], vol 27, issue 1, Lippincott Williams & Wilkins, United States, pp. 38-40.

Fitzgerald, P.B., Hoy, K.E., Gunewardene, R., Slack, C., Ibrahim, S., Bailey, M., Daskalakis, Z., 2010, A randomized trial of unilateral and bilateral prefrontal cortex transcranial magnetic stimulation in treatment-resistant major depression, Psychological Medicine [P], vol 41, Cambridge University Press, United Kingdom, pp. 1187-1196.

Hoy, K.E., Fitzgerald, P.B., 2010, Brain stimulation in psychiatry and its effects on cognition, Nature Reviews Neurology [P], vol 6, issue 5, Nature Publishing Group, UK, pp. 267-275.

Hoy, K., Enticott, P., Daskalakis, Z., Fitzgerald, P., 2010, Can a behavioral intervention enhance the effect of repetitive transcranial magnetic stimulation on mood?, Brain Stimulation [P], vol 3.00, issue 4, Elsevier Inc., USA, pp. 200-206.

Hoy, K.E., Fitzgerald, P.B., 2010, Introducing magnetic seizure therapy: A novel therapy for treatment resistant depression, Australian And New Zealand Journal Of Psychiatry [P], vol 44, issue 7, Informa Healthcare, United Kingdom, Australia, pp. 591-598.

Hoy, K., Fitzgerald, P., 2010, Spreading activation: the origins of brain stimulation in psychiatry, Acta Neuropsychiatrica [P], vol 22, Wiley-Blackwell Publishing, USA, pp. 302-304.

Johnston, P., Enticott, P., Mayes, A., Hoy, K., Herring, S., Fitzgerald, P., 2010, Symptom correlates of static and dynamic facial affect processing in schizophrenia: Evidence of a double dissociation?, Schizophrenia Bulletin [P], vol 36, issue 4, Oxford University Press, UK, pp. 680-687.

Addamo, P.K., Farrow, M.A., Hoy, K.E., Bradshaw, J.L., Georgiou-Karistianis, N., 2009, A developmental study of the influence of task characteristics on motor overflow, Brain and Cognition, vol 69, Academic Press, USA, pp. 413-419.

Fitzgerald, P.B., Hoy, K.E., McQueen, S.A., Maller, J.J., Herring, S.E., Segrave, R.A., Bailey, M.J., Been, G., Kulkarni, J., Daskalakis, Z.J., 2009, A randomized trial of rTMS targeted with MRI based neuro-navigation in treatment-resistant depression, Neuropsychopharmacology [P], vol 34, issue 5, Nature Publishing Group, UK, pp. 1255-1262.

Fitzgerald, P.B., Hoy, K.E., Daskalakis, Z.J., Kulkarni, J., 2009, A randomized trial of the anti-depressant effects of low- and high-frequency transcranial magnetic stimulation in treatment-resistant depression, Depression And Anxiety [P], vol 26, issue 3, John Wiley & Sons, Inc., USA, pp. 229-234.

Fitzgerald, P.B., Mellow, T.B., Hoy, K.E., Segrave, R.A., Cooper, N.R., Upton, D.J., Croft, R., 2009, A study of intensity dependence of the auditory evoked potential (IDAEP) in medicated melancholic and non-melancholic depression, Journal of Affective Disorders [P], vol 117, issue 3, Elsevier BV, Netherlands, pp. 212-216.

Fitzgerald, P.B., McQueen, S.A., Herring, S.E., Hoy, K.E., Segrave, R.A., Kulkarni, J., Daskalakis, Z.J., 2009, A study of the effectiveness of high-frequency left prefrontal cortex transcranial magnetic stimulation in major depression in patients who have not responded to right-sided stimulation, Psychiatry Research [P], vol 169, issue 1, Elsevier Ireland Ltd, Ireland, pp. 12-15.

Fitzgerald, P.B., Maller, J.J., Hoy, K.E., Thomson, R.H.S., Daskalakis, Z.J., 2009, Exploring the optimal site for the localization of dorsolateral prefrontal cortex in brain stimulation experiments, Brain Stimulation [P], vol 2, issue 4, Elsevier Inc., USA, pp. 234-237.

Fitzgerald, P.B., Maller, J.J., Hoy, K.E., Farzan, F., Daskalakis, Z.J., 2009, GABA and cortical inhibition in motor and non-motor regions using combined TMS-EEG: A time analysis, Clinical Neurophysiology [P], vol 120, Elsevier, Ireland, pp. 1706-1710.

Hoy, K.E., Georgiou-Karistianis, N., Farrow, M.A., Fitzgerald, P.B., 2009, Neurological soft signs in schizophrenia: Investigating motor overflow, World Journal of Biological Psychiatry, vol 10, Informa Healthcare, UK, pp. 763-771.

Addamo, P.K., Farrow, M., Hoy, K.E., Bradshaw, J.L., Georgiou-Karistianis, N., 2009, The influence of task characteristics on younger and older adult motor overflow, The Quarterly Journal of Experimental Psychology, vol 62, Psychology Press, UK, pp. 239-247.

Fitzgerald, P.B., Herring, S.E., Hoy, K.E., McQueen, S.A., Segrave, R.A., Kulkarni, J., Daskalakis, Z., 2008, A study of the effectiveness of bilateral transcranial magnetic stimulation in the treatment of the negative symptoms of schizophrenia, Brain Stimulation, vol 1, issue 1, Elsevier Inc., Netherlands, pp. 27-32.

Hoy, K.E., Georgiou-Karistianis, N., Laycock, R., Fitzgerald, P.B., 2008, A transcranial magnetic stimulation study of transcallosal inhibition and facilitation in schizophrenia, Journal of Clinical Neuroscience, vol 15, issue 8, Churchill Livingstone, UK, pp. 863-867.

Fitzgerald, P.B., Daskalakis, Z., Hoy, K.E., Farzan, F., Upton, D., Cooper, N.R., Maller, J.J., 2008, Cortical inhibition in motor and non-motor regions: A combined TMS-EEG study, Clinical EEG and Neuroscience, vol 39, issue 3, Electroencephalography and Clinical Neuroscience Society, USA, pp. 112-117.

Enticott, P.G., Johnston, P., Herring, S.E., Hoy, K.E., Fitzgerald, P.B., 2008, Mirror neuron activation is associated with facial emotion processing, Neuropsychologia, vol 46, issue 11, Pergamon, UK, pp. 2851-2854.

Fitzgerald, P.B., Hoy, K.E., McQueen, S.A., Herring, S.E., Segrave, R.A., Been, G., Kulkarni, J., Daskalakis, Z.J., 2008, Priming stimulation enhances the effectiveness of low-frequency right prefrontal cortex transcranial magnetic stimulation in major depression, Journal Of Clinical Psychopharmacology [P], vol 28, issue 1, Lippincott Williams & Wilkins, USA, pp. 52-58.

Enticott, P.G., Hoy, K.E., Herring, S.E., Johnston, P., Daskalakis, Z., Fitzgerald, P.B., 2008, Reduced motor facilitation during action observation in schizophrenia: A mirror neuron deficit?, Schizophrenia Research, vol 102, issue 1-3, Elsevier BV, Netherlands, pp. 116-121.

Johnston, P., Enticott, P.G., Mayes, A.K., Hoy, K.E., Herring, S.E., Fitzgerald, P.B., 2008, Symptom correlates of static and dynamic facial affect processing in schizophrenia: Evidence of a double dissociation?, Schizophrenia Bulletin, vol E, Oxford University Press, England, pp. 1-8.

Fitzgerald, P.B., Fountain, S., Hoy, K.E., Maller, J.J., Enticott, P.G., Laycock, R., Upton, D., Daskalakis, Z.J., 2007, A comparative study of the effects of repetitive paired transcranial magnetic stimulation on motor cortical excitability, Journal of Neuroscience Methods, vol 165, issue 2, Elsevier Science, The Netherlands, pp. 265-269.

Addamo, P.K., Farrow, M., Hoy, K.E., Bradshaw, J.L., Georgiou-Karistianis, N., 2007, The effects of age and attention on motor overflow production-A review, Brain Research Reviews, vol 54, issue 1, Elsevier Science BV, The Netherlands, pp. 189-204.

Hoy, K.E., Georgiou-Karistianis, N., Laycock, R., Fitzgerald, P.B., 2007, Using transcranial magnetic stimulation to investigate the cortical origins of motor overflow: a study in schizophrenia and healthy controls, Psychological Medicine, vol 37, issue 4, Cambridge University Press, USA, pp. 583-594.

Baliz, Y., Armatas, C., Farrow, M.A., Hoy, K.E., Fitzgerald, P.B., Bradshaw, J.L., Georgiou-Karistianis, N., 2005, The influence of attention and age on the occurrence of mirror movements, Journal of the International Neuropsychological Society, vol 11, issue 7, Cambridge University Press, New York USA, pp. 855-862.

Hoy, K.E., Fitzgerald, P.B., Bradshaw, J.L., Armatas, C.A., Georgiou-Karistianis, N., 2004, Investigating the cortical origins of motor overflow, Brain Research Reviews, vol 46, issue 3, Elsevier, Amsterdam The Netherlands, pp. 315-327.

Georgiou-Karistianis, N., Hoy, K.E., Bradshaw, J.L., Farrow, M.A., Chiu, E., Churchyard, A.J., Fitzgerald, P.B., Armatas, C.A., 2004, Motor overflow in Huntington's disease, Journal of Neurology Neurosurgery and Psychiatry, vol 75, issue 6, BMJ Publishing Group, London UK, pp. 904-906.

Hoy, K.E., Fitzgerald, P.B., Bradshaw, J.L., Farrow, M.A., Brown, T.L., Armatas, C.A., Georgiou-Karistianis, N., 2004, Motor overflow in schizophrenia, Psychiatry Research, vol 125, issue 2, Elsevier, Ireland, pp. 129-137.

Conference Proceedings

Hoy, K.E., Fitzgerald, P.B., Georgiou-Karistianis, N., 2005, Using transcranial magnetic stimulation to investigate the cortical origins of motor overflow in schizophrenia, Australian and New Zealand Journal of Psychiatry, 7 December 2005 - 9 December 2005, Blackwell Publishing, Australia, p. A60.

Postgraduate Research Supervisions

Current Supervision

Program of Study:
(DOCTORATE BY RESEARCH).
Thesis Title:
Cortical inhibition and working memory in the pathophysiology and genetics of schizophrenia.
Supervisors:
Fitzgerald, P (Joint), Hoy, K (Joint-co).
Program of Study:
(DOCTORATE BY RESEARCH).
Thesis Title:
Impaired social cognition in schizophrenia and bipolar affective disorder: A mirror neuron deficit?.
Supervisors:
Fitzgerald, P (Main), Enticott, P (Associate), Hoy, K (Associate).
Program of Study:
(DOCTORATE BY RESEARCH).
Thesis Title:
Investigating the neural correlates of brain stimulation on neurocognition..
Supervisors:
Fitzgerald, P (Main), Hoy, K (Associate).
Program of Study:
(DOCTORATE BY RESEARCH).
Thesis Title:
The neurophysiological mechanisms underlying the therapeutic effects of TMS for TRD.
Supervisors:
Fitzgerald, P (Main), Hoy, K (Associate).

Completed Supervision

Student:
Bailey, N.
Program of Study:
Changes in neural activity in major depressive disorder following a traumatic brain injury. (PHD) 2012.
Supervisors:
Fitzgerald, P (Main), Hoy, K (Associate).
Student:
Furtado, C.
Program of Study:
Structural and neurocognitive correlates of treatment resistant depression: from acute illnes to symptomatic recovery. (PHD) 2012.
Supervisors:
Fitzgerald, P (Main), Hoy, K (Associate), Maller, J (Associate), Savage, G (Associate).