Dr. Verner Knott

Talking Down the Voices: A Pilot Study on the Neural, Behavioural and Functional Outcome of Cognitive Therapy for Auditory Hallucinations

hayley — Thu, 06 Jun 2013 19:34:00 +0000

Auditory verbal hallucinations (AVHs) are a characteristic symptom of schizophrenia (SZ) but the neurological and cognitive mechanisms underlying this symptom remains poorly understood. Neuroimaging and neuroelectrophysiological studies with event-related potentials (ERPs) suggest that internal voices may arise from aberrant activity in sound/speech perception neurocircuitry, which usurps resources required for efficient sensory-level and higher order processing of external stimuli, functions that are integral for normal social cognition and daily functioning. 36 SZ patients with consistent history of AVHs will be included in this parallel group design where half the patients will be randomly assigned to receive cognitive behavioural therapy for voices (CBTv) treatment for 5 weeks followed by therapy as usual (TAU) for 5 months, whereas, the remaining 18 will receive the treatment in reverse order. Healthy participants (n = 18) will be included to act as the healthy control group. The objective of this pilot study is to examine the effects CBTv, and to evaluate the effects of CBTv on the mismatch negativity (MMN), in ERP indexing early auditory processing, cognition and functioning in SZ.

A Pilot Study Using an NMDA Antagonist to Modulate Transcranial Direct Current Stimulation (tDCS)’s Effects on Auditory Sensory Memory Processing

hayley — Thu, 06 Jun 2013 19:18:03 +0000

Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation which uses a very weak constant current to temporarily excite the brain area of interest via small electrodes placed on the scalp. Currently, tDCS is being used as a tool to investigate and improve motor and cognitive function. tDCS-induced increases in neuronal excitability and performance improvements have been observed following anodal stimulation of brain regions associated with visual and motor functions, but relatively little research has been conducted with respect to areas associated with auditory processing. Recently, pilot study results indicate that anodal tDCS can increase auditory sensory processing, wheras cathodal tDCS decreases auditory processing, as measured by a brain-based event-related potential (ERP), mismatch negativity (MMN). As research has shown that tDCS lasting effects may be dependant on N-methyl-D-aspartate (NMDA) receptor activity, the current study will investigate the use of an NMDA antagonist, dextromethorphan (DMO), to assess possible modulation of tDCS’ effects on MMN, which is also thought to be NMDA function dependant. tDCS is a possible treatment for sensory processing deficits in psychiatric and neurological disorders and result from this study will contribute to the understanding of underlying neurobiological mechanisms mediating sensory improvements.

Assessment of Transcranial Direct Current Stimulation (tDCS)’s Effects on Sensory Processing Dysfunction in Schizophrenia: A Pilot Study

hayley — Thu, 06 Jun 2013 19:14:09 +0000

Cognitive impairment, characterized by deficits in perception, attention, memory and executive functions, has been proposed to be the core feature in schizophrenia (SZ). Transcranial direct current stimulation (tDCS) is a quick, non-invasive form of brain stimulation which uses a very weak constant current to temporarily excite the brain area of interest via small electrodes placed on the scalp. Short sessions of tDCS treatment have been found to improve motor and cognitive function in healthy controls and in neurological and psychiatric patients with cognitive deficits, including recently, in schizophrenia. Studies which have used tDCS to improve frontal cognition or specifically hallucination symptoms, have found significant improvement in cognitive symptoms following treatment. Recently, pilot study results demonstrate that anodal tDCS increases auditory sensory processing, whereas cathodal tDCS can decrease auditory processing, as measured by a brain-based event-related potential (ERP), mismatch negativity (MMN). A deficient MMN is a biomarker of schizophrenia and indexes deficient auditory sensory processing in this population. A hypofunctional N-methyl-D-aspartate (NMDA) system is thought to be one of the main underlying mechanisms of schizophrenia and has been shown to contribute to reductions in MMN generation. Recent pharmacological studies have shown that tDCS-induced cortical activation is mediated in part by NMDA receptor activity. As NDMA receptors have been proposed as a target for treatment of schizophrenia cognition, this pilot study will assess the effects of anodal tDCS on MMN-indexed deficient sensory memory processing in schizophrenia patients.

JAWORSKA, N., DE SOMMA, E., BLONDEAU, C., TESSIER, P., NORRIS, S., FUSEE, W., BLIER, P., KNOTT, V. (2013).

hayley — Mon, 20 May 2013 21:42:52 +0000

The auditory P3 in antidepressant pharmacotherapy treatment responders, non-responders and controls. European Neuropsychopharmacology, 2013, [In press].

JAWORSKA, N., BERRIGAN, L., AHMED, A. G., GRAY, J., BRADFORD, J., KOROVESSIS, A., FEDOROFF, P., KNOTT, V. (2013).

hayley — Sun, 12 May 2013 21:49:28 +0000

The resting electrophysiological profile in adults with ADHD and co-morbid dysfunctional anger: A pilot study. Journal of Clinical Neurophysiology, 2013, [Epub ahead of print].

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IMPEY, D., CHIQUE-ALFONZO, M., FISHER, D., SHAH, D., KNOTT, V. J. (2013).

hayley — Fri, 12 Apr 2013 21:45:02 +0000

Effects of nicotine on visuospatial attentional orienting in non-smokers. Pharmacology Biochemistry and Behavior, 2013, [Epub ahead of print].

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SMITH, D. M., GRANT, B., FISHER, D. J., BORRACCI, G., LABELLE, A., KNOTT, V. J. (2013).

hayley — Mon, 11 Mar 2013 14:09:13 +0000

Auditory verbal hallucinations in schizophrenia correlate with P50 gating. Clinical Neurophysiology, 2013, [Epub ahead of print].

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JAWORSKA, N., BLIER, P., FUSEE, W., KNOTT, V.J. (2012).

hayley — Tue, 12 Feb 2013 21:36:22 +0000

Alpha power, alpha asymmetry and anterior cingulate cortex activity in depressed males and females. Journal of Psychiatric Research, 46(11), 1483-1491.

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JOBERT, M., WILSON, F.J., RUIGT, G.S., BRUNOVSKY, M., PRICHEP, L.S., DRINKENBURG, W.H., BABILONI, C., BOEIJINGA, P.H., VAN GERVEN, J.M., HIRATA, K., HERGERL, U., KINOSHITA, T., KNOTT, V.J., LOPES DA SILVA, F.H., MATOUSEK, M., MUCCI, A., NOTTAGE, J.F., OLBRICH, S., SALETU, B., STANCAK, A., STRIK, W.K., WISE, R.G. (2012).

hayley — Tue, 12 Feb 2013 20:10:18 +0000

Guidelines for the recording and evaluation of pharmaco-EEG data in man: The International Pharmaco-EEG Society (IPEG). Neuropsychobiology, 66(4), 201-220.

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FISHER, D.J., LABELLE, A., KNOTT, V.J. (2012).

hayley — Tue, 12 Feb 2013 20:04:39 +0000

Alterations of mismatch negativity (MMN) in schizophrenia patients with auditory hallucinations experiencing acute exacerbation of illness. Schizophrenia Research, 139(1-3), 237-245.

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