The impact of low-frequency stimulation of the pedunculopontine nucleus region on reaction time in parkinsonism

Thevathasan, W, Silburn, PA, Brooker, H, Coyne, TJ, Khan, S, Gill, SS, Aziz, TZ and Brown, P (2010) The impact of low-frequency stimulation of the pedunculopontine nucleus region on reaction time in parkinsonism. Journal of Neurology, Neurosurgery and Psychiatry, 81 10: 1099-1104. doi:10.1136/jnnp.2009.189324

Author Thevathasan, W
Silburn, PA
Brooker, H
Coyne, TJ
Khan, S
Gill, SS
Aziz, TZ
Brown, P
Title The impact of low-frequency stimulation of the pedunculopontine nucleus region on reaction time in parkinsonism
Journal name Journal of Neurology, Neurosurgery and Psychiatry   Check publisher's open access policy
ISSN 0022-3050
Publication date 2010-10
Sub-type Article (original research)
DOI 10.1136/jnnp.2009.189324
Volume 81
Issue 10
Start page 1099
End page 1104
Total pages 6
Place of publication London, United Kingdom
Publisher BMJ Group
Collection year 2011
Language eng
Formatted abstract
Objectives: Attentional augmentation and enhanced motor function are potential mechanisms by which stimulation of the region of the pedunculopontine nucleus (PPN) may improve gait in parkinsonism. Here, the authors assess the impact of stimulation of this region on attentional and motor aspects of reaction task performance in patients with parkinsonism.

Methods: Eleven patients implanted with PPN stimulators underwent computerised assessment of simple, choice and digit vigilance reaction tasks. Patients were assessed 'off medication' during stimulation at different frequencies (0 Hz, 5 Hz, 10 Hz and 'therapeutic' 20-35 Hz). There were two primary endpoints: 'Speed of Reaction' (sum of the mean task reaction times) and 'Accuracy of Reaction' (reflecting omissions and percentage of correct responses). Baseline performance was compared with age- and sex-matched healthy controls. Clinical effects of stimulation were assessed using the Unified Parkinson's Disease Rating Scale and a falls frequency scale.

Compared with healthy controls, subjects had significant deficits in 'Speed of Reaction' and in all mean task reaction times. 'Accuracy of Reaction' was not different from healthy controls and did not improve with stimulation. 'Speed of Reaction' significantly improved with stimulation at therapeutic frequencies (20e35 Hz). Of the individual tasks, only simple reaction time improved significantly. Simple reaction time distribution analysis revealed a general speeding of responses rather than a selective reduction in outliers. Acute PPN stimulation improved gait and balance but not akinesia scores. Chronic PPN stimulation significantly improved falls frequency. Falls score improvement significantly correlated with changes to simple reaction time with therapeutic stimulation.

Conclusion: The pattern of reaction time improvement with stimulation of the PPN area suggests a benefit on motor performance, rather than augmentation of attention.
Keyword Deep brain-stimulation
Tegmental nucleus
Cognitive function
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: UQ Centre for Clinical Research Publications
Official 2011 Collection
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Citation counts: TR Web of Science Citation Count  Cited 30 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 34 times in Scopus Article | Citations
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Created: Sun, 17 Oct 2010, 00:07:07 EST