Extinction – an underdiagnosed phenomenon

Rev PR Case Report

Patrick UrwinNeurology ST3

• 48 yr old R handed Reverend

• Visiting Nottingham

• Found unresponsive in bath 24/03/12

• Left hemiparesis

• Left hemisensory deficit

• No PMHx / DHx

• Rare EtOH / Non-smoker

• FHx mother DVT post partum

Clinical Course

• CT brain

• CT angio distal right ICA occlusion

• Thrombolysed

CT Brain 24hr post thrombolysis

T2

DWI

ADC

MRI Brain on Day 5 post infarct

Repatriation

• Kingston Wd K&C 17/04/12 for rehabilitation

• Femoral DVT 24/04/12

• Enoxaparin

• Warfarin commenced after 4/52

• Vasculitis and thrombophilia screen negative

• Homonomous hemianopia and left neglect reported in notes

• Citalopram for post-stroke depression

• Transferred to NeuroRehab 15/06/12

• Normal visual fields on formal testing

Behavioural Assessment of Neglect, Azouvi

Forgets to groom or shave the left part of his/her face 1

Experiences difficulty in adjusting his/her left sleeve or slipper 3

Forgets to eat food on the left side of his/her plate 0

Forgets to clean the left side of his/her mouth after eating 3

Experiences difficulty in looking towards the left 3

Forgets about a left part of his/her body (e.g. forgets to put his/her upper limb on the armrest or his/her foot on the wheelchair rest, or forgets to use his/her left arm when he/she needs to)

3

Has difficulty in paying attention to noise ore people addressing him/her from the left 3

Collides with people or objects on the left side, such as doors or furniture (either while walking or driving a wheelchair)

0

Experiences difficulty in finding his/her way towards the left when travelling in familiar places or in the rehabilitation unit

n/a

Experiences difficulty finding his/her personal belongings in the room or bathroom when they are on the left side

2

18/30

Key: 0 = no neglect; 1= mild neglect; 2 = moderate neglect; 3 = severe neglect

* *

49935

Extinction testing

• Computerised test

– Attention paid to centre of screen

– Series of numbers displayed centrally

– * flash up in peripheries up to two quadrants 100ms

– Pt reports when * seen and where

– Errors/omission noted

• All omissions by PR on left when concurrent R stimulus

Search testing

• Alternative task

• Inverted T present in 50%

• Pt reports present or absent

• Observer records present on L, R or absent and calculates accuracy

GVS Trial

• PR given GVS by Dr. Wilkinson's team

• Baseline measures Aug 2012

• Repeat at 1/52 following sham GVS

• 2 further assessments after 5/7 GVS and 2/52 after

• Increasing evidence of GVS benefit in neglect

• E.g. Utz et al. Neuropsychologia. 2011 Apr;49(5):1219-25:

“In neglect patients [...] GVS significantly

reduced the rightward line bisection error

as compared to baseline (without GVS)

and sham stimulation”

• Unfortunately minimal benefit in PR's extinction

• No improvement on computerised stimulus testing with *

• Transient improvement in search task at end of GVS

– Back to pre-GVS baseline after 1/52

– No residual improvement in extinction when pt discharged to intermediate care Sept 2012

Neglect

● Graded defect

– Gradually declining awareness or performance moving towards contralesional side

– Depends on head and thorax position

● Cf field loss (1° visual cortex)

– Clear borders, dependent on retinal position

● Parietal spatial mapping

– But loss of location in space causes loss of awareness of existence of items

– Loss of other modalities of sensory information does not cause neglect

– Is parietal function in attention to identify single next visual target?

Extinction

● No neglect when single stimulus offered

● Requires multiple stimuli

– Ipsilesional stimulation results in neglect of contralesional side

– Relative relation between stimuli, even if both contralesional

● Extinction less pronounced for stimuli with parallel pathways

– Contralesional faces – fusiform gyrus

– Contralesional spiders – limbic / amydala

• Extinction in healthy subjects

Extinction vs Neglect

●?Spectrum

●?Different anatomy– Right inferior parietal lobe, affecting both

dorsal and ventral visual processing pathways; implicated in both processes

– No consensus in literature for anatomical explanation

Extinction vs Neglect

● Why make the diagnosis?

– Poorer prognosis in stroke pts with neglect

– Tailored MDT rehab improves outcome in some patients with neglect

– Potentially greater benefit with extinction therapy

● Do we miss many?

– up to 75% of pts with hemiparesis have neglect or extinction

● Extinction can still have profound impact

– Shopping

– Driving

– Crossing road

Kerkhoff et al. demonstrated a sustained improvement in tactile extinction in 2 patient with chronic deficits following GVS

Unfortunately, we have not demonstrated the same improvement with visual extinction in PR

Could there be a role of GVS in diagnosis of visual extinction?

Thanks to

Dr David Wilkinson, Senior Lecturer in Psychology

& Olga Zubko, Research Associate

References

• Driver J,Vuilleumier P. Perceptual awareness and its loss in unilateral neglect and extinction. Cognition. 2001; 79: 39-88.

• Kerkhoffa G, Hildebrandtb H, Reinharta S, Kardinala M, Dimovaa V, Utz KS. A long-lasting improvement of tactile extinction after galvanic vestibular stimulation: Two Sham-stimulation controlled case studies. Neuropsychologia. 2011 Jan; 49(2): 186–195

• Utz KS, Keller I, Kardinal M, Kerkhoff G. Galvanic vestibular stimulation reduces the pathological rightward line bisection error in neglect-a sham stimulation-controlled study. Neuropsychologia. 2011 Apr; 49(5): 1219-25.

• Vossel S, Eschenbeck P, Weiss PH, Weidner R, Saliger J, Karbe H, Fink GR. Visual extinction in relation to visuospatial neglect after right-hemispheric stroke: quantitative assessment and statistical lesion-symptom mapping. J Neurol Neurosurg Psychiatry. 2011; 82: 862-868.

• Wilkinson D, Zubko O, Degutis J, Milberg W, Potter J. Improvement of a figure copying deficit during subsensory galvanic vestibular stimulation. J Neuropsychol. 2010 Mar; 4(1):107-18.