Recovering Repressed Visual Memories and in Parietal Lobe Syndrome

Using Vestibular StimulationAuthors:

Srinivasan V. AvathvadiBijoy K. Menon | Nithyanandam V. Allimuthu

Rogers R. Diane | Ramachandran S. Vilayanur

Monday, October 9, 2006 Poster Session II

M48

Recovering Repressed Visual Memories and in Parietal Lobe

Syndrome Using Vestibular Stimulation

Srinivasan V. Avathvadi, Bijoy K. Menon, Rogers R. Diane, Ramachandran S. Vilayanur

and Nityanandam V. Allimuthu Neurology, Institute of Neurology, Madras Medical College, Chennai,

Tamilnadu, India; Centre for Brain and Cognition, University California - San Diego, San Diego, CA

Objective: 1)Does vestibular stimulation through caloric test reverse neglect, mental imagery tasks and mirror

agnosia? Background:Unilateral neglect may be temporarily reduced by vestibular stimulation. Designs/Methods:

Our patient had Left hemiplegia,visual neglect, anosognosia. CT Brain showed right occipitoparieto temporal

infarct.She reported and pointed objects kept to her right and left side of her room ,before, during and after cold

caloric testing. Mental imagery was tested by blindfolding her She reached for the reflection of a pencil in a mirror

placed on right and the pencil was on left (dubbedmirror agnosia by VS Ramachandran and E.Altschuler)

Results : First she reported objects placed on her right. When cold caloric test in her left ear produced

nystagmus,her neglect disappeared.She reported all objects, when mental imagery was tested.After thirty

minutes, she could report and point to objects on her right only. When caloric test was repeated and during

mental imagery,she reported all objects. It eliminated neglect but not mirror agnosia .Conclusion:a) vestibular

stimulation eliminates neglect for mental imagery giving access to previously repressed inaccessible memories b)

Mirror agnosia is caused by right parietal damage rather than being a direct consequence of neglect.

Authors: Srinivasan V. Avathvadi | Bijoy K. Menon | Rogers R. Diane

Ramachandran S. Vilayanur | Nithyanandam V. Allimuthu

Monday, October 9, 2006 Poster Session II

Recovering Repressed Visual Memories and in

Parietal Lobe Syndrome Using Vestibular Stimulation

Bijoy K. Menon Nithyanandam V. AllimuthuRogers R. DianeRamachandran S. Vilayanur

INSTITUTE OF NEUROLOGY

MADRAS MEDICAL COLLEGE,CHENNAI

October 09, 2006 - Chicago, USA

PROF.A.V.SRINIVASAN, MD, DM, Ph.D, F.A.A.N, F.I.A.N,

Introduction

NEGLECT Definition

Neglect has been defined as “the failure to report, respond, or orient to novel or meaningful stimuli presented to the side opposite a brain lesion, when this failure cannot be attributed to either sensory or motor defects.”

Category Memory and representational deficits Motor Neglect Sensory Neglect

NEGLECT - cont..

Anatomy Posterior parietal cortex, frontal lobe, cingulate gyrus,

striatum and thalamus. Explanation

Attentional orienting system Failure to construct a complete mental representation of

contralesional space Incidence

Stone et al 80% - visual neglect Denes et al 17% - unilateral spacial neglect – right CVA

Prognosis Poor outcome and lower scores on FIM

Does vestibular stimulation through caloric Does vestibular stimulation through caloric test reverse neglect, mental imagery tasks test reverse neglect, mental imagery tasks and mirror agnosia?and mirror agnosia?

Unilateral neglect may be temporarily Unilateral neglect may be temporarily reduced by vestibular stimulationreduced by vestibular stimulation

Objective and Background

Designs/Methods: Designs/Methods: Case Case vignettevignette

Our patient had Left Our patient had Left hemiplegia,visual neglect, hemiplegia,visual neglect, anosognosia. CT Brain showed anosognosia. CT Brain showed right occipitoparieto temporal right occipitoparieto temporal infarct. She reported and pointed infarct. She reported and pointed objects kept to her right and left objects kept to her right and left side of her room, before, during side of her room, before, during and after cold caloric testing. and after cold caloric testing.

Designs/Methods:Designs/Methods:

Mental imagery was tested by Mental imagery was tested by blindfolding her She reached for blindfolding her She reached for the reflection of a pencil in a mirror the reflection of a pencil in a mirror placed on right and the pencil was placed on right and the pencil was on left (dubbed mirror agnosia by on left (dubbed mirror agnosia by VS Ramachandran and E. VS Ramachandran and E. Altschuler) Altschuler)

On visual imagery, neglect and caloric tests On visual imagery, neglect and caloric tests

Visual imageryVisual imagery

Bisiach’s testBisiach’s test

Our testOur test

Video of caloric test and Nystagmus

Video of Neglect

Video of disappearanceof Neglect

On ‘ Mirror Agnosia’On ‘ Mirror Agnosia’Mirror Agnosia on the Right Mirror Agnosia on the Right

After caloric test, Mirror Agnosia on the LeftAfter caloric test, Mirror Agnosia on the Left

‘‘Mirror Agnosia’ to frontMirror Agnosia’ to front

Results :

First she reported objects placed on her right. When cold caloric test in her left ear produced nystagmus, her Neglect disappeared. She reported all objects, when mental imagery was tested.

Results :

After thirty minutes, she could report and point to objects on her right only. When caloric test was repeated and during mental imagery, she reported all objects. It eliminated neglect but not mirror agnosia.

Results

DiscussionDiscussion

Our patient had all the three major Our patient had all the three major categories of attentional deficit.categories of attentional deficit.

Vestibular stimulation improved all the Vestibular stimulation improved all the three categories temporarily till the three categories temporarily till the stimulation persisted.stimulation persisted.

After 30min - Neglect returnedAfter 30min - Neglect returned Mirror agnosia did not disappear.Mirror agnosia did not disappear.

Treatment of NeglectTreatment of Neglect

Attentional MechanismsAttentional Mechanisms– Training of attention - WeinvergTraining of attention - Weinverg– Activation of sustained attention systemActivation of sustained attention system

Representational Deficit – SmaniaRepresentational Deficit – Smania– Visual and movement imagery exercisesVisual and movement imagery exercises

Caloric Stimulation – Vallar GCaloric Stimulation – Vallar G– In our Patient, this stimulation are usedIn our Patient, this stimulation are used

DISCUSSION DISCUSSION – CONT..– CONT..

Galvanic Stimulation – RorsmanGalvanic Stimulation – Rorsman Neck muscle Propioception – KarnathNeck muscle Propioception – Karnath Prism Method – RossettiPrism Method – Rossetti Eye patch – Butter & KirchEye patch – Butter & Kirch Mirror Method – V S RamachandranMirror Method – V S Ramachandran

Treatment of NeglectTreatment of Neglect

DISCUSSION DISCUSSION – CONT..– CONT..

Remission of Neglect - Discussion

Neural pathways responsible for remission following vestibular stimulation through caloric stimulation are unknown

vestibular stimulation eliminates neglect for mental

imagery giving access to previously repressed

inaccessible memories

Mirror agnosia is caused by right parietal damage

rather than being a direct consequence of neglect.

Conclusion:

a) vestibular stimulation eliminates neglect for mental imagery giving access to previously repressed inaccessible memories

b) Mirror agnosia is caused by right parietal damage rather than being a direct consequence of neglect.

We ThankWe Thank

Prof. V.S.RamachandranProf. V.S.Ramachandran, , M.D., Ph.D.,M.D., Ph.D.,

DirectorDirector Centre for Brain and Cognitive Sciences Centre for Brain and Cognitive Sciences

University of California, San Diego, USAUniversity of California, San Diego, USA

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