can the mind believe what the eye sees
TRANSCRIPT
Prof. A.V. SRINIVASAN.
M.D, D.M, PhD, F.I.A.N, F.A.A.N,
EMERITUS PROFESSOR OF NEUROLOGY
FORMER HEAD AND PROFESSOR OF NEUROLOGY
Institute of Neurology
Chennai
Prof. A.V. SRINIVASAN.
M.D, D.M, PhD, F.I.A.N, F.A.A.N,
EMERITUS PROFESSOR OF NEUROLOGY
FORMER HEAD AND PROFESSOR OF NEUROLOGY
Institute of Neurology
Chennai
The sign wasn’t placed there
By the Big Printer in the sky
NEU CON NEU CON
NeuNeuConConCONTROVERSIES IN NEUROLOGYCONTROVERSIES IN NEUROLOGY
APRIL 3-4, 2010APRIL 3-4, 2010
G.ARJUNDASG.ARJUNDAS
Shri Uttambhai Nathalal Mehta1924 - 1998
A visionary par excellence
The pioneer of neuropsychiatry in India
The mind behind some of the blockbuster drugs in the neuropsychiatry segment; the founder and guiding force behind Torrent Group
A perfect epitome of business excellence, scientific integrity and benevolence unparalleled
SHRI US MEHTA ORATION
Thomas ElbertThomas Elbert
Cortical representation expands linearly with Cortical representation expands linearly with
use.use.
Synchronous inputs lead to fusion of cortical Synchronous inputs lead to fusion of cortical zoneszones
Asynchronous inputs lead to segregation of Asynchronous inputs lead to segregation of cortical zonescortical zones..
Disuse or De-afferentation leads to invasion of Disuse or De-afferentation leads to invasion of
unused cortical area by nearby neurons.unused cortical area by nearby neurons.
Basic Basic PrinciplesPrinciples
Sensory modulation in spatial Sensory modulation in spatial neglectneglect
Peripheral somatosensory- Magnetic Peripheral somatosensory- Magnetic stimulationstimulation
Repetitive optokinetic stimulation Repetitive optokinetic stimulation
Neck Vibration trainingNeck Vibration training
Drug Treatment is currently unsuccessful
Novel TechniquesNovel Techniques
Sensory modulation and Sensory modulation and StrokeStroke
Rehabilitation aimed to increase use of Rehabilitation aimed to increase use of paretic handparetic hand
Virtual reality Virtual reality
Motor imagery Motor imagery
Prof. Prof. V.S..Ramachandran’sV.S..Ramachandran’s virtual reality virtual reality boxbox
Phantom limb phenomenon Phantom limb phenomenon
Other techniquesOther techniques
Caloric tests for balanceCaloric tests for balance Brings awareness of illness to patient.Brings awareness of illness to patient.
Kinesthetic, visual, and auditory Kinesthetic, visual, and auditory cues to improve Parkinsonian gait.cues to improve Parkinsonian gait.
INTERMANUAL REFERRAL OF INTERMANUAL REFERRAL OF SENSATION AND EXTINCTION OF SENSATION AND EXTINCTION OF PAIN IN PERIPHERAL AND PAIN IN PERIPHERAL AND CENTRAL LESIONS OF SOMATO CENTRAL LESIONS OF SOMATO SENSORY SYSTEMSENSORY SYSTEM
INTERMANUAL REFERRAL OF INTERMANUAL REFERRAL OF SENSATION AND EXTINCTION OF SENSATION AND EXTINCTION OF PAIN IN PERIPHERAL AND PAIN IN PERIPHERAL AND CENTRAL LESIONS OF SOMATO CENTRAL LESIONS OF SOMATO SENSORY SYSTEMSENSORY SYSTEM
BACKGROUNDBACKGROUND
Allesthesia and extinction of referral Allesthesia and extinction of referral sensation in brachial plexus lesions sensation in brachial plexus lesions A.V. Srinivasan and V.S. Ramachandran et al A.V. Srinivasan and V.S. Ramachandran et al (1998) (1998)
Intermanual referral of sensations Intermanual referral of sensations after central lesions of the somato after central lesions of the somato sensory system sensory system K. Sathian et al (2000) K. Sathian et al (2000)
METHODS METHODS
8 patients (19-51 years)8 patients (19-51 years) Brachial plexus lesion Brachial plexus lesion – one– one AmputationAmputation – two– two StrokeStroke – five– five
Patients were video filmed in the Patients were video filmed in the movement disorder clinic. Pinprick, cold, movement disorder clinic. Pinprick, cold, vibration and kinesthesis were testedvibration and kinesthesis were tested
MRI & ENMG in all cases MRI & ENMG in all cases
CENTRAL LESIONCENTRAL LESION
StrokeStrokeThalamic stroke Thalamic stroke - three- threeTemparo parietalTemparo parietal - two- two
Three to four months laterThree to four months later
Ipsilateral arm Ipsilateral arm - no referral- no referral to legto leg
STROKE STROKE Contd…Contd…
Intense pressure on the normal hand Intense pressure on the normal hand
resulted in extinction of pain in the resulted in extinction of pain in the
stroke sidestroke side
Pain returned within one Pain returned within one
minute of the pressure minute of the pressure
Intense pressure improved Intense pressure improved
sensory and motor sensory and motor
phenomenonphenomenon
AMPUTATIONAMPUTATION
Both the patients (below Both the patients (below
elbow & knee amputation) elbow & knee amputation)
showed intermanual showed intermanual
referral of sensation within referral of sensation within
10 days. The referred 10 days. The referred
sensations of touch and sensations of touch and
vibration lacked spatial vibration lacked spatial
organization and poor organization and poor
localization with a localization with a
relatively high threshold relatively high threshold
CASE VIGNETTE (BRACHIAL PLEXUS CASE VIGNETTE (BRACHIAL PLEXUS LESION)LESION)
21 year old girl, after total 21 year old girl, after total
brachial plexus lesion was brachial plexus lesion was
examined 6 months, 1 ½ & examined 6 months, 1 ½ &
2 ½ years after the lesion2 ½ years after the lesion
She had sensations She had sensations
intermanually referred in a intermanually referred in a
topographically organized topographically organized
manner in the phantom manner in the phantom
limb limb
INTERMANUAL REFERAL AND EXTINCTION OF INTERMANUAL REFERAL AND EXTINCTION OF PAIN SENSATIONPAIN SENSATION
Hemiparesis with Hemiparesis with hemisensory hemisensory
deficitdeficitAmputationAmputation
Brachial Brachial plexusplexus
Spatial organi-Spatial organi-sationsation
PoorPoor PoorPoor ExcellentExcellent
LocalisationLocalisation GoodGood PoorPoor ExcellentExcellent
Time of Time of occuranceoccurance
After 3 to 4 After 3 to 4 monthsmonths
Immediate Immediate with in 7 with in 7
daysdays
Immediate Immediate with in with in 7days7days
PainPainExtinction Extinction
After a delay of After a delay of
3 - 5 seconds3 - 5 secondsImmediateImmediate ImmediateImmediate
DISCUSSIONDISCUSSION
Anatomical facts Anatomical facts
1. Primary somato sensory area 3b1. Primary somato sensory area 3b
2. A. Primary somato sensory area 1 & 22. A. Primary somato sensory area 1 & 22. B. Second somato sensory cortex and 2. B. Second somato sensory cortex and
parietal operculumparietal operculum
In 2a & 2b the receptive fields are largerIn 2a & 2b the receptive fields are largerbilateral and callosal connection arebilateral and callosal connection areabundant abundant
DISCUSSION DISCUSSION Contd…Contd…
Contralateral referral of sensations Contralateral referral of sensations
was not found in normal subjects or in was not found in normal subjects or in
hemiparetic patients without hemi hemiparetic patients without hemi
sensory losssensory loss
Neural mechanisms for perceptual Neural mechanisms for perceptual
alteration not clear alteration not clear
It appears that a decrease It appears that a decrease in somatosensory input to in somatosensory input to one cerebral hemisphere one cerebral hemisphere from the contralateral hand from the contralateral hand allows responsiveness of allows responsiveness of neurons in this hemisphere neurons in this hemisphere to moderately intense to moderately intense tactile stimuli on the tactile stimuli on the ipsilateral hand to exceed ipsilateral hand to exceed perceptual threshold perceptual threshold (which does not normally (which does not normally occur).occur).
DISCUSSION DISCUSSION Contd…Contd…
CONCLUSIONCONCLUSION
Intermanual referral & extinction of pain Intermanual referral & extinction of pain occurred immediately in amputation and occurred immediately in amputation and brachial plexus lesions and after a delay brachial plexus lesions and after a delay in strokein stroke
Intermanual referral of sensation Intermanual referral of sensation occurred topographicaly organised occurred topographicaly organised manner in brachial plexus lesions but not manner in brachial plexus lesions but not in amputation and strokein amputation and stroke
Hemineglect Hemineglect An Interesting Case An Interesting Case
fromfromProf.A.V.Srinivasan’s Prof.A.V.Srinivasan’s
UnitUnit
Can the mind believe Can the mind believe what the eye sees ?what the eye sees ?
On vision, visuospatial On vision, visuospatial
dysfunction and body image dysfunction and body image
perception in right perception in right
hemispherical dysfunctionhemispherical dysfunctionDr.K.Bijoy MenonDr.K.Bijoy Menon (Senior Resident)(Senior Resident)
Dr.Sundar, Dr.Saravanan, Dr.Sundar, Dr.Saravanan, Dr.RamakrishnanDr.Ramakrishnan
Dr.Nithyanandan (Asst.Prof) , Dr.Nithyanandan (Asst.Prof) ,
Prof. A.V.SrinivasanProf. A.V.Srinivasan
We thankWe thank Prof. V.S.RamachandranProf. V.S.Ramachandran, M.D., Ph.D., , M.D., Ph.D.,
Director Director
Centre for Brain and Cognitive Sciences Centre for Brain and Cognitive Sciences
University of California, San Diego, USAUniversity of California, San Diego, USA
Indrani. 50 year old femaleIndrani. 50 year old female
Presents with sudden onset of Presents with sudden onset of weakness of left upper and lower weakness of left upper and lower limblimb
O/E. O/E. Conscious, oriented to time, place and Conscious, oriented to time, place and
person person Mild left UMN facial paresisMild left UMN facial paresisLeft hemiplegiaLeft hemiplegiaAll peripheral pulses palpable All peripheral pulses palpable
CT Brain – P – Shows a (R) CT Brain – P – Shows a (R) Occipitotemporal infarctOccipitotemporal infarct
Higher mental function evaluation Higher mental function evaluation
MMSE : 28/30MMSE : 28/30
She was very attentive and quite clear in She was very attentive and quite clear in her conversation with us, though she her conversation with us, though she would be complaining of a vague left sided would be complaining of a vague left sided shoulder painshoulder pain
On lobar testing, she hadOn lobar testing, she had
Left visual neglect with (L) hemianopiaLeft visual neglect with (L) hemianopia
No auditory neglectNo auditory neglect
Absent sensory perception in (L) upper Absent sensory perception in (L) upper limb and (L) tactile neglect in the lower limb and (L) tactile neglect in the lower limb limb
On cold caloric tests and its effect on neglectOn cold caloric tests and its effect on neglect
Video of NeglectVideo of Neglect
Video of caloric test and NystagmusVideo of caloric test and Nystagmus
Video of disappearance of neglect Video of disappearance of 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
On Anosognosia, Body neglect On Anosognosia, Body neglect (Hemisomatognosia) and (Hemisomatognosia) and somatoparaphreniasomatoparaphrenia
Anosognosia – our patient has itAnosognosia – our patient has it
Body neglect by Bisiach’s test – our Body neglect by Bisiach’s test – our patient does not have itpatient does not have it
Somatoparaphrenia – our patient has itSomatoparaphrenia – our patient has it
SomatoparaphreniaSomatoparaphrenia
On the somatophrenic arm and mirrorsOn the somatophrenic arm and mirrors
On Allesthesia, tactile neglect and ‘blind On Allesthesia, tactile neglect and ‘blind
touch’touch’
‘‘Touch your left arm’ Bisiach’s test of body Touch your left arm’ Bisiach’s test of body
neglect.neglect.
Absent proprioception and touch in the left Absent proprioception and touch in the left
upper limbupper limb
Patient is still able to touch her left arm Patient is still able to touch her left arm
whatever position the examiner keeps the whatever position the examiner keeps the
arm in.arm in.
Blind Sight Vs Blind TouchBlind Sight Vs Blind Touch
On visual imagery, neglect and caloric On visual imagery, neglect and caloric
tests tests
Visual imageryVisual imagery
Bisiach’s testBisiach’s test
Our testOur test
ResultsResults
Unconscious awareness in a person with Unconscious awareness in a person with
Blind Sight Blind Sight
And And
Blind TouchBlind Touch
Conscious mind and unconscious mindConscious mind and unconscious mind
Theories of consciousness and the soul.Theories of consciousness and the soul.