1. The sign wasn’t placed there
By the Big Printer in the sky
Prof. A.V. SRINIVASAN.
Prof. A.V. SRINIVASAN.
M.D, D.M, PhD, F.I.A.N, F.A.A.N,
M.D, D.M, PhD, F.I.A.N, F.A.A.N,
EMERITUS PROFESSOR OF NEUROLOGY
EMERITUS PROFESSOR OF NEUROLOGY
FORMER HEAD AND PROFESSOR OF NEUROLOGY
FORMER HEAD AND PROFESSOR OF NEUROLOGY
Institute of Neurology
Chennai
Chennai

4. PROF V S RAMACHANDRAN

5. Thomas Elbert
Basic
Principles
Cortical representation expands linearly with use.
 Synchronous inputs lead to fusion of cortical zones
 Asynchronous inputs lead to segregation of cortical
zones.
Disuse or De-afferentation leads to invasion of
unused cortical area by nearby neurons.

6. Sensory modulation in spatial neglect
Novel Techniques
 Peripheral somatosensory- Magnetic
stimulation
 Repetitive optokinetic stimulation
 Neck Vibration training
Drug Treatment is currently unsuccessful

7. Sensory modulation and Stroke
 Rehabilitation aimed to increase use of
paretic hand
 Virtual reality
 Motor imagery
 Prof. V.S..Ramachandran’s virtual reality box
 Phantom limb phenomenon

8. Other techniques
 Caloric tests for balance
 Brings awareness of illness to patient.
 Kinesthetic, visual, and auditory cues to
improve Parkinsonian gait.

9. INTERMANUAL REFERRAL OF
SENSATION AND EXTINCTION OF
PAIN IN PERIPHERAL AND
CENTRAL LESIONS OF SOMATO
SENSORY SYSTEM

10. BACKGROUND
 Allesthesia and extinction of referral
sensation in brachial plexus lesions
A.V. Srinivasan and V.S. Ramachandran et al (1998)
 Intermanual referral of sensations after
central lesions of the somato sensory
system
K. Sathian et al (2000)

11. METHODS
8 patients (19-51 years)
 Brachial plexus lesion – one
 Amputation – two
 Stroke – five
 Patients were video filmed in the movement
disorder clinic. Pinprick, cold, vibration and
kinesthesis were tested
 MRI & ENMG in all cases

12. CENTRAL LESION
Stroke
Thalamic stroke - three
Temparo parietal - two
Three to four months later
Ipsilateral arm - no referral
to leg

13. STROKE Contd…
 Intense pressure on the normal hand resulted
in extinction of pain in the stroke side
 Pain returned within one
minute of the pressure
 Intense pressure improved
sensory and motor
phenomenon

14. AMPUTATION
 Both the patients (below
elbow & knee amputation)
showed intermanual referral of
sensation within 10 days. The
referred sensations of touch
and vibration lacked spatial
organization and poor
localization with a relatively
high threshold

15. CASE VIGNETTE (BRACHIAL PLEXUS
LESION)
 21 year old girl, after total
brachial plexus lesion was
examined 6 months, 1 ½ &
2 ½ years after the lesion
 She had sensations
intermanually referred in a
topographically organized
manner in the phantom limb

17. INTERMANUAL REFERAL AND EXTINCTION OF
PAIN SENSATION
Hemiparesis with Brachial
hemisensory deficit Amputation plexus
Spatial organi- Poor Poor Excellent
sation
Localisation Good Poor Excellent
Time of occurance After 3 to 4 months Immediate Immediate
with in 7 days with in 7days
Pain After a delay of Immediate Immediate
Extinction 3 - 5 seconds

18. DISCUSSION
Anatomical facts
1. Primary somato sensory area 3b
2. A. Primary somato sensory area 1 & 2
2. B. Second somato sensory cortex and
parietal operculum
In 2a & 2b the receptive fields are larger
bilateral and callosal connection are
abundant

19. DISCUSSION Contd…
 Contralateral referral of sensations was not
found in normal subjects or in hemiparetic
patients without hemi sensory loss
 Neural mechanisms for perceptual alteration
not clear

20. DISCUSSION Contd…
It appears that a decrease in
somatosensory input to one
cerebral hemisphere from the
contralateral hand allows
responsiveness of neurons in
this hemisphere to
moderately intense tactile
stimuli on the ipsilateral hand
to exceed perceptual
threshold (which does not
normally occur).

21. CONCLUSION
 Intermanual referral & extinction of pain
occurred immediately in amputation and
brachial plexus lesions and after a delay in
stroke
 Intermanual referral of sensation occurred
topographicaly organised manner in brachial
plexus lesions but not in amputation and stroke

23. Hemineglect
An Interesting Case from
Prof.A.V.Srinivasan’s
Unit

24. Can the mind believe
what the eye sees ?
On vision, visuospatial
dysfunction and body image
perception in right hemispherical
dysfunction
Dr.K.Bijoy Menon (Senior Resident)
Dr.Sundar, Dr.Saravanan, Dr.Ramakrishnan
Dr.Nithyanandan (Asst.Prof) ,
Prof. A.V.Srinivasan

25. We thank
 Prof.V.S.Ramachandran , M.D.,
Ph.D., Director
Centre for Brain and Cognitive Sciences
University of California, San Diego, USA

26. Indrani. 50 year old female
 Presents with sudden onset of weakness
of left upper and lower limb
 O/E.
Conscious, oriented to time, place and person
Mild left UMN facial paresis
Left hemiplegia
All peripheral pulses palpable

27.  CT Brain – P – Shows a (R) Occipitotemporal
infarct

28. Higher mental function evaluation
 MMSE : 28/30
 She was very attentive and quite clear in her
conversation with us, though she would be
complaining of a vague left sided shoulder pain
On lobar testing, she had
 Left visual neglect with (L) hemianopia
 No auditory neglect
 Absent sensory perception in (L) upper limb and
(L) tactile neglect in the lower limb

31. On cold caloric tests and its effect
on neglect

32. Video of Neglect

33. Video of caloric test and Nystagmus

34. Video of disappearance of neglect

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

36. After caloric test, Mirror Agnosia on the Left

37. ‘Mirror Agnosia’ to front

38.  On Anosognosia, Body neglect
(Hemisomatognosia) and
somatoparaphrenia
 Anosognosia – our patient has it
 Body neglect by Bisiach’s test – our patient
does not have it
 Somatoparaphrenia – our patient has it

39. Somatoparaphrenia

40. On the somatophrenic arm and mirrors

41.  On Allesthesia, tactile neglect and ‘blind touch’
 ‘Touch your left arm’ Bisiach’s test of body
neglect.
 Absent proprioception and touch in the left upper
limb
 Patient is still able to touch her left arm whatever
position the examiner keeps the arm in.

42. Blind Sight Vs Blind Touch

43.  On visual imagery, neglect and caloric tests
 Visual imagery
 Bisiach’s test
 Our test

44. Results

45. Unconscious awareness in a person with
Blind Sight
And
Blind Touch
Conscious mind and unconscious mind
Theories of consciousness and the soul.

46. My sincere gratitude to my
Teachers, Patients and
Madras Institute of Neurology,
MEDISCAN SYSTEMS & Mr.Thudhimugan
for their computer work

47. Dedicated to my family for
making everything worthwhile

48. READ not to contradict or confute
Nor to Believe and Take for Granted
THANK
but TO WEIGH AND CONSIDER
YOU