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Prof. A.V. SRINIVASAN.

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.

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Prof. A.V. SRINIVASAN.

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  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 Institute of Neurology Chennai Chennai Sensory Stimulation in Neurological Rehabilitation

  2. NEU CON NeuConCONTROVERSIES IN NEUROLOGYAPRIL 3-4, 2010G.ARJUNDAS

  3. SHRI US MEHTA ORATION

  4. Basic Principles Thomas Elbert • 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.

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

  6. 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

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

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

  9. 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)

  10. 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

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

  12. 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

  13. 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

  14. 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

  15. INTERMANUAL REFERAL AND EXTINCTION OF PAIN SENSATION

  16. 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

  17. 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

  18. 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).

  19. 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

  20. Hemineglect An Interesting Case fromProf.A.V.Srinivasan’s Unit

  21. 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

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

  23. 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

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

  25. 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

  26. On cold caloric tests and its effect on neglect

  27. Video of Neglect

  28. Video of caloric test and Nystagmus

  29. Video of disappearance of neglect

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

  31. After caloric test, Mirror Agnosia on the Left

  32. ‘Mirror Agnosia’ to front

  33. 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

  34. Somatoparaphrenia

  35. On the somatophrenic arm and mirrors

  36. 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.

  37. Blind Sight Vs Blind Touch

  38. On visual imagery, neglect and caloric tests • Visual imagery • Bisiach’s test • Our test

  39. Results

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

  41. Thank You

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