AV Srinivasan
The Tamil Nadu Dr. M.G.R Medical University, India
Keynote: J Neuro Neurophy
VS Ramachandran and AV Srinivasan et al (1998) described allesthesia and extinction of referred sensations in
brachial plus lesions. K. Sathian et al (2000) suggested that intermanual referral of sensations can occur after
central lesions of the Somato sensory system. This communication considers eight patients with five central lesions
and three peripheral lesions of the Somato sensory system.
Methodology & Theoretical Orientation: Ecological
model of sensory modulations has external and internal dimensions. This refers both physiological and behavioural
responses. Disfunction in sensory integration is the ability, modulate, discriminate, co-ordinate or organise
sensation adaptively. Eight patients aged between 19-51 with brachial plexus lesion one, amputation 2 patients,
hemiparesis with hemisensory deficit five patients were analysed. Patients vibration and kinesthesis were tested.
Stimuli were applied manually. All patients had Magnetic Resonance Imaging of the Brain and ENMG studies.
Findings: Central lesions: All the five stroke patients showed intermanual referral of sensations between 3rd and
4th month after developing hemisensory deficit. Three had thalamic stroke and two patients has temparoparietal
infarct. Intermanual referred sensations to the affected hand in these patients were not referred to the affected
leg. Intermanual referred sensations were poorly localised and the facial sensations were referred with increased
intensity in the thalamic patients. When applied pressure on the normal hand resulted in the extinction of pain
sensation side and pain recurred within one minute of the pressure being relieved. Peripheral Lesions: Amputation
of Limbs: Both the patients (below elbow and knee amputation) showed intermanual referral sensation within
ten days. The referred sensation of touch and vibration lacked spatial organisation and poor localization with a
relatively high threshold. Brachial Plexus Lesion: Patient had sensation intermanually referred in a topographically
organised manner in the phantom limb. Intriguingly, simultaneous stimulation of the specific region (e.g. thumb)
of the face and the corresponding finger of the right hand resulted in a mutual cancellation or extinction of the
referred sensations in the phantom limb.
Conclusions & Significance: 1.0 Intermanual referral of the sensations in
the phantom limb occurred immediately in Brachial plexus lesion and amputation, whereas it occurred after a delay
of three month is in hemiparesis with hemisensory deficit. This can be utilised for extinction of pain in the paretic
side and in the Phantom limb. 2.0 Sensations were referred intermanually in a topographically organized manner in
Brachial Plexus lesions, whereas in amputations and hemiparesis with hemisensory deficit, lacked spatial and poor
localization. Disclosure: Dr. Venkatesan has nothing to disclose.
Recent Publications:
1. Willis WD Jr.: The sensory
system with emphasis on structures important for pain. Brain Res Rev 2007; 55:297-313.
2. Miller LJ, Reisman JE. An
ecological model of sensory modulation, Chapter 4,292-324.
3.DOBKIN BH. The clinical science of neurological
rehabilitation. Second edn, Chapter 4, 292-324.
4. Srinivasan AV, Ramachandran VS, Ramachandran R,et al,
127th Annual Meeting of the AMRICAN Neurological Association; Oct 12 to 16,2002. Marriot Marquis Hotel, New
York.
5. Srinivasan AV, Velmurugendran CU, Roger-Ramachandran, et al,. Anaesthesia and extinction of referred sensations after brachial plexus avulsion 5th American Academy of Neurology Meeting: Minneapolis.1998.
6.
RamachandranVS, Hirstein W. T he perception of phantom limbs: the DO.Hebb lecture. Brain. 1998:121:1603-30
He is Emeritus Professor in the Tamil Nadu Dr. M.G.R. Medical University; Former Adjunct Prof.–IIT (Madras) – (Bio – Technology) and Visiting Professor in Cleveland –Ohio – USA; Hershey Medical College, USA and Former Adjunct Prof. –IIT (Madras) –(Bio– Technology)
E-mail: avsekhar1950@gmail.com
