Unconscious Sensory Perception in a Case of Hemineglect

Authors:

Ramachandran S. VilayanurSrinivasan V. Avathvadi

Bijoy K. Menon, Nithyanandam V. Allimuthu, Diane R. Rogers

Monday, October 9, 2006 Poster Session II

M65

Objective and Background

To describe dissociation between various tests of personal neglect and to demonstrate unconscious sensory perception.

Personal neglect is tested by Bisiachs test or by tests of attention to the left half of body. Normally these tests are congruent

Case vignette 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 paresisLeft hemiplegiaAll peripheral pulses palpable

Designs/Methods

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

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

Designs/Methods

Our patient had (L) hemiplegia, (L) somatosensory loss with (R) temperooccipital infarct. Neuropsychological evaluation revealed the following.

On cold caloric tests and its effect on neglect

Video of Neglect

Video of caloric test and Nystagmus

Video of disappearance of neglect

On ‘ Mirror Agnosia’Mirror Agnosia on the Right

After caloric test, Mirror Agnosia on the Left

‘Mirror Agnosia’ to front

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

Somatoparaphrenia

On the somatophrenic arm and mirrors

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.

Blind Sight Vs Blind Touch

On visual imagery, neglect and caloric

tests

Visual imagery

Bisiach’s test

Our test

Results

Results

Our patient had personal neglect on tests of attention to the left half of her body with anosognosia grade I and severe somatophrenia of her left arm. Intriguingly, when asked to point to her left eye she grasped her left hand with her intact right arm and used it to touch her eye showing tacit knowledge of paralysis despite anosognosia and somatophrenia.

Results Cont..

We show unconscious sensory perception in a patient with sensory loss, somatophrenia and neglect. This is a new phenomenon similar to blind sight.

Neglect – Cognitive inability to response to contralesional stimulus – Robertson and Marshall

Blindsight – Weiskrant et al., 1974– Interesting question is: if the parients can ‘see’ the stimulus

enough to point to it, why aren’t they consciously aware of it?

Patient with Unilateral neglect – Unilateral neglect is, in a sense, the opposite side of this

coin. – A patient with neglect fails to respond and report objects

and stimuli presented in the region opposite to the lesion site, but has an otherwise intact visual field.

Discussion

Discussion cont..

By showing unconscious sensory

perception in a patient with sensory loss,

somatophrenia and neglect, we suggest

that this is a new phenomenon similar to

blind sight and raises questions about

unconscious sensory perception.

Unconscious awareness in a person with

Blind Sight

And

Blind Touch

Conscious mind and unconscious mind

Theories of consciousness and the soul.

Conclusion

We show unconscious sensory perception in a patient with sensory loss, somatophrenia and neglect. This is a new phenomenon similar to blind sight and raises questions about unconscious sensory perception.