This document discusses false localizing signs in neurology. False localizing signs are neurological signs that indicate dysfunction in a location distant from the actual site of pathology. The document provides several examples of false localizing signs involving the cranial nerves, motor system, cerebellum, and other areas. It also discusses the potential pathophysiological mechanisms and includes historical cases demonstrating false localizing signs.

1. FALSE LOCALISING SIGNS.
Chairperson: Dr.Seetaram.N.K
Student: Dr.Varun.

2. Neurological signs have been described as ‘false
localizing’ if they reflect dysfunction distant or
remote from the expected anatomical locus of
pathology and hence challenging the traditional
clinicoanatomical correlation paradigm.
Jobin v joseph, False Localising Signs in Neurology, Indian Journal of Clinical Practice, Vol. 23, No. 9
February 2013

3. William Macewen.
Scottish neurosurgeon.
1876- Frontal lobe abscess.
1879- Left frontal meningioma.

4. BRAIN
1904

5. 8 year child
Headache, vomitting
Left cerebellar symptoms
Lesion?
SEIZURES (Left focal)
LOCALISATION

6. • Supratentorial- 13 %
• Infratentorial- 4%
Tumours of the cerebellum rarely fail to
show the signs of cerebellar involvement.
• Paralyses of cranial nerves. 10 %
• Hemianopia.
• Jacksonian epilepsy.
• Bilateral spastic paresis.
• Cerebellar signs.

7. False localising signs.
Cranial nerve.
1) 6th nerve.
Most common
Seen in both supra and infra tentorial
lesions.
Reason: compression against the petrous
ligament or the ridge of the petrous
temporal bone.

10. 2) Oculomotor nerve : Unilateral fixed dilated
pupil (Hutchinson’s pupil)
May occur with an ipsilateral lesion such as an
intracerebral hemorrhage,
Reason:due to transtentorial herniation of the
brain compressing the oculomotor nerve against
the free edge of the tentorium.

14. • Because of the fascicular organization of the
fibers within the oculomotor nerve, the
externally placed pupillomotor fibers are most
vulnerable.
• Divisional third nerve palsies may sometimes
occur with more proximal lesions, presumably as
a consequence of the topographic arrangement
of the fascicles within the nerve

15. • 3) Fourth cranial nerve- Involvement can be
sometimes seen in idiopathic intracranial
hypertension.
• Exact mechanism not clear.

17. 4) Fifth cranial nerve: Seen in posterior fossa
tumour, Idiopathic intracranial hypertension.
Pathophysiology: Brain stem distortion resulting
in traction on cranial nerves.
Vascular compression of the nerve root.
Similar involvement of 7th and 8th cranial nerve is
also noted.

18. • Concurrent false-localizing involvement of
multiple cranial nerves has been noted on
occasion with a contralateral acoustic neuroma
and trigeminal, glossopharyngeal and vagus
nerves with a contralateral laterally-placed
posterior fossa meningioma.

19. 6) Papilledema- Variable extension of meninges
around the Optic nerve.
Transmission of pressure onto the nerve reduce
axoplasmic flow resulting in papilledema.

21. MOTOR SYSTEM
• 1)
A supratentorial lesion, such as acute subdural
hematoma, may cause transtentorial herniation
of the temporal lobe, with compression of the
ipsilateral cerebral peduncle against the
tentorial edge; since this is above the pyramidal
decussation, a contralateral hemiparesis results.

22. Kernohan-Woltman notch phenomenon or
Kernohan’s notch syndrome : hemiparesis may
be ipsilateral to the lesion, and hence false-
localizing; this occurs when the contralateral
cerebral peduncle is compressed by the free edge
of the tentorium.

24. • 2) Hemidiaphragmatic paralysis with ipsilateral
brainstem (medullary) compression by an
aberrant vertebral artery has been described, in
the absence of pathology localized to the C3-C5
segments of the spinal cord

25. 3) Lesions at the level of the foramen magnum
may produce, false localising signs: paraesthesia
in the hands and lower motor neurone signs in
the upper limbs. The wasting (“remote
atrophy”), weakness, and areflexia may suggest
the involvement of cervical cord segments well
below the level of the foramen magnum lesion.

26. • Pathophysiology: There is currently no
compelling pathophysiological explanation for
these false localising signs.
• The arterial hypothesis postulates that tumour
in some way compromises descending anterior
spinal artery blood supply to the lower cervical
cord with resultant focal ischaemia.

27. • Low pressure venous system would seem
inherently more vulnerable to the effects of
compression than the arterial system, with
resultant tissue stasis and hypoxia perhaps
causing the clinically observed neurological
dysfunction.
• Mechanical stresses within the spinal cord,
consequent perhaps on the conjunction of
extrinsic compression with the anchoring of the
spinal cord by the dentate ligaments, have also
been suggested to account for remote signs.

28. • 4) Lower cervical cord and upper thoracic cord
lesions:
Compressive cervical myelopathy may produce a
false localising thoracic sensory level in addition
to lower limb weakness and hyperreflexia.

29. • Similarly, lumbar spinal disease may be
simulated by more rostral pathology; for
example, urinary retention, leg weakness, and
lumbar sensory findings may be the presenting
features of high thoracic cord compression, with
clinicoradiological discrepancy of as much as 11
segments.

30. Cerebellar
• Frontocerebellar pathway damage, for example,
as a result of infarction in the territory of the
anterior cerebral artery, may result in
incoordination of the contralateral limbs,
mimicking cerebellar dysfunction.

32. Radiculopathy
• False-localising radiculopathy may occur in the
context of IIH and cerebral venous sinus
thrombosis, manifesting as acral paraesthesias,
backache and radicular pain, and less often with
motor deficits.

33. • Mimic Guillain-Barré syndrome (flaccid-
areflexic quadriplegia).
• The postulated mechanism for such
radiculopathy is mechanical root compression
due to elevated CSF pressure.

34. False hemineglect
• False-localising neglect has been encountered: in
a patient with a posterior fossa meningioma
causing left pontine compression.

35. Pseudosyringomyelia
• Pseudosyringomyelia” has been used to describe
a selective loss of pain and temperature
sensation with relative preservation of vibration
and position sense seen in amyloid
polyneuropathy and Tangier disease, (a small
fibre sensory neuropathy), in the absence of any
spinal cord pathology, and hence false localizing.

36. • Pseudoathetosis.
• Myasthenic nystagmus.
• Subcortical aphasia.
OTHERS

37. Collier’s Prime findings
• Signs appearing late in the course of intracranial
tumour, where general symptoms and signs
preexisted, are often of false portent.

38. • Absence of focal neurological deficits during the
early course of illness is in itself a most
important localizing indicator, confining the
disease to the supratentorial compartment.

39. • As the disease process progress, generalized
symptoms of increased intracranial pressure
may conceal once recognizable true localizing
signs.

40. • Tumours of the cerebellum rarely fail to show
the signs of cerebellar involvement

41. 8 year child
Headache, vomitting
Left cerebellar symptoms
Lesion?
SEIZURES (Left focal)
LOCALISATION

42. 20 year old – headache, vomiting
7 months
Visual disturbance
10 months
left 6th CN palsy
2 months
Left ear complete deafness,
Left facial nerve palsy
3 months
Left cerebellar signs

43. • Glioma in left frontal lobe.

44. References
• James collier, The false localising signs of Intracranial tumour,
Neurology, 1904.
• Companion to clinical neurology, Second edition, William Pryse-
Phillips.
• Clinical neurology, C.David Marsden and Timothy J.Fowler.
• Jobin v joseph, False Localising Signs in Neurology, Indian Journal
of Clinical Practice, Vol. 23, No. 9 February 2013.
• A J Larner, False localising signs, J Neurol Neurosurg Psychiatry
2003;74:415–418.

45. • Dejong’s, The neurological examination, seventh edition.
• Gassel MM. False localizing signs. A review of the concept and
analysis of the occurrence in 250 cases of intracranial meningioma.
Arch Neurol 1961;4:526–54.
• Davis M, Lucatorto M. The false localizing signs of increased
intracranial pressure. J Neurosci Nursing 1992;24:245–50.

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