This document provides information on distinguishing features of different types of weakness based on neurological examination findings. It describes patterns of tone, reflexes, muscle distribution and other findings that help localize the lesion and determine if it is upper motor neuron, lower motor neuron, extrapyramidal, brainstem, bulbar, pseudobulbar, cerebellar, spinal cord or neuromuscular junction related. Specific diseases are given as examples for each category.

1. Tone Reflexes Plantars Muscles Distribution Other
Increased
(clasp knife spasticity) Increased Up
* Contralateral to lesion
* According to territory * Clonus
Decreased Decreased Down Wasting
* Ipsilateral
* Myotome or named nerve
distribution
* Fasciculations
Increased
(rigidity, cogwheeling if
+ tremor)
* Bradykinesia or hyperkinesia
* +/- Tremor
* Cranial nerve lesion on
ipsilateral side
* Hemiplegia on contralateral
side
* Ataxia
* Nystagmus
* INOP
* Vertigo
* Dysarthria
Decreased Decreased
wasted (e.g.
tongue)
* Cranial nerves IX-XII in the
medulla * Hoarse voice
MND, GBS,
Polio, MG,
syringobulbia,
brainstem
tumours, central
pontine
myelinolysis
Increased Increased, including palatal
reflexes
* UMN lesion of muscles of
swallowing and talking due to
bilateral lesions above the mid
pons.
* slow tongue movements
* slow deliberate speech
* pseudobulbar affect: unprovoked
weeping or giggling "emotional
incontinence"
MS, MND,
stroke, central
pontine
myelinolysis
Hypotonia Hyporeflexia
* Eyes
* Arms
* Legs
* Trunk
* Ipsilateral or bilateral
* Dysdiadochokinesia
* Ataxia
* Nystagmus
* Intention tremor, Dysmetria
* Staccato/slurred speech
Tone reduced in acute
cord compression
Hyperreflexia below level of
lesion, hyporeflexia at level
of lesion, normal above
level of lesion. In acute
lesion reflexes decreased.
* Motor and sensory symptoms
with sensory level, LMN lesion
at level and UMN lesion below
level
Myasthenia gravis Normal
* Extraocular
* Bulbar
* Face
* Neck
* Limb
* Trunk
* FATIGUABILITY
also: botulinum
toxin!
Lambert Eaton
myasthenic syndrome Hyporeflexia
* Gait before eyes
* Autononic (dry mouth) * Movements improve symptoms
Muscular dystrophy Preserved
Duchenne's:
pseudohypetrop
hy of calves
* Symmetrical PROXIMAL
weakness: can't get out of chair
or comb hair
* Across distributions
* +/- Respiratory / cardiac
symptoms
* Gower's sign
* Gradual onset
* Oddly firm muscles
Duchenne vs
Becker's vs
drug vs
inflammatory
inclusion body
myositis
Myotonic dystrophy Wasting
* DISTAL weakness
* Facial weakness
* +/- Respiratory / cardiac
* Myotonia (prolongued muscle
contractions)
Metabolic/ischaemic
myopathy
* Pain after / on exercise
What could mimic weakness: reduced proprioception, pain, reduced sensation in hands (e.g. carpal tunnel syndrome)
Differentiating Features of Weakness
Type of Lesion
Properties
UMN
LMN
Extrapyramidal
Brainstem
Bulbar
Pseudobulbar
Cerebellar
Cord Lesion
NMJ lesion
Myopathy

2. * Symmetrical PROXIMAL
* +/- Dysphagia
* +/- Dysphonia
* +/- Respiratory weakness
* Striated muscle only
* Progressive
* + Myalgia (spontaneous pain at rest)
* Can be paraneoplastic: skin rashes,
fever, arthralgia, Raynaud's
* +/- Evidence of systemic disease, or
pulmonary fibrosis, myocarditis, fever,
Raynaud's
* DERMATOMYOSITIS = myositis + skin
signs, e.g. heliotrope, macular rash,
Gottron's papules, ...
Areflexia * DISTAL weakness (or
ascending as in GBS)
* + Paraesthesiae
* + Autonomic
* Rapid onset
* +/- pain (inflammation)
Myositis = inflammatory
myopathy
Neuropathy
Multifocal motor neuropathy with
conduction block
Named nerve palsy