Differential Diagnosis   of   Common Signs in Neurology   upper motor neurone signs  cerebellar signs

In the clinical examination, the neurological examination usually centres around the upper and the lower limbs. The commonest physical signs are upper motor neurone lesions and cerebellar signs mainly because these are commonly associated with ocular signs, for example visual field defect in upper motor neurone lesions and ocular motility disorders in the cerebellar lesions.

Upper motor neurone lesions
(The signs are:

• upper arm drift
• characteristic posture ie. the flexors in the upper limb is stronger than the extensor resulting in     shoulder adduction, elbow flexion, wrist flexion and fingers flexion. In the lower limb, the extensors are stronger resulting in extension and adduction of the hip, dorsiextension and inversion of the ankle.
• hypertonia
• hyper-reflexia
• positive Babinski's response

Congenital

• cerebral palsy

• cerebrovascular accident which may be ischaemic or haemorrhagic
• demyelination ie. multiple sclerosis
• tumours both primary and secondary
• migraine
• infectious from brain abscess
• trauma

Cerebellar signs
(The most likely cause in the examination is multiple sclerosis. The signs are best remembered with the mnemonic HANDS Tremors

• Hypotonia
• Asynergy ie lack of co-ordination with disdianochokinesia
• Nystagmus
• Dysarthria ie. both scanning and explosive speech
• Stance and gait ie. postural instability and broad base gait
• Tremor ie. intentional tremor)

• cerebral palsy
• developmental abnormality (Chiari malformation or cerebral aplasia)
• hereditary such as Friedriech's ataxia

• demyelination as in multiple sclerosis
• vascular as in infarction, haemorrhage, vascular malformation or vasculitis
• neoplasm which may be primary (astrocytoma and haemangioblastoma) or secondary
• infection (viral encephalitis, TB)
• metabolic disorders (thiamine deficiency, hypothyroidism)
• drugs and toxins (phenytoin, barbiturates, alcoholism,  lead poisoning )
• paraneoplastic (cerebellar degeneration may be associated with lung or breast carcinoma)
• trauma