--- module: 031-02 language: en chapter: 31 title: "Neurological History, Examination, Localisation, and Investigations" module_title: "Bedside localisation, examination reliability, and test selection" source_sha256: b932fdbaa1e98050578cb5284dc89306d1e7ca3d343afc487f39544d6957e54d --- # Bedside localisation and test selection ## Narrative to anatomical model ### Summary: failed function, distribution, onset #### More localising than a diagnostic label ### Identify instability first #### Airway, respiratory weakness, status, cord compression #### Changes order and speed of assessment ## History and episodes ### History may localise better than hurried exam ### Positive phenomena: excess or spreading activity ### Negative phenomena: loss of function #### Distinction helpful but not absolute ### Migraine aura spreads over minutes ### Embolic ischaemia starts abruptly ### Presyncope: warmth, sweating, recovery supine ### Convulsive movements can occur in syncope ### Confusion, tongue injury, rhythmic activity: seizure ## Reliability and mental status ### Ensure hearing, vision, language, wakefulness ### Record pain, fear, sedation, effort limits ### Repeat after repositioning or distraction ### Serial examination reveals change ### Orientation relatively insensitive ### Attention before delayed recall ### Cues and recognition: retrieval versus encoding ## Vision and eye movements ### Monocular loss: anterior to chiasm ### Bitemporal loss: chiasm ### Homonymous defect: contralateral retrochiasmal ### Red desaturation and afferent pupillary defect ### Anisocoria in light and dark identifies pathway ### Binocular diplopia means misalignment ### Third nerve with pupil: compression concern ### Sixth nerve may be non-localising ### Internuclear ophthalmoplegia: medial fasciculus ## Face, bulbar, and ventilation ### Forehead sparing not infallible ### Taste, tears, hyperacusis refine facial level ### Wet voice, weak cough, drooling: aspiration risk ### Tongue wasting, fasciculation: LMN ### Spastic tongue, brisk jaw: corticobulbar ### Ventilatory failure without breathlessness #### Saturation normal until CO2 retention advanced #### Measure forced vital capacity serially ## Motor and reflexes ### Pronator drift detects subtle pyramidal weakness ### Position joint, stabilise, then grade ### Proximal symmetric weakness: muscle, many mimics ### Fatigable ptosis, diplopia: junction failure ### Reflexes read as a pattern #### Asymmetry beats absolute briskness #### Absent ankle with distal loss: neuropathy ### Acute cord injury may be flaccid first ### Brisk jaw with limb UMN: above cervical cord ## Sensory testing ### Answer an anatomical question ### Move from normal toward abnormal ### Pinprick small fibre, vibration dorsal column ### Sensory level may lie below lesion #### Check from both directions ### Irregular stimuli, non-leading choices ### Reproducible boundary over single error ## Gait ### Hemiparetic circumduction, spastic scissoring ### Foot drop: high-stepping gait ### Cerebellar broad base, sensory ataxia without vision ### Parkinsonism: short stride, poor turning ### Frontal: initiation failure despite strength ## Localisation and negative findings ### Built from concordant findings ### Plexus spans nerves, not length-dependent ### Mononeuropathy may need electrodiagnosis ### Normal early reflexes or imaging do not exclude ### Consider multiple lesions or systemic process ## Investigations and synthesis ### Diffusion detects acute infarction ### Imaging causal only when anatomy aligns ### Choose CSF tests before the puncture ### Do not delay antimicrobials ### Prolonged EEG raises yield ### Early electromyography may miss denervation ### State best localisation and dangerous alternatives ### Record conditions so others can compare