Neurological Localization Part II Where is the lesion

Neurological Localization (Part II) 神經內科 洪國華

Where is the lesion? 1. 2. 3. 4. 5. 6. 7. 8. Brain Cerebellum Brainstem Spinal cord Root Peripheral nerve Neuromuscular junction Muscle

Where is the lesion? 1. 2. 3. 4. 5. 6. 7. 8. Brain – Cortical dysfunction & visual field cut Cerebellum – Clumsiness & action tremor Brainstem – Cranial nerve (5 Ds) & crossed signs Spinal cord – Triad (sensory level + spastic paraplegia + incontinence) Root – Pain + asymmetric weakness with sensory change Peripheral nerve – Symmetric/asymmetric distal weakness with sensory change NMJ – Fluctuating muscle weakness Muscle – Symmetric proximal weakness

Prototypical Figure

Myopathies Symmetric proximal weakness without sensory deficit

Myasthenia Gravis Muscle weakness with fatigue phenomenon

Sensorimotor Polyneuropathy Symmetric distal weakness with sensory deficit

Entrapment Neuropathy

Cervical Radiculopathy Root pain + Features of peripheral neuropathy

Central Vs Peripheral Nervous System DTR Muscle Tone Atrophy Fascicu- Babinski lation sign CNS lesions (UMN) (even clonus) Disuse atrophy - + PNS lesions (LMN) ↓or absent ↓or normal ++ + - UMN = Upper motor neuron signs LMN = Lower motor neuron signs

• 上運動神經元 = = = Upper motor neuron Corticospinal tract 皮質脊髓徑 • 下運動神經元 = Lower motor neuron = Anterior horn cell = 前角細胞 注意交叉處

Higher Cortical Sensation • • • Stereognosia Nosognosia Barognosia Graphesthesia Two-point discrimation Double simultaneous stimulation

Spinal Cord Posterior column Corticospinal tract Spinothalamic tract Anterior horn cell

Upper Cervical Cord Lesion Triad: Sensory level + Incontinence + Quadriplegia

Lower Cervical Cord Lesion Triad: Sensory level + Incontinence + Quadriplegia

Thoracic Cord Lesion Triad: Sensory level + Incontinence + Paraplegia

Lumbar Cord Lesion Triad: Sensory level + Incontinence + Paraplegia

Brown-Séquard Syndrome Sensory dissociation could be found in cord or brainstem lesion.

Major Long Tracts

Brainstem Lesion 5”D”s + Crossed sign Dysconjugate Eyeballs + Long Tract Signs

Symptoms of Cranial Nerve Damage III IV V VI VIII IX X XI XII Diplopia Decreased facial sensation Diplopia Decreased strength & drooping of face Deafness & dizziness Dysarthria & dysphagia Decreased strength in neck & shoulders Dysarthria & dysphagia 5 “D”s of brainstem lesion: Diplopia, Dizziness, Dysarthria, Dysphagia, Drop attacks

Cerebellar Lesion • • • Hypotonia Asynergia Nystagmus Dysarthria Station and gait disorder Tremor HANDS Tremor

Unilateral Hemispheric Lesion Contralateral facial and hemi-paresis +/- Visual field defect +/- Cortical dysfunction +/- Seizure

Subcortical Lesion of Right Temporal Lobe Lesion in Meyer’s Loop

Cerebral Cortex

Primary somatosensory area Primary motor area

Where is the lesion? 1. 2. 3. 4. 5. 6. 7. 8. Brain – Contralateral facial and limb weakness +/Cortical dysfunction +/- visual field defect Cerebellum – HANDS Tremor Brainstem – Cranial nerve (5 Ds +/- dysconjugate eyeballs) & crossed signs Spinal cord – Triad (sensory level + spastic paraplegia + incontinence) Root – Radicular pain + features of peripheral neuropathy Peripheral nerve – Symmetric/asymmetric distal weakness with atrophy and sensory change NMJ – Fluctuating muscle weakness Muscle – Symmetric proximal weakness

Pure Hemiparesis • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Hemiparesis with Additional Deficits • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Hemiparesis Sparing the Face • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Unilateral Face & Arm Weakness • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Brachial Monoparesis • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Crural Monoparesis • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Facial Weakness (Peripheral Type) • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Facial Weakness (Central Type) • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Brachial Diparesis • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Paraplegia • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Quadriparesis • • Brain Cerebellum Brainstem Spinal cord Root Nerve NMJ Muscle

Where is the lesion? 1. 2. 3. 4. 5. 6. 7. 8. Brain Cerebellum Brainstem Spinal cord Root Peripheral nerve Neuromuscular junction Muscle