Cortical Localisation

Frontal Lobe

•    Functions: executive function, motivation, personality, motor planning (primary motor cortex).

•    Lesions:

o    Disinhibition, apathy.

o    Broca’s aphasia (dominant hemisphere): non-fluent, intact comprehension.

Parietal Lobe

•    Functions: sensory integration, visuospatial processing.

•    Dominant hemisphere (usually left):

o    Gerstmann syndrome: agraphia, acalculia, finger agnosia, left-right disorientation.

•    Non-dominant hemisphere:

o    Hemispatial neglect.

Temporal Lobe

•    Functions: memory (hippocampus), auditory processing.

•    Lesions:

o    Wernicke’s aphasia (fluent but nonsensical speech, poor comprehension).

o    Visual field defect: superior quadrantanopia (“pie in the sky”).

Occipital Lobe

•    Functions: visual processing.

•    Lesions:

o    Homonymous hemianopia with macular sparing.

o    Anton syndrome: cortical blindness with denial of visual loss.

Dementia Syndromes

•    Alzheimer’s Disease

o    Early episodic memory impairment.

o    MRI: medial temporal (hippocampal) atrophy.

o    Biomarkers: ↓ CSF Aβ42, ↑ tau.

•    Vascular Dementia

o    Stepwise decline.

o    Focal signs (e.g., hemiparesis).

o    Strategic infarcts.

•    Dementia with Lewy Bodies

o    Fluctuating cognition, detailed visual hallucinations.

o    Parkinsonism.

o    Neuroleptic sensitivity.

•    Frontotemporal Dementia

o    Early personality and behavioural change (disinhibition, apathy).

o    Language variants (primary progressive aphasia).

Epilepsy

•    Focal: often preceded by aura; can become generalised.

•    Generalised: absence (3 Hz spike-and-wave), tonic-clonic, myoclonic.

First Seizure Work-up

•    Blood glucose, electrolytes, calcium, renal and liver function.

•    MRI brain (structural lesion exclusion).

•    EEG (supportive, not diagnostic alone).

Drug Choices

•    Valproate: broad-spectrum; avoid in women of childbearing potential (teratogenicity, PCOS risk).

•    Lamotrigine: preferred in young women.

•    Levetiracetam: fewer interactions; can cause mood disturbance.

Multiple Sclerosis (MS)

Features

•    Optic neuritis (painful visual loss, RAPD).

•    INO: impaired adduction, abducting nystagmus.

•    Sensory level, Lhermitte’s sign.

Diagnosis

•    MRI: T2/FLAIR hyperintense periventricular lesions ("Dawson fingers").

•    CSF: oligoclonal bands (intrathecal IgG synthesis).

Treatment

•    Acute relapse: IV methylprednisolone.

•    Long-term disease modification: interferon-beta, glatiramer acetate, natalizumab, fingolimod.

Autoimmune Encephalitis

•    Features: subacute onset memory deficits, psychiatric symptoms, seizures, dyskinesias.

•    Anti-NMDA receptor encephalitis:

o    Common in young women, ovarian teratoma association.

•    Investigations: MRI (medial temporal hyperintensities), CSF (pleocytosis, oligoclonal bands), EEG (slow waves).

Extra Revision Pearls

•    Pie in the sky defect clue → temporal lobe lesion

•    Gerstmann syndrome clue → dominant parietal lobe lesion

•    Hemineglect clue → non-dominant parietal lobe

•    Fluctuating cognition + hallucinations clue → Lewy body dementia

•    Painful visual loss clue → optic neuritis (MS)

•    Young woman with psychosis + ovarian mass clue → NMDA receptor encephalitis