Brain Lesion
Brain lesions
The following neurological disorders/features may allow localisation of a brain lesion:
Gross anatomy
Parietal lobe lesions
- sensory inattention
- apraxias
- astereognosis (tactile agnosia)
- inferior homonymous quadrantanopia
- Gerstmann's syndrome (lesion of dominant parietal): alexia, acalculia, finger agnosia and right-left disorientation
Occipital lobe lesions
- homonymous hemianopia (with macula sparing)
- cortical blindness
- visual agnosia
Temporal lobe lesion
- Wernicke's aphasia: this area 'forms' the speech before 'sending it' to Brocas area. Lesions result in word substituion, neologisms but speech remains fluent
- superior homonymous quadrantanopia
- auditory agnosia
- prosopagnosia (difficulty recognising faces)
Frontal lobes lesions
- expressive (Broca's) aphasia: located on the posterior aspect of the frontal lobe, in the inferior frontal gyrus. Speech is non-fluent, laboured, and halting
- disinhibition
- perseveration
- anosmia
- inability to generate a list
Cerebellum lesions
- midline lesions: gait and truncal ataxia
- hemisphere lesions: intention tremor, past pointing, dysdiadokinesis, nystagmus
More specific areas
| Area | Associated conditions |
|---|---|
| Medial thalamus and mammillary bodies of the hypothalamus | Wernicke and Korsakoff syndrome |
| Subthalamic nucleus of the basal ganglia | Hemiballism |
| Striatum (caudate nucleus) of the basal ganglia | Huntington chorea |
| Substantia nigra of the basal ganglia | Parkinson's disease |
| Amygdala | Kluver-Bucy syndrome (hypersexuality, hyperorality, hyperphagia, visual agnosia |