About the Basal Ganglia
- The Basal Ganglia give rise to the extrapyramidal tract, which modulates the corticospinal (pyramidal) tract.
- This tract controls muscle tone, regulates motor activity, and generates postural reflexes
- However, the extrapyramidal tract’s efferent fibers communicate via the cerebral cortex and thalamus – they do NOT communicate directly with the spinal cord
Lesions to the Basal Ganglia
- When damage is restricted to extrapyramidal tract, patients have NO paresis or neuropsychological impairments
- Characteristic features of basal ganglia (i.e., extrapyramidal) injury involve the following involuntary movement disorders:
- Parkinsonism – combination of resting tremor, rigidity, bradykinesia/akinesia, and postural abnormalities
- Athetosis – slow continuous, writhing movements of the fingers, hands, face, and throat
- Chorea – intermittent jerking of limbs and trunk
- Hemiballismus – intermittent flinging of the arm and leg on one side of the body
Lewy Body Disease
- Possibly accounts for up to 30% of cases diagnosed as Alzheimer’s Disease
- May be a variant of Alzheimer’s rather than a distinct illness
- Unlike Alzheimer’s, it has a relatively rapid development of dementia
- It is accompanied by mild extrapyramidal features such as:
- Masked face
- Bradykinesia
- Resting tremor
- Gait impairment pronounced enough to lead to falls
- Can also present with depression, delusions, and visual hallucinations
Definitive diagnosis confirmed with an abundant presence and unusual location of Lewy Bodies distributed diffusely throughout the cerebral cortex