Cerebellar degeneration is a general term that describes neuronal cell death in the cerebellum. Damage of the neurons in the cerebellum can be the result of a brain-specific disease or other conditions affecting the body in general.
Examples of brain-related diseases leading to cerebellar degeneration include spinocerebellar ataxias (SCAs), such as Friedreich’s ataxia, or multiple system atrophy (MSA). On the other hand systemic conditions such as chronic alcohol abuse or malignancies misleading the immune system to attack neurons in the cerebellum (paraneoplastic cerebellar degeneration) have also been identified as causes of cerebellar degeneration.
Signs and Symptoms
Common symptoms of cerebellar degeneration include ocular motor disorders, imbalance and loss of coordination with limb and gait ataxia, which can make diagnosis difficult, since these symptoms are also found in association with other neurodegenerative diseases.
Ocular motor disorders observed in connection with cerebellar degeneration include several forms of nystagmus, such gaze-evoked nystagmus, downbeat nystagmus or rebound nystagmus.
The diagnosis of cerebellar degeneration varies, depending on the suspected associated condition but should include an ocular motor examination and MRI-scan.
Observable ocular motor disorders
- Downbeat nystagmus
- Rebound nystagmus
- Gaze-evoked nystagmus in all directions
- Saccadic smooth pursuit
- Impaired visual fixation suppression of the vestibulo-ocular reflex (VOR)
- Hypometric saccades
- Hypermetric saccades
- Central positional nystagmus
- Period alternating nystagmus
0.15 When the patient looks to the right, there is a gaze-evoked nystagmus to the right. When the patient looks to the left there is a gaze-evoked nystagmus to the left. 0.24 When the patient looks upward there is a slight upwardly-beating nystagmus. 1.00 Smooth pursuit is saccadic horizontally 1.19 and vertically. 1.37 Testing of the saccades: not significantly impaired. 2.00 Optokinetic nystagmus: is reduced, indicating a smooth pursuit deficit in this patient. 3.00 Visual fixation suppression of the VOR is only slightly impaired because the patient has a bilaterally pathological head-impulse test. 3.25 This means that visual fixation suppression of the VOR cannot be properly examined in these patients with a combination of cerebellar oculomotor disorders and a high-frequency deficit of the VOR. Diagnosis: cerebellar ataxia and vestibular areflexia syndrome.
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