Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Part I Basic aspects of neurodegeneration
- Part II Neuroimaging in neurodegeneration
- Part III Therapeutic approaches in neurodegeneration
- Normal aging
- Part IV Alzheimer's disease
- Part VI Other Dementias
- Part VII Parkinson's and related movement disorders
- Part VIII Cerebellar degenerations
- 46 Approach to the patient with ataxia
- 47 Autosomal dominant cerebellar ataxia
- 48 Friedreich's ataxia and other autosomal recessive ataxias
- 49 Ataxia telangiectasia
- Part IX Motor neuron diseases
- Part X Other neurodegenerative diseases
- Index
- References
46 - Approach to the patient with ataxia
from Part VIII - Cerebellar degenerations
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- List of contributors
- Preface
- Part I Basic aspects of neurodegeneration
- Part II Neuroimaging in neurodegeneration
- Part III Therapeutic approaches in neurodegeneration
- Normal aging
- Part IV Alzheimer's disease
- Part VI Other Dementias
- Part VII Parkinson's and related movement disorders
- Part VIII Cerebellar degenerations
- 46 Approach to the patient with ataxia
- 47 Autosomal dominant cerebellar ataxia
- 48 Friedreich's ataxia and other autosomal recessive ataxias
- 49 Ataxia telangiectasia
- Part IX Motor neuron diseases
- Part X Other neurodegenerative diseases
- Index
- References
Summary
Definition and classification of ataxia
The term ataxia is derived from ancient Greek and literally means absence of order. In modern clinical neurology, ataxia is used to denote disturbances of coordinated muscle activity. Ataxia is caused by disorders of the cerebellum and its afferent or efferent connections. Spinal afferent pathways are often involved in ataxia disorders. Diseases of the peripheral nervous system, such as chronic idiopathic demyelinating polyneuropathy, may also cause ataxia. However, ataxia is rarely the prominent symptom in these disorders.
The afferent and efferent connections of the cerebellar cortex are topographically organized resulting in functional specialization of different parts of the cerebellum. Dysfunction of the lower vermis (vestibulocerebellum) leads to truncal ataxia. Spinocerebellar lesions (upper vermis and anterior parts of hemispheres) are characterized by unsteadiness of gait and stance which are more evident after eye closure (positive Rombergism). The most prominent symptom of neocerebellar damage (cerebellar hemispheres) is ataxia of intended limb movements. Ataxic limb movements are irregular and jerky and tend to overshoot the target (past-pointing). They are often accompanied by rhythmic side-to-side movements as the target is approached (action or intention tremor). Dysarthria characterized by slow and segmented speech with variable intonation and disturbances of ocular movements (broken-up smooth pursuit, saccadic hypermetria, gaze-evoked nystagmus) almost invariably accompany ataxia of gait and limb movements (Diener & Dichgans, 1992; Thach et al., 1992).
Knowledge of the topographical organization of the cerebellum is helpful for the localisation of focal cerebellar disease.
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- Neurodegenerative DiseasesNeurobiology, Pathogenesis and Therapeutics, pp. 699 - 708Publisher: Cambridge University PressPrint publication year: 2005