From the Guidelines
Cerebellar disorders are typically associated with scanning dysarthria and ataxic dysarthria, which can be effectively managed with speech therapy focusing on rate control, breathing techniques, and articulatory precision, as recommended by recent guidelines 1. The most characteristic type of speech abnormality in cerebellar disorders is scanning dysarthria, featuring slurred articulation, irregular rhythm, and a tendency to separate syllables in a halting, explosive manner. Ataxic dysarthria is another common manifestation, characterized by irregular timing of speech movements and imprecise consonant pronunciation. These speech disturbances occur because the cerebellum plays a crucial role in coordinating the timing and execution of complex motor sequences required for fluent speech, as highlighted in a guideline for healthcare professionals from the American Heart Association/American Stroke Association 1. Some key features of cerebellar speech disorders include:
- Impaired control of speech volume, resulting in abnormally loud or soft speech
- Hypotonia of speech muscles, leading to breathy voice quality
- Cerebellar tremor, causing rhythmic interruptions in phonation
- Irregular timing of speech movements and imprecise consonant pronunciation According to a recent review of cases of self-reported foreign accent syndrome (FAS), some cases may be the result of a functional neurological disorder (FND), which can be identified by internally inconsistent changes in articulation and prosody 1. Treatment strategies for cerebellar speech disorders may include:
- Education and explanatory approaches to reassure patients and explain the nature of their symptoms
- Symptomatic approaches to reduce excessive musculoskeletal tension and eliminate secondary or accessory movements
- Psychological approaches to address psychosocial issues and cognitive features related to locus of control and executive function
- Medical approaches to provide information and advice on reducing acid reflux and signposting for appropriate medical management of acid reflux and/or post-nasal drip, as recommended in the Journal of Neurology, Neurosurgery and Psychiatry 1.
From the Research
Types of Speech in Cerebellar Disorders
- Cerebellar disorders can lead to various types of speech disturbances, including dysarthria, which is a motor speech disorder characterized by difficulties in speech quality and intelligibility 2.
- There are six major types of dysarthria, including ataxic dysarthria, which is primarily caused by cerebellar dysfunction, and is characterized by alterations in the normal timing pattern of speech, with prolongation of segments and a tendency toward equalized syllable durations 3.
- Ataxic dysarthria is also associated with disturbances of syllable timing, abnormal contours of fundamental frequency, and dysprosodic aspects, such as monotone and syllable-falling patterns 3.
- The areas of cerebellar damage most commonly associated with dysarthria are the superior portion of the left cerebellar hemisphere, with damage to this area leading to slowing down of articulatory movements, increased variability of pitch and loudness, monotonous and "scanning" speech, and articulatory impreciseness 4, 5.
Characteristics of Cerebellar Dysarthria
- Cerebellar dysarthria is characterized by a range of speech disturbances, including:
- The paramedian regions of the superior cerebellar hemispheres are relevant for the development of cerebellar dysarthria, with damage to these areas leading to the characteristic speech disturbances 5.
Cerebellar Function in Speech and Language
- The cerebellum plays a role in regulating motor movements, including those involved in speech production, and damage to the cerebellum can lead to dysarthria and other speech disturbances 2, 6.
- The cerebellum may also be involved in language production, with studies suggesting that it can contribute to cognition and language, particularly in the areas of language processing and production 6.