Cerebellar Dysarthria (Speech)


Cerebellar dysarthria is a distinct speech disorder that involves muscle weakness explicitly. Dysarthria can adversely affect the intelligibility of speech, the naturalness of speech, or both. As a result, speech may be slow, slurred, and require more effort. Dysarthria differs from aphasia because dysarthria is a motor disorder and aphasia is a language disorder. While there are five types of dysarthria, only two are found in superficial siderosis. Superficial siderosis patients will need to consult with a speech and language specialist.

Diagnosing Dysarthria

Screening for dysarthria is either passed or failed on the initial assessment.

Dysarthria Assessment Goals

American Speech and Language Association (ASHA)

  • describe perceptual characteristics of the individual’s speech and relevant physiologic findings;
  • describe speech subsystems affected (i.e., articulation, phonation, respiration, resonance, and prosody) and the severity of impairment for each;
  • identify other systems and processes that may be affected (e.g., swallowing, language, cognition); and
  • assess the impact of the dysarthria on speech intelligibility and naturalness, communicative efficiency and effectiveness, and participation

Identified Types in Superfical Siderosis

  • Flaccid dysarthria is caused by the dysfunction of cranial nerves and areas in the brain stem and midbrain.
  • Ataxic dysarthria comes from damaged pathways connecting the cerebellum to other areas in the brain.

Flaccid Dysarthria

Flaccid Dysarthria comes from damage to the peripheral nervous system. Speech difficulties are attributed to the dysfunction of the nerves that control the facial muscles, tongue, lips, and throat. It presents as slurring of words or speaking slowly. If nerve palsies are also involved you may also have trouble controlling the muscles in your mouth and face. Patients who exhibit flaccid dysarthria will have difficulties pronouncing consonants.

Speech Characteristics

  • continuous breathiness
  • diplophonia (two conncurent pitches)
  • audible inspiration or stridor
  • nasal emission
  • short phrases
  • hypernasality
  • rapid deterioration and recovery with rest
  • imprecise alternating motion rates (AMRs)

Related Physical Signs

  • weakness
  • flaccidity
  • fasciculations
  • hypoactive gag reflex
  • facial myokymia
  • synkesis
  • nasal backflow while swallowing

Ataxic Dysarthria

Ataxic dysarthria is a sensorimotor speech disorder occurring when the areas of the cerebellum which control movement and receive sensory input become damaged. The role of the cerebellum in feed-forward processing has been linked to speech motor control.1 Neuroimaging studies led by researchers Kristie Spencer and Dana Slocomb, Department of Speech and Hearing Sciences, University of Washington, Seattle, to establish two cerebellar cortical regions are responsible for the feedforward motor commands for speech: the anterior paravermal and superior lateral areas. Previously ataxic dysarthria had been classified as a disorder of motor execution, focusing on uncoordinated and hypotonic muscles.²

Speech Characteristics

  • irregular articulatory breakdowns
  • excess and equal stress
  • distorted vowels
  • excessive loudness variation
  • irregular AMRs

Related Physical Signs

  • dysmetric jaw, face, and tongue AMRs
  • head tremor

Motor nerve difficulties clearly contribute to ataxic dysarthria but this doesn’t address the processing abnormalities controlled by the cerebellum that take place during the planning phase of speech.

Treatment and Magement


The management focus of a speech-language specialist will be to help a person adapt and compensate for speech difficulties by improving comprehensibility and by teaching the use of augmented and alternative communication (AAC) skills and devices.

The two forms of AAC are

  • unaided-manual signs, gestures, body posture, and finger spelling (sign language)
  • aided-line drawings, pictures, communication boards, tablets, speech-generating devices

Training Respiration

  • Make postural changes while sitting upright to improve breath support for speech
  • Inhale deeply before speaking (known as preparatory inhalation)
  • Optimize breath groups by speaking only the number of syllables that can be comfortably projected during the breath
  • Blow into a pressure threshold device with enough effort to strengthen weakened expiratory (exhaling) muscles
  • Improve strength of the inspiratory (inhaling) muscles to allow sustained or repeated inspirations
  • Learn to use maximum vowel prolongation tasks to improve duration and loudness of speech
  • Practice controlledexhaling to improve control of speech
  • Blow into a water glass manometer to improve subglottal air pressure and respiratory support

Speech and Lauguage Therapy

Your SLP specialist will determine the best therapy plan based on your degree of speech difficulties. In neurodegenerative conditions like superficial siderosis, therapy is often appropriate. The goal of treatment is to maximize communication at each stage of progression but will not reverse the decline.

Sources: Superficial siderosis is a rare neurologic disease characterized by progressive sensorineural hearing loss, cerebellar ataxia, pyramidal signs, and neuroimaging findings revealing hemosiderin deposits in the spinal and cranial leptomeninges and subpial layer. The disease progresses slowly, and patients may present with mild cognitive impairment, nystagmus, dysmetria, spasticity, dysdiadochokinesia, dysarthria, hyperreflexia, and Babinski signs. Additional features reported include dementia, urinary incontinence, anosmia, ageusia, and anisocoria. Superficial siderosis MedGen UID: 831707 •Concept ID: CN226971 •Finding Orphanet: ORPHA247245
¹Spencer, K.A. & Slocomb, D.L. Cerebellum (2007) 6: 58. https://doi.org/10.1080/14734220601145459
²Yorkston KM, Beukelman DR, Strand EA, Bell KA. Management of motor speech disorders in children and adults. 2nd ed. Austin: PRO-ED, Inc.; 1999.
Living With SuperficialSiderosis Website PubMed Reference Library 
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