From the Guidelines
Dysarthria types can be differentiated by their distinct speech characteristics and underlying neurological causes, with the most recent evidence suggesting that accurate diagnosis and treatment require a comprehensive understanding of the underlying pathophysiology affecting speech motor control systems 1. The main types of dysarthria include:
- Flaccid dysarthria, resulting from lower motor neuron damage, causing muscle weakness and hypotonia, leading to breathy voice, nasal speech, and imprecise consonants.
- Spastic dysarthria, stemming from bilateral upper motor neuron damage, producing strained, harsh voice quality with slow, labored speech due to muscle hypertonia.
- Ataxic dysarthria, occurring with cerebellar damage, causing irregular articulatory breakdowns, abnormal prosody, and scanning speech as patients struggle with movement coordination.
- Hyperkinetic dysarthria, involving excessive, involuntary movements from basal ganglia disorders like Huntington's disease, resulting in unpredictable disruptions, vocal arrests, and variable rate.
- Hypokinetic dysarthria, typically seen in Parkinson's disease, presenting with reduced movement amplitude, monotone speech, rushed articulation, and decreased loudness.
- Mixed dysarthria, combining features of multiple types, occurring when neurological damage affects several motor systems simultaneously, as seen in conditions like ALS or multiple sclerosis.
According to the most recent guidelines, the management of functional communication, swallowing, cough, and related disorders requires a multidisciplinary approach, including education, symptomatic treatment, psychological support, and medical management 1. The treatment of dysarthria should focus on improving speech characteristics, reducing symptoms, and enhancing the patient's quality of life. The use of strategies such as reduction of excessive musculoskeletal tension, elimination of secondary or accessory movements, and focusing on normal movements and sounds can be effective in improving speech production 1. Additionally, cognitive behavioral therapy and psychological support can help address psychosocial issues and improve overall communication skills 1.
In terms of specific treatment approaches, the guidelines suggest that traditional treatment approaches used for developmental and neurological articulatory disorders may be effective, and that some patients may benefit from being taught simple compensatory strategies for word retrieval deficits and similar difficulties 1. The use of selective serotonin reuptake inhibitor (SSRI) antidepressants or low-dose amitriptyline may be helpful for globus, and providing information and advice to reduce acid reflux can also be beneficial 1.
Overall, the accurate diagnosis and treatment of dysarthria require a comprehensive understanding of the underlying pathophysiology affecting speech motor control systems, as well as a multidisciplinary approach to management, including education, symptomatic treatment, psychological support, and medical management 1.
From the Research
Types of Dysarthria
The six major types of dysarthria are:
- Flaccid dysarthria: associated with lower motor neuron impairment 2
- Spastic dysarthria: associated with damaged upper motor neurons linked to the motor areas of the cerebral cortex 2
- Ataxic dysarthria: primarily caused by cerebellar dysfunction 2
- Hyperkinetic dysarthria: related to a disorder of the extrapyramidal system 2
- Hypokinetic dysarthria: related to a disorder of the extrapyramidal system 2
- Mixed dysarthria: associated with damage in more than one area, resulting in speech characteristics of at least two groups 2, 3
Characteristics of Dysarthria
The features of the speech disturbance of these six major types of dysarthria are distinctive and can assist with diagnosis 2.
- Hypokinetic dysarthria is characterized by a reduction in movement and is often seen in patients with Parkinson's disease 4
- Ataxic dysarthria is characterized by a lack of coordination and is often seen in patients with cerebellar ataxia 4
- Mixed dysarthria can have a combination of hypokinetic, ataxic, and spastic components, and is often seen in patients with multiple system atrophy 3
Diagnosis and Classification
The classification of dysarthria can be challenging, and the accuracy of perceptual analysis alone is low 5.
- The inter-observer agreement between paired groups is also low, with a kappa value ranging from 0.16 to 0.32 5
- The level of experience in neurology does not have a significant influence on the accuracy of classification 5
- Longitudinal measures of segmental durations can provide valuable information on the progression of dysarthria in patients with motor neuron disease 6