Hypokinetic Dysarthria Flashcards
(38 cards)
Definitions of Hypokinetic Dysarthria
Caused by any process that damages basal ganglia (extrapyramidal system)
Speech characteristics: harsh vocal quality, reduced stress, monoloudness, imprecise consonants
May manifest in any or all levels of speech
Most evident in voice, articulation, and prosody
Reflects effects of rigidity, reduced force and range of movement, and slow but sometimes fast repetitive movements
Neurologic Basis of Hypokinetic Dysarthria
Unique, as only dysarthria with:
-Increased rate as symptom
-Mainly one causative factor (parkinsonism)
Symptoms affect muscles of speech
Symptoms caused by dysfunction to basal ganglia or to basal ganglia’s neural connections to other parts of CNS
Hypokinetic
less motion
Characteristics of Parkinsonism
Distinctive collection of symptoms
-Resting tremor
-Bradykinesia: slow, reduced range of movement
-Rigidity
-Akinesia: delay in initiation of movements
Postural reflexes
Causes of Parkinsonism
Caused by dysfunction in basal ganglia
Depends on balanced interaction of several neurotransmitters, including dopamine (inhibitory) and acetylcholine (excitatory)
Reduction of dopamine in striatum
Causes too much acetylcholine
-Thought to be primary cause of rigidity, bradykinesia, and other symptoms of parkinsonism
Varied causes of reduced dopamine
Causes of Hypokinetic Dysarthria
Parkinsonism: collective term for different disorders sharing many similar symptoms
Major causes of hypokinetic dysarthria
- Idiopathic Parkinson’s disease
- Neuroleptic-induced parkinsonism
- Postencephalitic parkinsonism
- Traumatic head injury
- Toxic metal poisoning
- Stroke
Speech Characteristics of Hypokinetic Dysarthria
Quite distinctive
Most noticeable errors: prosody and articulation
Most errors result of bradykinesia, akinesia, and muscle rigidity
In severe cases tremors cause tremulous phonations
There are significant individual differences
Prosody
Monopitch, reduced stress, and monoloudness most common
Articulation
Imprecise consonants, repeated phonemes, palilalia
Phonation
Harsh/breathy quality, aphonia, low pitch
Respiration
Sometimes noted
Resonance
If present, mild hypernasality
Key Evaluation Tasks for Hypokinetic Dysarthria
Conversational speech and reading
- Evoke many errors of prosody
- Detect short rushes
Speech alternate motion rates (AMRs)
-Highlight articulation errors
Vowel prolongations
-Assess vocal quality
Treatment of Hypokinetic Dysarthria
Divided into three categories
Pharmacologic
-Most widely used
-L-Dopa
Surgical
- Ablation procedures (making lesion in basal ganglia)
- Deep brain stimulation
Behavioral: speech-language therapy
Pharmacologic Treatments for Parkinsonism
Replacing dopamine in striatum
- Problem: direct dosages of dopamine unable to reach striatum
- Precursor of dopamine, L-dopa used to reach striatum and then converted to dopamine
Correct neurotransmitter imbalance by decreasing acetylcholine activity in striatum
- Anticholinergic drugs
- Sometimes combined with L-dopa treatment
Surgical Treatments for Parkinsonism
Complicated and invasive
Used when patient incapacitated and medications ineffective
Two general types
- Ablative surgery (thalamotomy and pallidotomy)
- Deep brain stimulation
Ablative procedures
Lesions are purposefully produced in small amounts of brain tissue in order to reduce neuron activity in a specific area of the brain.
Pallidotomy
A hole is drilled into the skull, and a small electrical probe is inserted into the globus pallidus of the basal ganglia. The tip of the probe is then heated for a short time to destroy nearby neurons.
The loss of these neurons reduces brain activity in that part of the basal ganglia, and consequently, a patient’s muscle rigidity, tremor, and bradykinesia may be reduced to some degree.
Deep brain stimulation
More effective. It does not result in permanent lesions, and can be reversed.
In this treatment, a small electrode is inserted into either the globus pallidus or subthalamic nucleus. When turned on, the electrode sends a low-level electrical current to the surrounding neurons, which interrupts neural activity in that part of the brain. The electrode is controlled and powered by a small pulse generator near the collar bone (under the skin).
Stem-Cell Implantation
Stem cells unique as can transform themselves into different types of cells
Found naturally in embryos, in adult tissues, and can be grown in labs
Significant amount of research concentrated on using stem cells to treat parkinsonism
Results preliminary but encouraging
Few human trials conducted
Behavioral Treatments for Parkinsonism
Behavior- and instrumentation-based tasks important part of clinical treatment plan
Articulation
- Most common deficit: imprecise consonants due to reduced range of motion in articulators
- Compounded by increased rate
Treatment types
Rate reduction, stretching, traditional articulation tasks
Rate reduction
slowing the rate of speech can improve articulation because it allows the articulators more time to reach the target positions and also gives listener more time to process what is being spoken. There are a different rate control procedures, and are as follows:
There are a different rate control procedures, and are as follows:
Pacing Boards
Hand or finger tapping
Alphabet boards
Delayed Auditory Feedback
Reciting syllables to a metronome
Pacing Boards
Devices with finger-width slots. Patient is instructed to place a finger in the first slot and begin reading or repeating a short sentence; each time a word is spoken the patient moves the finger to the next slot.
Drawback: reluctance to use in public
