CODI 555 Motor Speech Disorders
Lecture 4: Basal Ganglia Disorders:  Hypokinetic/Hyperkinetic Dysarthria

---

 Basal Ganglia Control Circuits

•  Consist of several intertwining loops among the basal ganglia nuclei & thalamic nuclei
•  Striatum (caudate & putamen) is receiver of input to basal ganglia
•  Frontal cortex especially premotor area
•  Thalamic nuclei
•  Substantia nigra
•  Striatum sends output to substantial nigra & globus pallidus
•  Globus pallidus is site or origin for major efferent (output) from basal ganglia

 Basal Ganglia Pathways

•  Loops
•  Striatum to globus pallidus to thalamus to cortex to striatum
•  Striatum to substantia nigra to striatum
•  Globus pallidus to subthalamus to globus pallidus
•  Efferent pathways - major pathway is from globus pallidus to ventrolateral nucleus of the thalamus and then back to cortex

 Functions of the Basal Ganglia Control Circuits

•  Site for 2 influential neurotransmitters - dopamine and acetylcholine
•  Balance between these two NT within the striatum is important for motor control
•  Regulation of amplitude, velocity and initiation of movement
•  Probably aid in generating components of motor speech programs
•  Modulate cortical discharges/ suppression of unwanted movements

 Effects of Lesions within Basal Ganglia Circuits

•  Hypokinesia - reduced mobility
•  Increase in muscle tone
•  Resistence to movement
•  Movements are slow, stiff and difficult to initiate or stop
•  Results from lack of dopamine in basal ganglia circuits
•  Hyperkinesia - involuntary movements
•  Excessive, unpredictable increases in muscle tone and movement
•  Result of excessive activity in dopaminergic nerve fibers

 Hypokinetic Dysarthria: Common Etiologies

•  Degenerative diseases - Parkinson’s disease, nigrostriatal degeneration, dementing diseases such as Alzheimer’s and Pick’s
•  Multiple or bilateral strokes affecting basal ganglia
•  Toxic-metabolic - antipsychotic medications, MPTP, chronic heavy metal exposure, Wilson’s Diseas
• TBI - repeated head trauma as in boxers
• Infectious - viral encephalitis

 Hypokinetic Dysarthria:  Speech Musculature Deficits

•  Resting tremor in jaw, lip, tongue
•  Rigidity - cogwheel rigidity
•  Bradykinesia - freezing
•  Hypokinesia/akinesia - reduced frequency of swallow

 Hypokinetic Dysarthria: Other Neuromuscular Deficits

•  Resting tremors of head, limbs, pill-rolling
•  Festinating gait
•  Decrease in spontaneous movements such as arm swing, limb gestures during speech, eye-blinking, head movements to accompany eye movement
•  Micrographia
•  Masked facies
•  Loss of postural reflexes

 Hypokinetic Dysarthria: Nonspeech Oral Mechanism Deficits

•  Face masked or expressionless at rest
•  Infrequent swallows resulting in drooling
•  Tremor of jaw, lips, tongue at rest and in sustained postures
•  Direction and rhythm of movements normal
•  Rate of individual movements may be slow, repetitive movements may be fast
•  Range and force are reduced; tone is excessive

 Hypokinetic Dysarthria: Patient Perceptions & Complaints

•  Weak or quiet voice
•  Can’t be heard in noise
•  Rate is too fast- speech indistinct
•  Trouble starting speech or “stutter”
•  Voice lacks emotional tone
•  Problems with drooling or swallowing

  Hypokinetic Dysarthria: Distinguishing clusters

•  Prosodic insufficiency (monopitch, monoloudness, reduced stress, short phrases, variable rate, short rushes of speech and imprecise consonants)

 Hypokinetic Dysarthria: Most Distinctive Speech Deviations

•  Monopitch
•  Monoloudness
•  Reduced overall loudness
•  Variable rate
•  Short rushes of speech
•  Some inappropriate silences

 Hyperkinetic Dysarthria: Common Etiologies

•  Damage to basal ganglia control circuits, portions of cerebellar control circuits or indirect activation pathways
•  Often result of neurochemical abnormalities rather than structural lesions
•  Degenerative diseases - Huntington’s
•  Toxic-metabolic - neuroleptic or antipsychotic drugs, tardive dyskinesia
•  Unknown etiologies - Tourette’s, Meige’s syndrome

 Hyperkinetic Dysarthria: Neuromotor Deficits

•  Abnormal involuntary movements occur at rest, during sustained postures or during voluntary movement
•  “hyper” refers to excessive or extra movements and does not imply that the speed of the involuntary movements is fast
•  Rate of movements can range from very fast to slow
•   Pattern of Movements can be rhythmic or irregular
•  Generally, voluntary movements of affected body parts is slow

 Hyperkinetic Dysarthria: Types of Movement Disorders

•  Dyskinesia
•  Myoclonus
•  Tics
•  Chorea
•  Ballism
• Athetosis
• Dystonia
• Spasm
• Tremor

 Hyperkinetic Dysarthria:  Patient Perceptions & Complaints

•  Nonrhythmic hyperkinesias - slurred, slow or halting speech -“hard to get out”
•  Feelings of tightness, inability to move affected structure
•  Laryngeal hyperkinesias - shaky voice, voice is tight or closes off, “voice doesn’t want to come out”
•  Shortness of breath/fatigue during speech but not in nonspeech activities
•  Development of “sensory tricks”

 Hyperkinetic Dysarthria: Chorea

•  Possible drooling, chewing and swallowing problems
•  Transient and unpredictable symptoms including hypernasality, strained-harshness, breathiness, articulatory distortions, loudness variations and sudden forced inspiration and expiration
•  Above combined with attempts to avoid/compensate often result in prolonged intervals and phonemes, variable rate, inappropriate silences, voice arrest and disturbed stress

 Hyperkinetic Dysarthria:  Dystonia

•  Complain of food getting stuck in throat; chewing difficulty
•  Movements most evident at rest or during sustained postures
•  Nearly all aspects of movement disturbed
•  Imprecision and irregular articulatory breakdowns
•  Inappropriate variations of loudness and rate
•  Strained harshness, transient breathiness, audible inspiration

 Hyperkinetic Dysarthria:  Spasmodic torticollis

•  Affects cervical neck muscles
•  Effects on speech thought to be secondary to abnormal neck positions
•  Usually articulatory and laryngeal in nature
•  Slow initiation of speech, reduced maximum duration, reduced pitch and pitch variability, dysphonia and reduced rate

 Hyperkinetic Dysarthria: Palatopharyngolarygneal myoclonus

•  Pt.  May complain of earclicks but usually unaware of speech symptoms
•  Brief voice arrests or myoclonic beats
•  Brief silent intervals
•  Occasional, intermittent hypernasality

 Hyperkinetic Dysarthria:  Action Myoclonus

•  Occasional voice arrests
•  Slow rate, imprecision, marked irregularity of AMR’s with increased rate
•  Awareness of imprecise speech and reluctance to speak at normal or rapid rates