Motor Speech Disorders
Disorders of speech resulting from neurologic impairment affecting the planning, programming, control or execution of speech.
They encompass apraxia of speech and the dysarthrias.
They are NOT language, cognitive‐communication, or swallowing problems.
The Dysarthrias
A group of motor speech disorders resulting from
disturbances in muscular control or execution over the
speech mechanism
Due to damage of the central or peripheral nervous
system◦Result from paralysis, paresis, incoordination, involuntary
movements, or excessive or variable tone of the speech musculature
respiratory =
inadequate loudness
phonation =
Hoarseness, harshness, breathiness, diplophonia, strained-strangled quality
resonance =
hypernasality
articulation =
Distortion (or substitution or omission)
prosody =
Monopitch, monoloudness, excess & equal stress, rate too fast/too slow
Etiology of Dysarthria
StrokeTraumaInfectious processesTumorsProgressive neural diseasesDemyelinating diseases (e.g., Guillain‐Barré - an acute form of polyneuritis, often preceded by a respiratory infection, causing weakness and often paralysis of the limbs) Muscle diseases (e.g., muscular dystrophy - a hereditary condition marked by progressive weakening and wasting of the muscles.)
Toxic agents
Apraxia of Speech (AOS)
A neurogenic speech disorder
results from impairment of the capacity to program sensorimotor
commands to position and move muscles for the volitional
production of speech
in the absence of paralysis, paresis, incoordination, involuntary
movements, or excessive or variable tone of the speech musculature
Frequently co‐occurs with aphasia
May co‐occur with dysarthria
Etiology: most often stroke◦ Except for the progressive form: primary progressive
apraxia of speech (PPAOS) for which we don’t know the etiology
Beginning differential diagnosis
DYSARTHRIA
Problem with muscular control or execution
Paralysis, paresis, incoordination, involuntary movements, excessive or variable tone
AOS
Problem with motor planning
NO paralysis, paresis, incoordination, involuntary movements, excessive or variable tone
Methods for studying motor speech disorders - perceptual
◦ Still considered “gold standard”◦ Relies on clinician’s ability to analyze speech by listening to it
◦ Information from the medical history and from careful visual and tactile observation provides confirmatory evidence
◦ Most widely used method clinically◦ Can be unreliable if used by someone not trained and practiced in listening
critically to disordered speech
◦ Ultimate outcome of treatment is how well the speaker is able to be understood by a listener (if speaking is a realistic goal)
Methods for studying motor speech disorders - instrumental
Acoustic
Uses instrumentation to analyze speech waveform
Studies have shown that a fixed set of acoustic measurements
does not necessarily correlate highly with perceived severity of
dysarthria
Little consensus about selection of measures that correlate with
perceptual ratings of quality
Generally used to explore speech impairment in greater detail, with quantifiable, reliable measurements
Used to confirm perceptual judgments◦ Useful for providing feedback in some forms of treatment, in
objectifying progress, although changes in the acoustic signal don’t always yield big payoffs in improved intelligibility
Methods for studying motor speech disorders - instrumental - physiologic
Uses instrumentation to study movements of speech structures and
the airstream, muscle contractions, biomechanical activity, &
relationships between neural activity and movement
Includes EMG, EGG, spirometry, nasal accelerometry
Physiologic activity can be imaged with fMRI, PET, SPECT, TMS, MEG
Generally used to try to correlate perceptual judgments with what’s happening physically in order to refine our understanding of the relationships
May serve as feedback during some forms of treatment, or to objectify progress, although changes in physiologic measurements don’t always yield big payoffs in improved intelligibilit
Methods for studying motor speech disorders - instrumental - visual imaging methods
◦ Instrumental visual image is interpreted perceptually, so
really combines instrumental & perceptual methods ◦ Include
◦ Videofluoroscopy
◦ Nasendoscopy◦ Laryngoscopy◦ Videostroboscopy
Duffy uses ........... which is the most widely used in the U.S.
Darley, Aronson, & Brown (DAB; also called the Mayo Classification System)
Other methods of classifying dysarthria: lesion site
- lesion site
◦ Peripheral Dysarthrias
◦ Myopathic (muscle weakness) ◦ Myoneural (connecting muscles & nerves) ◦ Lower motor neuron
◦ Central Dysarthria
◦ Spastic ◦ Dyskinetic ◦ Ataxic
◦ Mixed Dysarthria
Other methods of classifying dysarthria: age of onset
◦ Congenital/developmental
◦ Acquired
Other methods of classifying dysarthria: course
◦ Chronic/static◦ Improving◦ Progressive/degenerative
◦ Exacerbating‐remitting
purposes of motor speech examination
Description of speech features
establishing diagnostic possibilites
Establishing a diagnosisEstablishing possibilities for localization and disease diagnosis
Specify severity
purposes of motor speech examination - Description of speech features
Normal or abnormal?
purposes of motor speech examination - Establishing diagnostic possibilities
◦ Neurologic?◦ If not, organic or psychogenic?◦ Recent onset or longstanding?
◦Is it a MSD?◦ If so, dysarthria or apraxia of speech? ◦ If dysarthria, what kind of dysarthria?
purposes of motor speech examination - Establishing a diagnosis
◦ Process of elimination◦ List all possibilities that it could be and look for evidence to rule in or rule
out◦ Sometimes it’s as valuable to rule things out as to get a definitive diagnosis
R/O dysarthriaR/O apraxia vs dysarthria R/O malingering Evaluate and treat speech
purposes of motor speech examination - Establishing possibilities for localization and disease diagnosis
◦ State implications of diagnosis
◦ What does it imply for localization?
◦ If a neurologic dx has been made, is the speech dx compatible with it? ◦ REMEMBER:
We diagnose the speech problem, not the medical) condition that causes the speech problem
However, sometimes it may be appropriate to state what medical condition the MSD is usually associated with, especially if the medical dx is uncertain or is for a condition that is not usually associated with what you’ve observed◦ e.g., “The patient demonstrates a mixed flaccid‐spastic dysarthria which is most often
associated with amyotrophic lateral sclerosis and a slow, insidious onset, not with the sudden onset typical of stroke.”
purposes of motor speech examination - Specify severity
Match to patient’s complaints; gross mismatches may suggest psychogenic
etiology
Influences prognosis & management decisions
Initial estimates serve as baselines against which improvement or deterioration
are measured
Motor Speech Examination - History (don’t forget to watch and listen)
◦Introduction, discuss patient’s purpose
◦Basic data (review for accuracy)
◦ Address & phone
◦ Age◦ Education◦ Occupation
◦ Marital/family status (hearing loss of spouse)◦ History of childhood speech & language problems
Motor Speech Examination - Onset and course
◦ When did it start?◦ Sudden or gradual?◦ Better, worse, or same now?◦ Any other problems start at the same time? Before? After
Motor Speech Examination - Associated deficits?
◦ Eating/swallowing◦ Change in emotional expression? Laugh or cry more easily?◦ Any medications?◦ Dental status◦ Hearing status◦ Visual acuity (If glasses are prescribed, pt. should wear them) ◦ Other medical problems?
Motor Speech Examination - Patient’s perception of deficit
◦ Describe in own words◦ Noticed any changes?
Motor Speech Examination - Consequences of problem
◦ Useful for determining extent of disability and barriers to participation
◦ Do people have trouble understanding you? When? What do you do?
◦ Do you ever have to write to make yourself understood? Has your problem affected your work? Does it prevent you from doing anything?
Motor Speech Examination - Management
◦ What have you done to compensate? How has it worked?◦ Have you had any help? When/how long? What was done? Did it
work?◦ Do you think you need help with your speech now?
Motor Speech Examination - Awareness of diagnosis and prognosis
◦ Find out how much they understand so you know how to share info ◦ What have you been told about the cause of the problem?◦ In view of the diagnosis, what’s going to happen?
Examination of speech mechanism - salient features
Salient features: features that contribute most directly to diagnosis
◦Strength: reduced, usually consistently but sometimes progressively
◦ Speed: reduced or variable (except in hypokinetic dysarthria, when it is increased but accompanied by reduced ROM)
Examination of speech mechanism
◦ Range of motion (ROM): reduced or variable
◦Steadiness: unsteady, either rhythmic or arrhythmic
◦ Tremor, hyperkinesias◦ Tone: a normal property of muscle that establishes its
appearance as neither too taut nor too flabby; a constant state of readiness◦ May be increased, decreased, or variable
◦Accuracy: inaccurate, either consistently or inconsistently
Examination of speech mechanism - Confirmatory signs
◦Not always present◦ Not diagnostic of MSDs, but are clues that help confirm or
refute a diagnosis
◦ Include:
◦ Atrophy◦ Fasciculations◦ Uninhibited laughing/crying ◦ Pathologic reflexes◦ Etc.
Examination of speech mechanism during nonspeech activities - face at rest
◦ relax, look forward (or close eyes), let
lips part to breathe quietly through
mouth.
◦Look for:
◦ Asymmetry◦ Expressionless, masklike, and unblinking◦ Abnormal, spontaneous, involuntary movements ◦ Tremors of lips, around mouth or chin
Examination of speech mechanism during nonspeech activities - Face during sustained postures:
◦Lip retraction◦Lip rounding or pursing
◦Sustained mouth opening
◦Cheek puffing
Examination of speech mechanism during nonspeech activities - Face during movement (emotional responses and volitional nonspeech tasks)
Expressiveness: observe emotions, try to elicit spontaneous smile and compare with voluntary lip retraction; look for difficulty inhibiting laughter or crying
AMRs*: as rapidly and steadily as possible; observe rate, range, regularity of movement, involuntary movements◦ Lip pursing◦ Lip retraction
◦ Cheek puffing*AMR = alternating motion rate
Examination of speech mechanism during nonspeech activities - jaw at rest
◦ Hang lower than normal?
◦ Involuntary movements?
Examination of speech mechanism during nonspeech activities - Jaw during sustained posture
◦ Mouth opening as wide as possible
◦ Deviation?◦ Resistance to opening? To closing?◦ Normal bulk of masseter and temporalis when biting down?
Examination of speech mechanism during nonspeech activities - Jaw during movement
◦ AMRs: open and close rapidly
Examination of speech mechanism during nonspeech activities - Tongue at rest
◦ Some spontaneous movement is common◦ Look for atrophy, fasciculations, or large‐scale involuntary
movements
Examination of speech mechanism during nonspeech activities - Tongue during sustained postures
◦ Protrusion
◦ If deviates, repeat and note if consistent to one side, since mild deviation is natural but inconsistent re: side
◦ Lateralization
◦ Inside mouth◦ Outside mouth
Examination of speech mechanism during nonspeech activities - Tongue during sustained postures
◦ Protrusion
◦ If deviates, repeat and note if consistent to one side, since mild deviation is natural but inconsistent re: side
◦ Lateralization
◦ Inside mouth◦ Outside mouth
Examination of speech mechanism during nonspeech activities - Tongue during movement
◦ Side‐to‐side
◦ Slow, one side at a time
◦ AMR
Examination of speech mechanism during nonspeech activities - Tongue strength
◦ Frontal◦Lateral inside & outside mouth
Examination of speech mechanism during nonspeech activities - Velopharynx at rest
◦ SP hang low?◦ Symmetric faucial arches?
◦ Involuntary movements?
Examination of speech mechanism during nonspeech activities - Velopharynx during movement
◦ Prolong /ɑ/
◦ Elevation? Symmetric?
◦ Evidence of nasal airflow on mirror?
Staccato / ɑ /
Evidence of nasal airflow on mirror during /s:/ or rep. of /pΛ/
If real question, use videofluoroscopy
Examination of speech mechanism during nonspeech activities - Larynx
◦ Cough
◦ Sharpness◦Coup de glotte (glottal coup): sharp glottal stop or grunting
sound
◦ Sharpness◦Inhalatory stridor?◦Consider requesting laryngeal exam, pursuing EGG or
acoustic analysis
Examination of speech mechanism during nonspeech activities - Respiration
◦ Quiet breathing
◦ Posture? ◦ SOB? Rapid, shallow, labored? ◦ Abdominal/thoracic movements limited in ROM? ◦ Shoulder movements? ◦ Neck extension/retraction? ◦ Regular rate?
◦ Sharpness of cough or glottal coup ◦ Weak cough with reduced ROM of abdominal thoracic excursion: respiratory weakness
◦ Manometer ◦ Maintain a stream of bubbles at depth of 5 cm for 5 sec
Examination of speech mechanism during nonspeech activities - Reflexes
Not involved in speech production, but can be confirmatory evidence about
localization
Normal reflexes: presence is reflection of normal NS function; absence reflects
PNS pathology◦ Gag/pharyngeal reflex: back of tongue, PPW, faucial pillars
Afferent path CN IX (glossopharyngeal)
Motor path CN IX & X (vagus)
Characterized by palatal elevation, tongue retraction, sphincteric contraction of
pharyngeal walls
In general, significant only if absent or asymmetric (hypoactive on less responsive side)
Examination of speech mechanism during nonspeech activities - Primitive reflexes:
present during infancy but tend to
disappear during NS maturation
Presence beyond infancy associated with CNS pathology, especially in frontal lobe cortical and subcortical regions◦ Be cautious if presence is weak or equivocal – a small percentage of
“normal” adults exhibit primitive reflexes
“release phenomenon” – reduction of cortical inhibitory influence on lower brain centers
Examination of speech mechanism during nonspeech activities - sucking reflex
stroke upper lip with tongue blade, beginning at lateral aspect and moving medially; do on both sides
No response in normal adults
Pursing lips: positive or pathologic result; can be confirmatory of UMN
disease, esp. diffuse damage to premotor cortex; frequently seen in dementia
When very strong, may purse lips as object approaches mouth, or turn mouth toward tactile stimulation at corner of mouth or cheek: called rooting reflex
Examination of speech mechanism during nonspeech activities - Snout reflex
light tap of finger on philtrum or tip of nose; or pressure of index finger on midline of upper lip and philtrum
◦ No response in normal adults
◦ Positive or pathologic response: protrusion and elevation of lower lip and depression of lateral angle of mouth
Examination of speech mechanism during nonspeech activities - Voluntary vs. automatic nonspeech movements of speech muscles
◦ Goal – test for nonverbal oral apraxia ◦ Focus on ability to perform without off-target approximations, frank errors, or frustrating
awareness that performance is incorrect with accompanying attempts at self-corrections
◦ Elicit with spoken command first, give model if necessary
◦ Often improve on imitation ◦ Able to perform reflexively or unconsciously, so be on the lookout so you can compare performance
Tasks for speech assessment - Vowel prolongation
◦ Pitch◦ Loudness◦ Quality◦ Duration◦ Steadiness◦ Observe face for movements
Tasks for speech assessment - Alternating Motion Rates (AMRs)
AKA diadochokinetic rates
Determine:
speed and regularity of reciprocal movements of jaw, lips, anterior and posterior tongue
Precision of artic movements
Adequacy of VP closure
Respiratory and phonatory support for sustained speech tasks
/pΛ/, /tΛ/, /kΛ/
Tasks for speech assessment - SMR: sequential motion rates
◦ Ability to move quickly from 1 artic position to another
◦ Useful when AOS is suspected◦ /pΛtΛkΛ/, buttercup, coffeepot, etc.
Tasks for speech assessment - Contextual speech
◦ Conversational and narrative speech
◦ Oral reading of standard passage
Tasks for speech assessment - Stress testing
◦ Use if
◦ LMN weakness of unknown cause is present◦ Pt. complains of changes in speech as day progresses or with physical
effort◦ Count as precisely as possible; continue without rest for 2-4 minutes ◦ Repeated readings of Grandfather Passage (or other passage)
Tasks for speech assessment - Assessing speech programming capacity
◦ If AOS is suspected
◦ If mute or barely able to speak, ask to sing familiar tunes or use automatic speech tasks
Tasks for speech assessment - published tests
◦ Frenchay Dysarthria Assessment - 2
◦ Apraxia Battery for Adults - 2◦ Apraxia of Speech Rating Scale
Tasks for speech assessment - Intelligibility
Degree to which a listener understands the auditory signal produced by the
speaker
Tasks for speech assessment - Comprehensibility
Degree to which a listener understands the auditory signal PLUS all info associated with it (e.g., gestures, facial expressions, prosody, familiarity with context, etc.)
Tasks for speech assessment - Efficiency
Rate at which intelligible or comprehensible information can be conveyed
Tasks for speech assessment - ALWAYS give estimate of
intelligibility or comprehensibility
◦be specific about the level of speech and context
Psychosocial Effects of Motor Speech Disorders - Patient Reported Outcome Measures (PROs)
◦Measures designed to elicit the patient’s perspective about the impact of the disorder and whether treatment is making a difference
◦Valuable for assessing the limitations to activity and participation
Psychosocial Effects of Motor Speech Disorders - Patient Reported Outcome Measures (PROs)
◦Dysarthria Impact Profile◦ Measures the psychosocial impact of acquired dysarthria from the speaker’s perspective in the areas of:◦ Self-perception◦ Self-concept
◦ Self-esteem
Psychosocial Effects of Motor Speech Disorders - Communicative Participation Item Bank
◦ Developed for use by community-dwelling adults with any communication disorder
Flaccid Dysarthria
Produced by LMN lesion (bulbar palsy) ◦ Nuclei of spinal or cranial nerves◦ Axons◦ Myoneural junction
LMN lesion: all movement is affected (reflexive, automatic, & voluntary)
Reduced muscle tone & ROM
Atrophy & fasciculations
◦ Fasciculations: visible, arrhythmic twitches or dimplings in resting m. 2° spontaneous motor unit discharges; results from n. degeneration or irritation
Weakness of muscle contraction
Flaccid Dysarthria - common etiologies - neuromuscular junction diseases - myasthenia gravis
◦Neuromuscular junction diseases
◦Myasthenia gravis (MG)
Autoimmune disease that destroys acetylcholine (ACh) receptors on
muscles, making them less responsive to the ACh that triggers
contraction
Abnormally rapid weakening of voluntary muscles with use,
improvement with rest (which replenishes ACh supply)
Tensilon injection improves performance immediately after stress testing
Flaccid Dysarthria - common etiologies - neuromuscular junction diseases - botulism
◦ Botulism ◦ Botulinum toxin blocks release of ACh at presynaptic membrane
◦ Paralyzes affected muscles
Flaccid Dysarthria - common etiologies - vascular disorders
◦ Brainstem stroke
Flaccid Dysarthria - common etiologies - infectious processes
◦ Polio (poliomyelitis) (myelitis: inflammation of spinal cord) ◦ Herpes zoster (shingles - an acute, painful inflammation of the nerve ganglia, with a skin eruption often forming a girdle around the middle of the body. It is caused by the same virus as chickenpox.) ◦ Opportunistic infections assoc with AIDS ◦ Encephalitis ◦ Meningitis
Flaccid Dysarthria - common etiologies - Demyelinating diseases
◦ Guillain-Barré: demyelinization of spinal & cranial nerves
Flaccid Dysarthria - common etiologies - tumors
particularly at the base of the skull
Flaccid Dysarthria - common etiologies - Muscular diseases
◦ Muscular dystrophy: degeneration of m fibers and proliferation of connective tissue
◦ Poliomyositis: disease of striated muscles associated with infections
- myositis: inflammation of muscles
Flaccid Dysarthria - common etiologies - Degenerative diseases
◦ Progressive bulbar palsy: LMN weakness of CN muscles; dysarthria &
dysphagia are predominant signs
Flaccid Dysarthria - common etiologies - others
◦Radiation therapy for carcinoma ◦Surgery/other trauma ◦Idiopathic mononeuropathies (neuropathy - dysfunction of peripheral nerves causing numbness & weakness)
◦ Bell’s palsy: CNVII
Flaccid Dysarthria - confirmatory signs - CN V (5)
◦ Trigeminal ◦ Maxillary branch – sensory info ◦ Mandibular branch – jaw movement
◦ Unilateral damage:◦ jaw deviates to weak side when opened ◦ No perceptible impact on speech
◦ Bilateral damage:◦ jaw hangs open◦ Profound effect on bilabials, labiodentals, lingualveolar, and lip and tongue
adjustment for many vowels and glides
Flaccid Dysarthria - confirmatory signs - ◦ CN VII (7)
◦ Facial◦ Perioral fasciculations
◦ Unilateral
◦ Effects more visible than audible ◦ Face sags on affected side, no wrinkles or NL fold ◦ Pocketing of food on affected side ◦ Reduced retraction & puffing, cheek flutter
◦ Bilateral ◦ Effects more audible than visible ◦ Face looks symmetric, but weakness is present ◦ Distortions of bilabials, labiodentals, and vowels that require lip rounding or spreading
Flaccid Dysarthria - confirmatory signs - CN X (10) w/ unilateral
◦ Vagus – important branches for speech:
◦ Pharyngeal branch◦ Superior laryngeal branch ◦ Recurrent laryngeal branch
◦ Unilateral
Soft palate lower on weak side at rest, pulls up toward strong side on phonation,
reduced gag on weak side
Superior laryngeal n.: vf shorter
Recurrent laryngeal n.: vf fixed in paramedian position
Both sup. & rec. : paralyzed in abducted position
May hear hypernasality, stridor or breathiness
Flaccid Dysarthria - confirmatory signs - CN X (10) w/ bilateral
◦ SP low at rest, minimal or no movement on phonation, absent gag ◦ Superior laryngeal n.: bowed vfs◦ Recurrent laryngeal n.: both cords in paramedian position◦ Both superior & recurrent: both cords in abducted position◦ Hypernasality, nasal emission, breathiness, stridor
Flaccid Dysarthria - confirmatory signs - CN XI (11)
◦ (Spinal) accessory nerve◦ Unilateral: generally no effect on speech ◦ Bilateral
◦ May affect respiration, phonation, and resonance mildly, but can’t be separated from CNX effects
Flaccid Dysarthria - confirmatory signs - ◦CN XII (12)
◦ Hypoglossal
◦ Unilateral
◦ Tongue atrophy & fasciculations ◦ Deviation to weak side on protrusion ◦ Imprecise articulation
◦ Bilateral ◦ Tongue atrophy & fasciculations ◦ Minimal ROM ◦ Pocketing of food, difficulty handling saliva ◦ Imprecise articulation of all lingual sounds
Flaccid Dysarthria - Best distinguishing features for flaccid dys.:
◦ Hypernasality, nasal emission, continuous breathiness, stridor
◦May also hear:◦ Hoarseness, harshness, diplophonia, monopitch, monoloudness, short
phrases, imprecise articulation
◦ Everything we hear can be traced to weakness
Spastic Dysarthria
Bilateral UMN lesions; pseudobulbar palsy◦ Because most speech LMNs are bilaterally innervated
from UMNs, bilateral UMN lesions are generallyrequired to produce spastic dysarthria UMN ◦ Unilateral UMN lesions don’t generally have a major, long-term effect on speech, but we will discuss possible effects later
Spastic Dysarthria - etiology
◦ Vascular
Single brainstem stroke in vertebrobasilar artery distribution◦ R & L UMN pathways in close proximity
Bilateral cerebral hemisphere strokes◦ R & L UMN pathways not close in cerebral hemispheres ◦ Usually caused by 2 separate strokes◦ Lacunar infarcts
◦ Small deep infarcts in penetrating arteries
◦ Inflammatory disease
◦ Leukoencephalitis
Inflammation of white matter of brain or spinal cord
Causes necrosis of small blood vessels & surrounding
brain tissue
◦ Degenerative disease
◦ Primary lateral sclerosis
◦ Rare motor neuron disease ◦ Onset usually in 50s ◦ Dysarthria is often the first symptom
Spastic Dysarthria - Confirmatory signs:
◦ Hyperactive reflexes◦ Pathological reflexes◦ Chewing and swallowing problems ◦ Pseudobulbar affect◦ drooling
Spastic Dysarthria - Prominent speech characteristics
Strained-strangled voice quality, harshness, low pitch, reduced pitch variation,
reduced loudness variability
Hypernasality
Imprecise articulation
Slow rate, slow but regular AMRs
All can be traced to spasticity, slowness of movement, reduced ROM, & somewhat to weakness
Spastic Dysarthria - Best distinguishing speech features:
◦ Slow rate◦ Harsh, strained-strangled voice quality◦ Reduced variability of pitch and loudness ◦ Slow regular AMRs
palmomental reflex
The palmomental reflex or Marinesco-Radovici Sign or Kinn reflex or Marinesco Reflex is a primitive reflex consisting of a twitch of the chin muscle elicited by stroking a specific part of the palm.
jaw jerk reflex
The jaw jerk reflex or the masseter reflex is a stretch reflex used to test the status of a patient's trigeminal nerve and to help distinguish an upper cervical cord compression from lesions that are above the foramen magnum. caused by striking the chin when the mouth is open.
neuritis
a condition caused by inflammation of a nerve or nerves secondary to injury or infection of viral or bacterial etiology.
post-polio syndrome
Post-polio syndrome (PPS) is a condition that can affect polio survivors decades after they recover from their initial poliovirus infection. Unlike poliovirus, PPS is not contagious.
moyamoya disease
Moyamoya disease is a rare, progressive cerebrovascular disorder caused by blocked arteries at the base of the brain in an area called the basal ganglia.
- causes weakness and numbness
CADASIL
CADASIL (Cerebral Autosomal Dominant Arteriopathy with Sub-cortical Infarcts and Leukoencephalopathy) is an inherited form of cerebrovascular disease that occurs when the thickening of blood vessel walls blocks the flow of blood to the brain.