ataxic Flashcards
in ataxic dys it is a problem of?
coordination
Ataxic dysarthria is not caused by a lack of?
strength
ataxic dys is a ?
cerebellar control circuit dysfunction
what 2 subsystems are primarily affected in ataxic?
articulation and prosody
What is the function of the cerebellum?
imposes control on posture and movement initiated elsewhere
coordinates posture, locomotion and coordinated activities by adjusting activities of the indirect and direct motor systems and through them the activities of the lmn system
error control
What is the major function of the cerebellum?
error control
-makes sure u don’t overshoot target/undershoot monitors force etc..
Where does the cerebellum receive input from?
the motor cortex
where does the cerebellum provide output to
it receives info from the motor cortex and provides output to cortex through the thalamus and then to the peripheral system
what do lesions in the cerebellum cause?
hypotonia, and errors in force, speed, timing, range and direction of movements (coordination)
This reduced muscle tone and incoordination results in?
slow rate of spch and inaccuracy in speech production
what are the 3 lobes of the cerebellum?
anterior, posterior, flacculonodular
What does the anterior lobe consist of?
most of the vermis and the anterior aspect of the cerebellar hemispheres
what is the anterior lobe important for?
regulating posture, gait, and muscle tone of the trunk of the body
what lobe makes up the greater part of the cerebellum>
the posterior
T or F the posterior lobe is located btwn the anterior and flacculonodular lobe.
True
The posterior lobe is important for?
coordinating skilled, voluntary muscle activity and muscle tone
What are floccule?
small appendages in the posterior inferior region of he cerebellum
T or F the flocculonodular lobe includes the inferior part of the vermis and the attached flocculi
True
What is the vermis>
middle of the cerebellum
How many hemispheres does the cerebellum have?
2
Each side of the vermis is connected to the opposite thalamus and the opposite cerebral hemisphere. T or F
True
Does each cerebellar hemisphere control the ipsilateral or contralateral part of the body?
ipsilateral (right side of cerebellum controls the right side of body)
T or F the right side of the cerebellum controls the r side of the body but it controls the left cerebral hemisphere.
True
What are cells in the cortex of the cerebellum called?
purkinje cells
How many purkinje cells are in the cerebellum?
15 million
What do the purkinje cells make up?
the middle part of the cerebellar cortex
What do purkinje cells connect to?
they connect to other nuclei that is deep in the cerebellum (information is passed through these connections)
What is the dentate nucleus important for?
it is important in speech control as it aids in initiating movement and regulating posture
Tracts of nerve fibers that enter and leave the cerebellum pass through what 3 structures?
the inferior cerebellar peduncle
the middle cerebellar peduncle
superior cerebellar peduncle
The superior peduncle is a bridge btwn what two structures?
midbrain and cerebellum
the middle peduncle is a bridge btwn what two structures
pons and the cerebellum
the inferior peduncle is a bridge btwn what two structures
the medulla and cerebellum this is mainly an efferent pathway
T or F. Each cerebellar hemisphere connects to the rest of the nervous system through these three tracts of nerve fibers (superior, middle and inferior peduncles)
True
Not a lot is known about lesions in the cerebellum but lesions causing speech problems are usually bilateral or in the vermis or generalized
but it can be due to a more focal lesion as well
What can cause ataxic dys?
anything that damages the cerebellum including degenerative dz, inflammation, neoplastic problems, toxicity, metabolic, traumatic and vascular diseases
What are the 8 etiologies of ataxic dys?
degenerative dz inflammation neoplastic toxicity metabolic traumatic vascular dz
what are the two types of degenerative dz that can cause ataxic dys?
frederich’s ataxia
multiple sclerosis
what is frederich’s ataxia??
- symptoms show in childhood and progress over time
- hereditary
- due to an autosomal recessive pattern
- it ends in death after a course of about 20 yrs
- ataxic dys is common but not a first sign
what is multiple sclerosis?
- it can result in cerebellar lesions and ataxic dys
- but usually ms lesions aren’t just in the cerebellum
what are the three causes of vascular dz that can lead to a lesion in the cerebellum?
aneurysms
arteriovenous malformation (AVM’s)
cerebellar hemorrhages
what is arteriovenous malformation (AVM’s)
it is a tangle of blood vessels
What percent of metastatic brain tumors develop in the cerebellum?
25%
What is another name for punch drunk encephalopathy?
dementia pugilistica
what is punch drunk encephalopathy caused by?
TBI
boxers who have sustained hits to the head
it involves cerebellar dysfunction
what are some toxic-metabolic disorders that cause ataxic dys?
acute and chronic alcohol abuse
does acute alcohol abuse cause permanent ataxic dysarthria (normally)?
no it is normally temporary
T or F chronic alcoholism results in ataxic dys. sometimes but it may be more due to nutritional problems rather than the affect of alcohol.
True
Can severe malnutrition with vitamin deficiencies cause ataxic dysarthria?
yes
Can neurotoxic (harmful to nerve tissues) levels of certain drugs result in cerebellar symptoms?
Yes
lithium, Dilantin, valium
What are some other dz that may cause cerebellar damage?
hypothyroidism
normal pressure hydroencephalus (NPH)
what is hypothyroidism?
endocrine imbalance and when severe may lead to ataxic dys
- caused by not enough sevretion of thyroxin by the thyroid gland
- ataxic dys may be accompanied by hoarse, gravelly and excessively low pitched voice
What is normal pressure encephalopathy?
NPH: ventricles may be enlarged but CSF pressure is normal
what does the patient complain about?
slurred speech “sounds drunk”
limited alcohol intake results in quick deterioration of speech
stumble over words
bite their cheek when eating
cant coordinate breathing with speaking
swallowing complaints are less often than in flaccid or spastic
patnts report that slowing their speech improves intelligibility
T or F. ataxic dys may be valuable for neurologic localization.
True
What are the general clinical characteristics of ataxia?
problems standing and walking titubation abnormal eye movement hypotonia dysmetria dysdiadochokinesis ataxia: movements are halting inprecise, jerky, poorly coordinated lacking in speed and fluidity can be associated with intention or kinetic tremor
What are some walking problems associated with ataxia?
may have problems walking or standing
broad based gait - to counter imbalance
may lift legs to high when walkin
what is titubation?
abnormal tremors of the body or head
looks like a rocking motion of trunk or head can be rocking to side to side or forward and back or in a rotary motion
what two types of abnormal eye movements can be seen in ataxia?
nysgtagmus
oculodysmetria
what is nysgtagmus?
it is the jerking back and forth of the eyes at rest
what is oculodysmetria?
rapid eye movements as the ptnt tries to fix eyes on a visual target
what is hypotonia?
it is also found in LMN disorders
-can be associated with excessive pendulousness (if arm swings freely it continues for a long period of time than normal)
-this is due to decreased resistance to movement
also can have impaired check and excessive rebound-when arm is outstretched with eyes shit and a light tap is given on wrist this results in a large displacement of the arm followed by overshooting of original position when arm returns
What is dysmetria?
person is not able to control the range of movement and is seen typically by over or undershooting a target
What is dysdiadochokinesis?
it is decomposition of movement occurring in cerebellar problems
- it results in errors in sequence and speed of the component parts of movement (produces incoordination)
- an be assessed by having ptnt move tongue side to side wiggling and patting floor with ball of foot (these are analogous to speech AMR’s)
What is ataxia the product of?
dysmetria and dysdiadochokinesis
Ataxic movements are:
halting, imprecise, jerky, poorly coordinated, lacking in speed and fluidity
What are cerebellar disorders often associated with?
intention or kinetic tremor
what is an intention or kinetic tremor?
seen in movement but sometimes in sustained postures.
tremor usually worsens when the person gets closer to the target
What are the non-speech clinical findings af ataxic dys?
oral mech exam is ok usually
gag reflex is usually normal
no pathological reflexes
and drooling is not common
what are the speech findings of ataxic dys?
have the ptnt do amr’s, reading, conversational speech
-do repetition of sentences with multisyllabic words– may result in distinctive irregular articulatory breakdowns and prosodic abnormalities
Primary problem with ataxic dys is with what subsystems?
artic and prosody
T or F. You rarely see problems with resonance in ataxic dys.
True
What are the best distinguishing features of ataxic dys (speech)?
look for telescoping (collapsing of syllables) excess and equal stress excess loudness variations dysprosody vowel distortions
are amr’s regular or irregular in ataxic dys?
irregular
