The document discusses apraxia, a disorder characterized by the inability to perform learned movements despite having intact sensory and motor function. It outlines various types of apraxia, their clinical manifestations, and the role of the parietal cortex in motor control. Additionally, it highlights the significance of mirror neurons and presents clinical tests for diagnosing apraxia.

1. ‫در‬ ‫شده‬ ‫ارائه‬:
‫آپراکسی‬ ‫و‬ ‫تقلید‬ ‫تخصصی‬ ‫کارگاه‬:
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‫دیماه‬96

2. Apraxia: A Disorder of Motor Control
 apraxia can be defined as a disturbance of the
mental control of deliberate motor actions
 Apraxia is a disturbance of goal-directed motor
behavior characterized by an inability to perform
previously learned movements in the absence of
weakness or sensory defects
 Intact perception, attention, coordination,
motivation, and comprehension

3. Clinical manifestations of Apraxia
 limb or the mouth and face
 may be unable to move with
◦ imitation
◦ verbal command
◦ or both
 often associated with deficits of more complex movements
◦ gestures,
◦ pantomime,
◦ sequential movement

4. Clinical manifestations of Apraxia
 There may be failure
◦ to perform a movement in response to an object
◦ failure to handle an object correctly
 Motor errors vary in severity, ranging from
◦ inability to generate any appropriate movement
◦ mild clumsiness in generating a complex movement

5.  In the late nineteenth century three syndromes
characterized by wrong or awkward actions in spite
of preserved motor strength and coordination:
◦ mind-palsy,
◦ asymbolia,
◦ apraxia

6. Dorsal and Ventral systems of the cerebral cortex

7. Parietal cortex
 parietal cortex plays a key role in the
◦ visual guidance of motor behavior
◦ spatial perception
◦ cognition
◦ understanding where objects are relative to each other
 Parietal cortex developed the capacity to represent
◦ where things are relative to the body to guide actions such as
grasping,
◦ and then developed the ability to represent where things are
relative to each other without reference to the body

8. injury to the parietal cortex
 first category are impairments of
◦ body awareness,
◦ motor control,
◦ visual guidance of motor behavior
 These deficits result from damage to dorsal parts of the parietal
cortex close to and connected with the somatosensory cortex
 Asomatognosia(deny the existence of the arm or leg contralateral to the lesion)
 Apraxia
 optic ataxia(difficulty reaching for an object in the peripheral visual field as when
reaching for a coffee cup while readli1gthe newspaper)

10. injury to the parietal cortex
 second category are impairments of
◦ spatial perception
◦ cognition
 These deficits result from damage to ventral parts of
parietal cortex close to and connected with the
visual cortex
 hemi spatial neglect
 constructional apraxia

13. Mind-palsy
 The concept of mind-palsy was based on an
associationist model of brain organization
 mind-blindness, mind-deafness, and mind-
numbness
 By analogy, a loss of motor memories should result
in “mind-palsy

14. Asymbolia
 Finkelnburg concluded that the term “aphasia” was ill-
chosen
 “a pathological disturbance of function where the
ability to understand or express concepts by means of
learned signs is partially or completely abolished.”
 Motor asymbolia
◦ selective asymbolia affecting memory images of motor
actions

15. Apraxia
 First time German linguist Chaim Steinthal
distinguished apraxia from asymbolia ( 1871 )
 aphasia, is not a unitary disorder but a combination of
preserved and disturbed verbal and non-verbal
capabilities
 an aphasic composer who wrote notes awkwardly,
placing the head of quarter-notes to the right instead
of the left side of the stem

16. Apraxia
 This apraxia is an obvious amplification of aphasia
 In another direction aphasia extends to a general
inability to comprehend sign, asemia.

18. Classification of apraxia
 selective damage gives rise to three syndromes: (1)
posterior parieto-occipitial lesions interfere with
generation of the movement formula and cause “the
localizable component” of ideational apraxia;
 (2) inability to transform the movement formula into
motor innervations is the core of ideo-kinetic apraxia;
 (3) loss of kinetic memory results in limb-kinetic apraxia

19. Classification of apraxia
 Ideational apraxia
◦ gross misuse of single tools and objects
◦ patient grasped scissors correctly but tried first to brush and then to
write with them
◦ Another patient used a piece of bread for wiping his eyes
◦ knowledge about the correct use of objects
◦ Recognition of the pragmatic significance of objects can be lost
although recognition of other aspects of the object is preserved.
 ideo-motor apraxia
 Ideational apraxia is a disorder of the mind
 ideo-motor apraxia of the body

20. ideo-motor apraxia
 They produced hesitant, awkward, and spatially
wrong movements when asked to produce
◦ emblematic gestures (e.g., beckoning, making a military
salute)
◦ Pantomimes of tool use (e.g., demonstrating the use of
scissors)
◦ to touch distinct body parts (e.g., putting the index on the
nose).
◦ Use of objects was somewhat clumsy but with few
exceptions ultimately successful

21. Classifing cation of apraxia
 Limb-kinetic apraxia
◦ We find a slowing and stiffness of movements,
◦ a difficulty of isolated movements
◦ a tendency to synergistic and associated movements
◦ a particularly severe loss of fine graded and structured movements
◦ The simultaneous as well as the sequential coordination of single
movements is disturbed
◦ The higher the demands on innervatory combinations, the more severe
are the deficits of manual skills
◦ By contrast, actions like clapping hands, praying, catching a fly, which
are less finely tuned, are successful

24. Callosal apraxia
 He had no aphasia
 but was completely unable to write, to copy letters, or
to compose words from anagram letters with the left
hand
 The left hand was skillful for everyday actions like
buttoning, eating, or drinking from a glass,
 but committed gross errors when confronted with less
routine tasks

25. Callosal apraxia
 when a pince-nez was handed to him, he:
◦ brought it to the mouth,
◦ sticked out the tongue and tried to put the pince-nez on
the rolled up tongue
 Given a matchbox and asked to light a match,
◦ he brought the box to the mouth,
◦ took out two matches with the tongue,
◦ put one of them on the table,
◦ and kept the other in the mouth as if it were a cigar (
Liepmann & Maas, 1907 , p. 217).

26. Callosal apraxia
 Post-mortem examination displayed two lesions
◦ One was in the brainstem
◦ Other destroyed the anterior and middle portion of the
corpus callosum
 Liepmann referred
◦ the paresis of the right limbs to the brainstem focus
◦ reasoned that agraphia and apraxia of the left hand were
due to calossal disconnection depriving the right-sided
motor cortex from its connections to the left hemisphere

28. Constructional apraxia
 a temporary lodger in the house of apraxia
 optic apraxia

29.  Liepmann’s model of apraxia included three
domains of actions:
◦ use of tools and objects,
◦ performance of communicative gestures,
◦ imitation of gestures

31. Imitation and mirror neurons
 the route from visual perception to motor
replication of gestures can be direct
 it bypasses recognition of the meaning of the
gesture
 “mirror neurons
◦ active when the monkey sees another monkey or a
human perform an action and when it performs the
same actions.

32. Imitation and mirror neurons
 the putative human direct route accommodates novel
and meaningless gestures,
 mirror neurons in monkey react only to biologically
meaningful and familiar actions

33. Clinical tests for apraxia
 simple verbal commands such as “look upward” or
“close the eyes.” Commands for whole-body
movements such as “stand up” or “turn around”
 examine limb, buccofacial, andaxial body
movements separately

34. Clinical tests for apraxia
 Imitation of familiar movements or gestures across
these same body segments
 Imitation of meaningless gestures
 generate transitive movements, i.e., the
manipulation of objects
◦ “show me how you brush your hair,”
◦ “how you blow out a candle,”
◦ “pretend to throw a ball.”

35. Ten hand postures used for testing imitation of meaningless
gestures

36. Ten finger postures used for testing imitation of meaningless
gestures

37. Ten foot postures used for testing imitation of meaningless
gestures

41. Speech apraxia
 difficulty with phoneme sequencing,
 inconsistent errors,
 groping for sounds,
 Difficulty imitating oral movements,
 Difficulty imitating sounds and words,
 atypical stress and intonation patterns
 CAS is estimated to occur in approximately one to
two children per thousand (ASHA, 2015).

47. P.R.I.S.M. foundation to treating childhood
apraxia of speech

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