Disconnective Syndromes

Question 1

What is a node ?

Answer 1

A group of neurons which cluster. They will interact to create a module.

Question 2

What is a module ?

Answer 2

Nodes with larger connectivity degree. Through their interaction they create an output which will be sent to the main module : the hub.

Question 3

What is a hub ?

Answer 3

A module that connects to other modules.

Question 4

Which interaction is responsible for prospection ?

Answer 4

The mPFC - acc interaction. Reasoning on what to do and establishing all possible scenarios. It’s an unconscious process.

Question 5

What is the default mode network ?

Answer 5

It is a large scale brain network primarily composed of the dmPFC, pCC, precuneus and angular gyrus. It is active when a person is not focused on the outside world and the brain is at wakeful rest (such as daydreamin). It can also be active during detailed thoughts related to external task performance. It is active when the individual is thinking about others, about themselves, remembering the past and planning for the future.

Question 6

What is the function of the frontoparietal network ?

Answer 6

Creating mental images of everything to extrapolate all possible outcomes to decide on the behavioral response. It is a large scale brain network composed of dlPFC, posterior parietal cortex, intraparietal sulcus. It is involved in sustained attention, complex problem-solving and working memory.

Question 7

What is the function of the salience network ?

Answer 7

Gathering and interpretation of external stimuli, as body sensation (internal) leading to reactions and adaptations to sensory experiences. These adaptations can influence perception and cognition, directly impacting planning and decision making process.

Question 8

Define apraxia and list the movements involved.

Answer 8

It is a disconnection disorder which cannot be explained by: muscle weakness, dyskinetic disorders, abnormal tone or posture, intellectual or communication deficit, non-cooperation. It is most observed in left brain damage. It is a disturbance of skilled movements which can involve:
- imitation
- gesticulation for communication
- too selection and use
- sequential movements

Question 9

What is the Liepman model ?

Answer 9

Describes dyspraxia as a disturbance on one of two phases:
1) creation of a mental image of the movement in space considering body proportions and sensations. = ideational dyspraxia
2) transduction of an idea of a movement to appropriate mechanical commands. = ideomotor dyspraxia.

Question 10

Which network is affected in case of ideomotor dyspraxia ?

Answer 10

Default mode network

Question 11

What will cause a damage in the anterior default mode network ?

Answer 11

Difficulty translating a mental image into an intended motor action. Part of ideomotor dyspraxia.

Question 12

What will cause a damage to the left default mode network ?

Question 13

What are the forms of dyspraxia ?

Answer 13

• ideomotor
• ideational
• limb-kinetic
• conceptual
• dissociative
• conduction

Question 14

What is ideomotor dyspraxia ?

Answer 14

Deficit in pantomime of tool use and meaningless gesture, without loss of knowledge of the task.

Question 15

What is ideational dyspraxia?

Answer 15

Deficit in tool use and sequential tasks.

Question 16

What is lim-kinetic dyspraxia ?

Answer 16

Manipulative deficit, similar to a loss of dexterity on the contralateral limb

Question 17

What is conceptual dyspraxia ?

Answer 17

Knowledge deficit about the selection of tools and objects for a task. Ex: patient cannot recognize an object in front of them but can describe it and its use. Connection between action and tool semantics is damaged.

Question 18

What is dissociative dyspraxia ?

Answer 18

Deficit following verbal command. Patient can perform the task if it’s written.

Question 19

What is conduction dyspraxia?

Answer 19

Deficit on gesture imitation only.

Question 20

How to evaluate dyspraxia ?

Answer 20

• imitation of meaningless gesture
• communicative (meaningful) gestures
• tool and object use

Question 21

What is asymbolia ?

Answer 21

It’s the “clumsiness” of communicative gestures.

Question 22

How to ensure that tool use is properly assessed ?

Answer 22

• patient must have frequently used the tool and be familiar with it
• relationship between tool structure and function must be quite obvious
• diadochokinetic use

Question 23

What are the strategies used to “treat” dyspraxia ?

Answer 23

• strategy training
• sensory stimulation
• cueing
• chaining

Question 24

What is strategy training ?

Answer 24

Use of compensatory mechanism to facilitate ADLs. Based on internal or external process:
- mentally describe the action
- making use of assistive technology

Question 25

What is sensory stimulation strategy ?

Answer 25

Applying direct or indirect augmented sensory input:
- upplying pressure
- utilizing different surface stimulation
- weight bearing during exercise
- give patient a positive feedback when task is successful

Question 26

What is chaining strategy ?

Answer 26

Break down of task is small steps. 5 to 6 steps maximum.

Question 27

What are the executive faculties ?

Answer 27

• attention
• working memory
• self control
• inhibitory control

Question 28

What are the impaired faculties in ideomotor - parietal dyspraxia ?

Answer 28

• pantomime
• imitation
• meaningful communicative gesture
• transitive movements may be impaired or present

Question 29

What are the impaired faculties in ideomotor - disconnective dyspraxia ?

Answer 29

• pantomime
• imitation
• transitive movements may be impaired or present

Question 30

What are the functions impaired in dissociative dyspraxia ?

Answer 30

• pantomime
• sequential actions

Question 31

What are the functions impaired in ideational dyspraxia ?

Answer 31

• sequential actions
• tool use may be impaired or present
• transitive movement may be impaired or absent

Question 32

What are the functions impaired in conceptual dyspraxia ?

Answer 32

• pantomime
• sequential actions
• tool use
• transitive movement

Question 33

What are the functions impaired in limb-kinetic dyspraxia ?

Answer 33

• limb-kinetic movement
• transitive movements mays be impaired or present

Question 34

What is the role of SMA ?

Answer 34

Shot term procedural memory