Functional Neurologic Disorder (FND) Flashcards
how does Mayo Clinic define FND
neuro sx that can’t be explained by a neuro dz or other medical condition
pt demonstrates physical sx w/o organic cause
FND is considered a condition at the intersection of what 2 healthcare practices
neurology
psychiatry
“neuropsychiatric” disorder
what are risk factors for FND
females > males
anxiety disorders
possible psych trauma
what are the 3 main reasons to change the name from conversion disorder to FND
new dx criteria
dx of inclusion - tests to be used
look at fMRI evidence
conversion disorder vs FND
conversion disorder:
- dx of exclusion
- direct result of trauma (physical or psych)
- no physio theory or evidence behind dx
FND:
- dx of inclusion
- may have a “trigger”
- fMRI evidence
- “secondary gain” - pt gets something (+) out of being sick
what are 3 subsets of FND
nonepileptic sz
functional weakness
functional mvmt disorders
what are examples of the nonepileptic sz subset of FND
pseudo sz
functional
sz sx without any electrical correlate in EEG
what are 2 types seen in the functional weakness subset of FND
inconsistent weakness
paralysis
what are 3 types seen in the functional mvmt disorders subset of FND
functional tremor
- more common in adults
functional gait disorder
- more common in kids
functional coma
which 3 structures are altered in FND when viewed w an fMRI
insula
amygdala
dorsal prefrontal cortex
how does someone w FND’s insula look different on a fMRI and what does this mean
dec volume in R and L insula
R insula dec connectivity w:
- R temp/parietal junction
- R sensorimotor cortex
- (B) supplementary motor area
= dec connectivity to things that plan, execute, and monitor motor output
how does someone w FND’s amygdala look different on a fMRI and what does this mean
inc volume of amygdala
- amygdala = emotional stability, forming emotional memories
inc connectivity to motor cortex
- see motor output disturbances
how does someone w FND’s dorsal prefrontal cortex look different on a fMRI and what does this mean
dec dorsal prefrontal cortex when performing motor task
-> dec ability to respond flexibly to tasks and adjustments
-> dec agency
what is agency and why is it significant that this is dec in FND
agency is knowing you are the cause of whatever mvmts and consequences
d/t dec in dorsal prefrontal cortex activity, there is dec agency in FND
–> connectivity is missing
–> if moved passively, motor cortex tells them they did it themselves
–> when moved actively, brain tells them someone else did it
overall the changes seen on a fMRI lends to what physio characteristics of FND
regulating emotions
processing emotions
planning and acknowledging voluntary mvmts
what needs to be done first in the process of dx FND
r/o organic dx
- get some imaging!!
what steps are involved in r/o an organic dx
appropriate imaging
appropriate blood tests
possible spinal tap
EMG
EEG
before going into the eval, what do you need to find out from the team
what they have told the pt and family
- did they hear the dx and how was it explained
what tests have been completed and which tests are currently ordered to be performed
what are 4 steps to r/i a FND dx
hx
physical exam - impairments
functional skill assessment
specific test pertaining to hypothesis of FND dx
what are components to their hx that you might start to r/i FND
abrupt onset
intermittent spontaneous cure or remission
secondary gain
psychiatric comorbidities
what is an important thing to consider if someone has psychiatric comorbidities
this shouldn’t have more weight than anything else in their hx
what are components looked at in a physical exam for FND
strength
sensory testing
coordination
gait
functional mobility
special tests
how is motor control assessed in FND
MMT
observational analysis
Hoover’s sign
how will MMT present in FND
give way weakness
- cuts off any motor engagement
