Lecture 16: Subcortical Dementias

cortex = __ matter

grey

subcortex = __ matter

white

what is grey matter

cell bodies

what is white matter

myelinated axons

most common subcortical dementia

PD

five structures in basal ganglia

caudate nucleus, putamen, globus pallidus, subthalamic nucleus, substantia nigra

which structures make up the striatum

caudate nucleus, putamen

one of the basal ganglia structures

caudate nucleus

one of the basal ganglia structures

putamen

one of the basal ganglia structures

globus pallidus

one of the basal ganglia structures

substantia nigra

one of the basal ganglia structures

subthalamic nucleus

one of the striatum structures

caudate nucleus

one of the striatum structures

putamen

basal ganglia main function

motor control

what NT is impaired in PD

dopamine

which structure is impaired in PD

substantia nigra

relationship between the specific NT and structure with PD

substantia nigra produces dopamine and sends it to other basal ganglia structures; dopamine deficit causes PD

primary motor signs of PD

• gait instability (impaired righting reflex, stooped posture)

• rigidity

• tremor

• bradykinesia

what kind of tremor with PD

pill-rolling tremor

what kind of tremor is pill-rolling

resting

what is a resting tremor

most prominent at rest; diminishes during action

T/F: pill-rolling tremor occurs at a random rate

false

bradykinesia

slow movement

T/F: symptoms of PD don’t show until majority of the substantia nigra cells have died

true

T/F: PD is caused by the substantia nigra damage itself, not the dopamine deficiency

false

less dopamine =

less movement

righting reflex

innate and automatic response that helps us stay upright when displaced from our normal position

some cognitive symptoms of PD

• bradyphrenia

• visualspatial deficits

• executive dysfunctioning

• hypophonia

• memory issues: problems with encoding and recall

which type of dementia (subcortical or cortical) is associated with aphasia, anomia, agnosia, etc

cortical

which type of dementia (subcortical or cortical) is least associated with memory impairments

subcortical

bradyphrenia

slow thinking

micrographia

using a small portion of the page

medications for PD

L-dopa, anticholinergics

what is L-dopa

dopamine precursor; helps increase dopamine levels

why do we not give people with PD pure dopamine

dopamine is too large to pass through the blood-brain barrier

side effect of L-dopa

dyskinesia

dyskinesia

abnormal movement

what symptoms does L-dopa aim to stop

tremor, freezing

what do anticholinergics do

block Ach

what symptom does anticholinergics aim to stop

rigidity

pallidotomy

kills cells in globus pallidus

thalotomoy

kills cells in thalamus

deep brain stimulation is effective for which symptoms

tremor, gait, etc

chorea

rhythmic dance-like movements

HD is definitely caused by __

genetics

age of diagnosis is relatively earlier for which dementia

HD

if one parent has HD, what are the odds the child will have HD

50%

what chromosome is associated with HD

4

what gene is associated with HD

CAG

100% will have HD if you have more than __ CAG repeats

42

more CAG repeats =

HD develops earlier

main structure affected by HD

caudate nucleus

HD motor symptoms

• chorea

• bradykinesia

• rigidity

• dystonia

dystonia

abnormal muscle tone

HD psychiatric symptoms

• depression

• psychosis

• OCD

HD cognitive symptoms

• bradyphrenia

• memory impairment: retrieval difficulties (recall is bad)

• executive impairment

  • verbal fluency

  • attention

  • memory

  • shifting strategies

  • planning

  • visuospatial abilities

PSP stands for

progressive supranuclear palsy

PSP is commonly misdiagnosed as ___

PD

why is PSP commonly misdiagnosed

similar symptoms to PD

tau misfolding is associated with __

AD, HD, PSP

brain areas impaired in PSP

• subthalamic nucleus

• substantia nigra

• superior colliculus

• striatum

hallmark motor symptom of PSP

downward gaze abnormalities

dysarthria

abnormal motor aspects of speech (moving tongue, lips, etc)

PSP or PD: executive functioning is more impaired

PSP

utilization behavior

using things when not appropriate (using someone else’s pen)

T/F: there is aphasia with PSP

false

hallmark structural sign of PSP

penguin sign

why does the penguin sign occur

brain tissue in midbrain has atrophied, becoming very thin

penguin sign is associated with which dementia

PSP

T/F: PSP has weak response to drug treatment

true

if the patient responds to L-dopa, they are likely to have

PD

CJD brain structure

sponge-like holes

which dementia has an extremely rapid progression

CJD

difference between normal and variant CJD for brain imaging

pattern seen in EEG with normal CJD patients is not present in variable CJD patients

hallmark motor signs of CJD

myoclonus, extreme startle reflex

myoclonus

involuntary twitching/jerking

ataxia

loss of coordination and balance, leading to clumsy, jerky movements

apraxia

inability to plan or execute learned movements, even with intact muscle strength and coordination

akinesia

lack of spontaneous movement

akathesia

inability to remain still

types of extrapyramidal dysfunction

akinesia, akathesia

extrapyramidal dysfunction is associated with which dementia

CJD

CJD hallmark cognitive symptom

episodic unresponsiveness

episodic unresponsiveness

blanking out (like an absence seizure)

T/F: CJD is treatable

false

DLB symptoms

• hallucinations, delusions

• fluctuations in alertness (like CJD)

• Parkinsonism (rigidity, slowing, gait)

Lewy bodies

spherical inclusions found in cytoplasm

where are Lewy bodies in PD

brainstem

where are Lewy bodies in DLB

everywhere

other than DLB, which dementia has Lewy bodies

PD

other than Lewy bodies, what other brain changes do DLB patients have

misfolded tau proteins

key features necessary for DLB (must meet 2/3 conditions)

1. fluctuating attention/alertness

2. visual hallucinations

3. motor features of parkinsonism

T/F: memory is not impaired in DLB

true

which domain is interestingly not impaired with DLB

memory

cortical vs subcortical: language in cortical

aphasia

cortical vs subcortical: language in subcortical

no aphasia

cortical vs subcortical: memory in cortical

recall =(ish) recognition. basically, can’t store new memories

cortical vs subcortical: memory in subcortical

recall < recognition. impaired more, since it affects frontal lobes

cortical vs subcortical: visuospatial in cortical

equally impaired