Dementia with Lewy Bodies (DLB) neuropathological feature
- lewy bodies throughout cortex, paralimbic areas, and substantia nigra (like PD)
- Senile plaques but less neurofibrillary tangles
Dementia with Lewy Bodies neuronal degeneration regions
- frontal, anterior cingulate, insular, temporal areas
- generalized atrophy but with less medial temporal lobe atrophy than in AD
- more frequent occipital hypoperfusion than in AD
- Abnormal EEG with greater temporal slowing and transient slow wave activity than in AD
Dementia with Lewy Bodies sensory sx
- Extrapyramidal like Parkinson’s in >50%: bradykinesia, rigidity, hypophonic speech, masked facies, stooped posture, slow shuffling gait
- Sensory function intact
DLB cognition
- Visuoperceptual deficits prominent (visual search, size/form discrimination, id of fragmented letters, overlapping figures
- Poor visuoconstruction
- Poor clock drawing and no improvement with copying clock (unlike AD and PD)
- fluctuating attn and lucidity within minutes or weeks/months
- transient confusional states
- impairment on vigilance tests, tests of sustained/selective/divided attn
- impaired abstract reasoning
DLB memory
- early on preserved medial temporal lobe
- preserved consolidation and storage of verbal info but poor retrieval
- Assessment of visual memory is nearly impossible because visuoperceptual processing is so impaired
DLB language
- Similar to AD
- Letter and semantic fluency decreased
- Naming ability affected due to visualperceptual rather than semantic errors
DLB EF
- Similar to AD
- Difficulty engaging or shifting, perseverative
- Failures on conflict tasks
DLB Psychiatric
- Depression in 50%
- Hallucinations (usually visual) can appear early
- Have insight into unreality of hallucinatins
- Paranoid delusions
- Inappropriate treatment with neuroleptics can result in severe nonreversible motor dysfunction and exacerbate parkinsonian symptoms
DLB Sleep
-REM sleep disorder common
DLB treatment
- Improved cognition and behavior from cholinesterase inhibitors
- levadopa helps with motor
- SSRIs and SNRIs for depression
- Atypical antipsychotics for hallucinations, delusions, and behavioral disturbances
Subcortical dementias sx
1) cognitive slowing (bradyphrenia) with disturbances of attention, EF, visuospatial abnormalities, and memory disorder affecting retrieval more than learning 2) absence of aphasia, apraxia, agnosia (those are cortical) 3) emotional or psychiatric features of apathy, depression, or personality changes
Clinical distinction b/w cortical & subcortical dementals
- Behavioral distinctions mostly in earlier stages of disease
- Cortical degeneration: language abilities, reasoning, problem solving, learning, and praxis as INSTRUMENTAL functions
- Subcortical: FUNDAMENTAL functions crucial to survival: arousal, attention, processing speed, motivation, emotionality
Subcortical dementia etiologies
- Disorders of basal ganglia and subcortical vascular, infectious, inflammatory, neoplastic, and traumatic conditions
- Mostly extrapyramidal motor system (movement disorders)
Cortical dementias names
AD, Frontotemporal Lobar Degeneration (FTD), Semantic Dementia
-(DLB is neither cortical nor subcortical)
Subcortical dementias names
HD, PD
Subcortical dementia systems
-Basal ganglia (Caudate, putamen, globus pallidus), subthalamic nucleus, substantia nigra, and interconnections to each other and to thalamic nuclei
