Podcast
Questions and Answers
Which of the following statements about the basal ganglia pathways is correct?
Which of the following statements about the basal ganglia pathways is correct?
- The indirect pathway is primarily activated through D1 receptors.
- The subthalamus is an inhibitory nucleus in the basal ganglia.
- The striatum receives excitatory input from the cortex. (correct)
- All output from the cortex goes to GPi.
The nigrostriatal pathway activates the indirect pathway through D2 receptors.
The nigrostriatal pathway activates the indirect pathway through D2 receptors.
False (B)
What condition is characterized by degeneration of the nigrostriatal pathway?
What condition is characterized by degeneration of the nigrostriatal pathway?
Parkinson's disease
A common symptom of Parkinson's disease includes _____ of movement.
A common symptom of Parkinson's disease includes _____ of movement.
What is the most common type of Frontotemporal Dementia?
What is the most common type of Frontotemporal Dementia?
Match the following terms to their respective features:
Match the following terms to their respective features:
Diffuse Lewy Body Dementia is the most common cause of dementia.
Diffuse Lewy Body Dementia is the most common cause of dementia.
What is the age of onset for Frontotemporal Dementia?
What is the age of onset for Frontotemporal Dementia?
Involves the MAPT gene on chromosome ______.
Involves the MAPT gene on chromosome ______.
Match the following types of dementia with their characteristics:
Match the following types of dementia with their characteristics:
What is the main genetic mutation associated with CADASIL?
What is the main genetic mutation associated with CADASIL?
Normal Pressure Hydrocephalus (NPH) is characterized by ventriculomegaly without atrophy.
Normal Pressure Hydrocephalus (NPH) is characterized by ventriculomegaly without atrophy.
List one common clinical feature of Normal Pressure Hydrocephalus.
List one common clinical feature of Normal Pressure Hydrocephalus.
The most common inherited vascular dementia is ______.
The most common inherited vascular dementia is ______.
Match the following features with their corresponding condition:
Match the following features with their corresponding condition:
Which of the following nuclei is NOT part of the Basal Ganglia?
Which of the following nuclei is NOT part of the Basal Ganglia?
The Basal Ganglia are exclusively responsible for cognitive activities.
The Basal Ganglia are exclusively responsible for cognitive activities.
Name one function of the Basal Ganglia.
Name one function of the Basal Ganglia.
The _____ nucleus is known to have an internal and external section in the Basal Ganglia.
The _____ nucleus is known to have an internal and external section in the Basal Ganglia.
Match the following functions with the appropriate components of the Basal Ganglia:
Match the following functions with the appropriate components of the Basal Ganglia:
What is a key characteristic of cognitive impairment in Dementia with Lewy Bodies (DLB)?
What is a key characteristic of cognitive impairment in Dementia with Lewy Bodies (DLB)?
In Parkinson's disease, visual hallucinations and fluctuating alertness are common symptoms.
In Parkinson's disease, visual hallucinations and fluctuating alertness are common symptoms.
What substance is primarily found in Lewy Bodies?
What substance is primarily found in Lewy Bodies?
A common effect of antipsychotic treatment in Dementia with Lewy Bodies is that it _____ symptoms.
A common effect of antipsychotic treatment in Dementia with Lewy Bodies is that it _____ symptoms.
Match the following symptoms with their corresponding condition:
Match the following symptoms with their corresponding condition:
What is the most significant risk factor for Binswanger Disease?
What is the most significant risk factor for Binswanger Disease?
Cerebral Amyloid Angiopathy is characterized by Aβ40 protein deposition and is commonly seen in the elderly.
Cerebral Amyloid Angiopathy is characterized by Aβ40 protein deposition and is commonly seen in the elderly.
What type of infarct is associated with Binswanger Disease?
What type of infarct is associated with Binswanger Disease?
Within 3 months of a stroke, the onset of _____ is often observed.
Within 3 months of a stroke, the onset of _____ is often observed.
Match the clinical features with the affected fibres in Binswanger Disease:
Match the clinical features with the affected fibres in Binswanger Disease:
Which type of dementia is characterized by spongiform changes in the cerebral cortex?
Which type of dementia is characterized by spongiform changes in the cerebral cortex?
Rapidly progressive dementia is a common feature of prion diseases.
Rapidly progressive dementia is a common feature of prion diseases.
What protein is associated with Creutzfeldt-Jakob disease?
What protein is associated with Creutzfeldt-Jakob disease?
In large vessel disease, the most common infarct site is the __________ PCA lesion.
In large vessel disease, the most common infarct site is the __________ PCA lesion.
Match the type of dementia with its associated protein:
Match the type of dementia with its associated protein:
Which type of rigidity is characterized by both rigidity and tremor at the wrist in Parkinson's Disease?
Which type of rigidity is characterized by both rigidity and tremor at the wrist in Parkinson's Disease?
Patients with Parkinson's Disease typically exhibit increased blinking.
Patients with Parkinson's Disease typically exhibit increased blinking.
What gait pattern is described as narrow-based with short quick steps and freezing in between?
What gait pattern is described as narrow-based with short quick steps and freezing in between?
In Parkinson's Disease, the absence of the ______ sign on an MRI may indicate certain changes in the midbrain.
In Parkinson's Disease, the absence of the ______ sign on an MRI may indicate certain changes in the midbrain.
Match the symptoms of Parkinson's Disease with their descriptions:
Match the symptoms of Parkinson's Disease with their descriptions:
Which type of dementia is characterized by severe memory impairment and normal cognitive & motor speed?
Which type of dementia is characterized by severe memory impairment and normal cognitive & motor speed?
Cortical dementia is associated with highly impaired coordination.
Cortical dementia is associated with highly impaired coordination.
Name one example of a subcortical dementia.
Name one example of a subcortical dementia.
In cortical dementia, the affected regions include the ______ ganglia.
In cortical dementia, the affected regions include the ______ ganglia.
Match the following symptoms to their corresponding type of dementia:
Match the following symptoms to their corresponding type of dementia:
Which of the following symptoms is less severe in cortical dementia compared to subcortical dementia?
Which of the following symptoms is less severe in cortical dementia compared to subcortical dementia?
Agnosia is a common symptom of both subcortical and cortical dementia.
Agnosia is a common symptom of both subcortical and cortical dementia.
The primary pathology in prion diseases involves the formation of ______ proteins.
The primary pathology in prion diseases involves the formation of ______ proteins.
What type of tremor is predominantly seen in Parkinson's disease?
What type of tremor is predominantly seen in Parkinson's disease?
Essential tremor is usually asymmetric in its distribution.
Essential tremor is usually asymmetric in its distribution.
What medication class is typically used to alleviate tremors in Parkinson's disease?
What medication class is typically used to alleviate tremors in Parkinson's disease?
In essential tremor, writing is typically characterized as _____ and tremulous.
In essential tremor, writing is typically characterized as _____ and tremulous.
Match the following characteristics to either Parkinson's disease tremor or essential tremor:
Match the following characteristics to either Parkinson's disease tremor or essential tremor:
Study Notes
Frontotemporal Dementia (Pick's Disease)
- Occurs in 70% of cases spontaneously
- Onset typically occurs between 50-60 years old
- Characterised by rapid progression
- Pathology involves the MAPT gene on chromosome 17
- Protein Tau becomes hyperphosphorylated
- Other proteins associated with the disease are Fus
- Bilateral atrophy of the prefrontal cortex
- Most common type is Behavioural Variant
- Symptoms include Loss of Social Embarrassment, Dysfunction of Social and Emotional Systems
- Apathy, Overeating, Impaired Planning and Judgement also frequently occur
- Memory is relatively preserved
- Temporar lobe involvement results in Increased Oral Behavior
- Hyperphosphorylated Tau is a characteristic of both Alzheimer's and Pick's disease
Diffuse Lewy Body Dementia
- Second most common cause of Dementia
- Associated with Parkinson-Plus and Atypical Parkinson's Syndrome
- Parkinson-Plus syndrome involves "Tau"pathies, specifically Progressive supranuclear palsy, Corticobasal degeneration
- "a synuclein'-opathies like Multiple system atrophy and Diffuse Lewy Body dementia are also linked
- Diagnosis may be related to the presence of certain proteins in the brain
- Time Stamps of the video on this topic are 00:00:27 and 00:07:10
Direct and Indirect Pathways
- All input from the Cortex to the Striatum
- All output goes through the Globus Pallidus Internal (GPi)
- The Subthalamus is the only excitatory nucleus in the Basal Ganglia
- The Nigrostriatal Pathway connects the Substantia Nigra (SN) to the Corpus Striatum
- Via D1 receptors, the direct pathway is activated
- The indirect pathway is inhibited via D2 receptors
CADASIL
- Cerebral autosomal dominant arteriopathy with small vessel ischemic changes, leukoencephalopathy
- Also referred to as CADASIL with stroke and ischemic leukoencephalopathy
- Most common inherited vascular dementia
- Characterized by a NOTCH 3 mutation
- Presentation includes aura + migraine + dementia + stroke
Normal Pressure Hydrocephalus (NPH)
Hydrocephalus
- Occlusive (Non-communicating) Hydrocephalus is caused by Aqueductal Stenosis
- Non-occlusive (Communicating) Hydrocephalus is caused by increased CSF production or decreased CSF absorption
NPH
- Obtuse interventricular angle denotes atrophy
- Characterised by an adsorption defect and outflow resistance of CSF, leading to Ventriculomegaly
- Atrophy does not occur
- Symptoms progress over weeks to months
- Gait apraxia (magnetic foot), urinary incontinence, and subcortical dementia are abnormalities commonly observed
- Normal CSF pressure (~20 ml/day produced)
- Treatment involves Shunting, with good prognosis if effective
NPH Etiology
- Most cases are idiopathic
- Other etiologies include: Familial, Congenital, and Acquired (Trauma, SAH)
Basal Ganglia (BG)
Gross Anatomy
- Includes the following nuclei:
- Caudate nucleus (CN)
- Putamen
- Globus Pallidus (GP)
- Subthalamic nucleus (STN)
- Substantia nigra (SN)
- Corpus Striatum
- Lenticular Nucleus
Physiology
- Functions include:
- Complex motor activity
- Initiation and scaling of movement
- Cognitive aspect of motor activity
- Activity set for movement (Planning, programming & initiation)
Common Features of Prion Diseases
- Young onset dementia
- Rapidly progressive dementia
- No immune response
- Examples include: Creutzfeldt-Jakob disease (CJD), Familial fatal insomnia, Kuru, Gerstmann-Straussler-Scheinker disease
CJD
- No immune response/inflammation
- Long incubation period
- Pathology reveals Spongiform changes in the cerebral cortex and Basal ganglia hyperintensities
- Symptoms include dementia + myoclonus
Investigations for CJD
- EEG shows low voltage background, high voltage sharp wave activity
- CSF is normal
- Brain biopsy is required for diagnosis confirmation
- Flupirtine maleate can be used as treatment (centrally acting non-opioid analgesic)
Vascular Dementia
- Large vessel disease (Post-CVA dementia) and small vessel disease
- Large vessel disease, most common infarct site is Bilateral Posterior Cerebral Artery (PCA) lesion
- Criteria include:
- Dementia
- Cerebrovascular disease, particularly multi-infarct state with "strategic territory" infarct (infarcts in areas that lead to dementia)
Lewy Bodies
- Intraneuronal cytoplasmic inclusions
- Composed of alpha-synuclein
- Alpha-synuclein-opathies
DLB Dementia vs Parkinson's Disease
- DLB Dementia
- Cognitive impairment precedes/ within 1 year of motor manifestations.
- Shows predominantly rapid progressive dementia.
- Visual hallucinations and fluctuating alertness precede onset of motor symptoms
- Tremors are uncommon
- Bilateral axial rigidity is present (Rocket sign +)
- Gait abnormalities are common
- Antipsychotics worsen symptoms (due to dopamine receptor inhibition)
- L-dopa does not improve symptoms
- No specific treatment available
- Parkinson's Disease
- Cognitive impairment occurs after 4–5 years of motor manifestations
- Visual hallucinations are common
- Tremors are common
- Rigidity is common
- Gait abnormalities are common but are asymmetrical
- Antipsychotics have uncommon effects
- L-dopa improves symptoms
- Treatment includes L-dopa, deep brain stimulation
- Falling immediately backward after attempting to get up from a chair is characteristic of both conditions.
Binswanger Disease
- Most important risk factor is Hypertension
- Characterized by Lacunar infarct
- Pathology involves Lipohyalinotic infarct affecting penetrating vessels (size: 30 - 300 μm)
- MRI shows White matter hyperintensities in elderly
Cerebral Amyloid Angiopathy
- Aβ40 protein deposition
- Found in elderly individuals
- Associated with Microhemorrhages
Relationship between Dementia and Stroke
- Onset of dementia within 3 months of stroke
- Stepwise decline in cognitive function
Clinical Features (Similar to Vascular Parkinson's)
- Corticobulbar tract involvement causes Pseudobulbar palsy, gait disturbances & falls, gait apraxia and the Magnetic/ignition foot phenomenon (feet "stuck" to floor)
- Corticospinal tract involvement (affects lower limb fibers close to the ventricle) causes Gait disturbances & falls, gait apraxia and the Magnetic/ignition foot phenomenon
- Fibers from the paracentral lobule are associated with Urinary abnormalities and Personality changes
- Corticostriate fibers (Fibres from PFC to striatum) are associated with Urinary abnormalities and Personality changes
Subcortical v/s Cortical Dementia
- Cortical Dementia
- Includes Alzheimer's and Frontotemporal dementia (FTD)
- Subcortical Dementia
- Includes Diffuse Lewy Body Dementia (DLB), Progressive Supranuclear Palsy (PSP), Normal Pressure Hydrocephalus (NPH), and Binswanger disease
Affected Regions
| Feature | Subcortical Dementia | Cortical Dementia |
|---|---|---|
| Affected regions | Hippocampus, medial temporal lobe | Basal ganglia; Thalamus; Subcortical white matter; Corticospinal fibres; Corticobulbar fibres |
Symptoms
| Symptom | Subcortical Dementia (Severity) | Cortical Dementia (Severity) |
|---|---|---|
| Memory Impairment | Severe (+) | Less severe (-) |
| Apraxia | Superior parietal lobe lesion | - |
| Agnosia | Association areas lesion | - |
| Acalculia | Angular gyrus lesion | - |
| Language | - | - |
| Visuo-spatial defect | - | - |
| Personality | Early dysphasia; more severe; indifferent | - |
| Mood | Depressed (Subcortical > Cortical) | - |
| Coordination | Normal | Impaired |
| Cognitive & motor speed | Normal | Slow |
| Abnormal movements | Rare | Common |
| Extrapyramidal symptom | - | - |
- Prion Diseases
- Prions are infectious proteins with no nucleic acid.
- Can be genetic or sporadic
- Pathology involves Beta-pleated PrPsc protein, leading to Spongiform degeneration of the cortex and Neuronal loss
Parkinson's Disease
Symptoms
- Hypertonia
- Two types: Cogwheel rigidity (rigidity + tremor) and lead pipe rigidity
- Froment's sign is activity-induced increase in contralateral rigidity
- Akinesia/Bradykinesia
- Bradyphrenia, reduced arm swinging, flexion hypertonia, short quick steps with freezing in between, festinant gait, micrographia, hypomimia, hypophonia, reduced blinking
- Glabellar tap sign is positive
- Atypical PD
- Bilateral axial rigidity, difficulty turning in bed/rising from a chair (wheelchair sign)
- Non-Parkinson's lesions with hypokinesia, specifically Hypothyroidism
- Postural Instability
- Unsteadiness and falls
- Pull test: Patient falls backward
Investigation
- Clinical diagnosis
- MRI:
- Hyperintensities bilaterally in grey matter surrounded by hypointense red nuclei and crural fibres at the midbrain level
- Swallow tail sign is absent (Swallow tail sign is present due to SN)
Additional Notes
- PD patients can also experience sensory symptoms (pain, anosmia), neuropsychiatric symptoms (depression > dementia), and gastrointestinal symptoms (dysphagia)
Comparison of Parkinson's Disease Tremor and Essential Tremor
| Characteristics | Parkinson's Disease Tremor | Essential Tremor |
|---|---|---|
| Tremor | At rest +/- reemergent tremor | Postural tremor |
| Frequency | 4-6 Hz | 5-12 Hz |
| Distribution | Asymmetric | Mostly symmetric |
| Body parts affected | Hands ± legs | Hands, head, voice |
| Writing | Small (micrographia) | Large and tremulous |
| Course | Progressive | Stable or slowly progressive |
| Family history | uncommon (1%) | Present |
| Extrapyramidal signs (bradykinesia, rigidity, and loss of postural reflex) | Present | Absent |
| Relieving factors | Levodopa, dopamine agonists, anticholinergics | Alcohol, propranolol, primidone, topiramate, gabapentin, clonazepam |
| Usual site for surgical treatment with deep brain stimulation | Subthalamic nucleus or globus pallidus interna | Ventral intermediate thalamus |
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Description
This quiz covers key features of Frontotemporal Dementia (Pick's Disease) and Diffuse Lewy Body Dementia. Learn about their symptoms, pathologies, and genetic associations. Test your knowledge on dementia types and their progression.
