Clinical Neuropsychology

1
Clinical Neuropsychology

• Aims and Objectives
• By the end of this lecture you will have learned
• The most common aims of a clinical
  neuropsychological assessment
• A brief review of the behavioural geography of
  the brain
• The types of patient most often seen by clinical
  neuropsychologists (e.g. the types of brain
  damage which typically cause neuropsychological
  deficits)
• Suggested reading
• Lezak, M (1995).Neuropsychological assessment.
  CH1, CH7
• Kolb Whishaw?

2
Aims of Clinical Neuropsychology

• Determine Pathology / Lesion localisation
• E.g. are memory deficits in an elderly patient
  due to depression / stroke?
• Clinical Neuropsychologists can build up picture
  of brain damage sites by testing patient with
  tests known to be sensitive to damage in specific
  brain areas
• Increasingly redundant now due to the advent of
  neuroimaging techniques
• But in some cases sophisticated testing can
  indicate damage when imaging techniques show no
  gross damage (e.g. hypoxia, heavy metals,
  psychiatric disorders)

3
Aims of Clinical Neuropsychology

• 2. Characterise cognitive deficit
• Clinical neuropsychologists can build an accurate
  picture of patients cognitive strengths /
  weaknesses
• E.g. How severe are memory impairments? Will they
  impact on everyday life?
• Has important implications for the development of
  rehabilitative programs.
• E.g. is info retained if presented visually
  rather than verbally?

4
Aims of Clinical Neuropsychology

• Determine a baseline performance
• Clinical neuropsychologists often perform
  comprehensive batteries before and during various
  neurosurgical procedures
• E.g Excisions for epilepsy, psychosurgery,
  implanting neural stimulators
• Post-surgery testing allows an assessment as to
  whether functions have improved or deteriorated.

5
Functional Neuroanatomy
Brain can be divided into four lobes Frontal,
Parietal, Occipital, Temporal
6
Functional Neuroanatomy Orientation

• 3D Structure so described in 3 Dimensions
• There are lots of different terms used
• They make more sense for rats

• Some Latin
• Rostrum Beak
• Caudalis Tail
• Dorsum Back
• Ventrum Belly
• Latus Side
• Medius Middle

• Other dimension
• Lateral / Medial

• Combinations are common - eg. Dorsolateral /
  Ventromedial

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Functional Neuroanatomy Orientation

• 3 Dimensions describe 3 perpendicular planes

• Horizontal (aka Axial or Transverse)
• e.g. MRI / PET Images
• Midsagital or parasagittal

8
Neuroanatomy - Frontal Lobes
Can be divided into

• Motor Control of movement
• - weakness / paralysis
• Premotor Integration of motor skills / learned
  action
• - uncoordinated movements / impaired motor
  skills / speech
• Prefrontal Complex cognitive functions
• - difficulties with planning / decision making /
  inhibition / memory / attention / perseveration /
  personality changes / aphasia etc etc.

9
Neuroanatomy - Parietal Lobes

• Functions
• Sensory integration, visual attention,
• Lesions can cause
• Neglect, extinction, dyscalculia, anomia,
  agraphia, alexia

10
Neuroanatomy - Temporal Lobes

• Functions
• Memory, auditory processing, object
  categorisation
• Lesions can cause
• Amnesia, Wernickes aphasia, prosopagnosia,
  category specific deficits.

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Neuroanatomy - Occipital Lobes

• Functions
• Sensory integration, visuoperception, vision
• Lesions can cause
• Heminopia, Blindsight, Visual Agnosia, Colour
  Agnosia

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Common Causes of Neuropsychological Deficits

• Head Injury
• Penetrating
• Closed
• Vascular Disorders
• Ischemic
• Heamorrhagic
• MID
• Neurodegenerative disorders
• Cortical dementias
• Subcortical dementias
• Misc

13
Head Injury

• Most common cause of brain damage
• Modern AE practise ensures an increasing supply
  of patients
• 500 people a day sustain a head injury leading
  to brain damage
• Patients predominantly healthy young men
• Average life expectancy after injury 52 years.
• Severity of head trauma relates to behavioural
  and neuropsychological outcome
• Only 15 of people sustaining severe head
  injuries ever return to work.

14
Penetrating Head Injury

• WW I II provided material for the first large
  neuropsychological group studies
• Although damage may appear local, spreading
  shockwaves may damage other areas
• Swelling / bleeding may also effect other areas
• Generally less severe than closed head injuries
• Despite some discrete cognitive dysfunction, most
  people can return to work
• But often produce seizures (epilepsy)

15
Closed Head Injury

• Damage typically occurs in two stages
• Primary Injury - impact
• Secondary Injury - consequent physiological
  processes
• Primary Injury
• Coup / contrecoup
• Deceleration contusions
• Shearing - axons blood vessels
• Secondary Injury
• Heamorrhages
• Ischemia
• Edema

16
Closed Head Injury

• Damage can be local or diffuse, most commonly a
  combination
• Reduction in cognitive efficiency
• Severity (based on LOC and PTA)
• Mild 0-20m LOC, 0-60m PTA attentional deficits,
  verbal retrieval problems, emotional distress
• Moderate 1-6h LOC, 1-24h PTA wide variety of
  defecits - memory problems common, difficulties
  with ADL.
• Severe gt 6h LOC gt1d PTA comprehensive
  cognitive and emotional dysfunction. Untestable
  for weeks / months

17
Vascular Disorders

• Stroke (CVA) a focal neurological disorder of
  abrupt development due to a pathological process
  in blood vessels
• Nervous tissues cannot survive more than a few
  minutes without glucose and oxygen
• 66 of strokes are non-fatal.
• Ischemic or Heamorrhagic (but distinction is not
  clear cut)
• Tend to be lateralised
• Silent or lacunar strokes - small lesions in
  deep brain structures

18
Vascular Disorders

• Ischemic (obstructive) strokes
• Thrombosis buildup of fatty deposits block blood
  vessels
• Embolism - fatty deposit from elsewhere carried
  to the brain
• TIAs - emboli pass on before too much damage is
  caused
• Heamorrhagic strokes
• Hypertension - tend to be subcortical
• Aneurysms - e.g. AACoA
• AVMs
• Multi-Infarct Dementia (MID)
• Repeated small infarctions
• Often misdiagnosed as DAT

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Degenerative Disorders

• Cortical Dementias
• Alzheimers Disease (DAT). Memory most effected
  in early stages
• Frontotemporal Dementia (fvFTD, tvFTD) -
  dysexecutive problems, semantic dementia
• Subcortical Dementias
• Parkinsons Disease Some frontal signs
• Huntingtons Disease frontal signs, visual memory
  deficits, depression
• PSP, SRO
• Multiple Sclerosis

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Degenerative Disorders

• Toxic conditions
• Alcoholism
• Korsakoffs Syndrome
• Recreational Drugs
• Environmental / Industrial Toxins
• Solvents
• Pesticides
• Metals
• Infectious Processes
• Neurosyphilis
• HIV AIDS Dementia Complex
• Herpes Simplex temporal / limbic structures most
  affected
• Tumours
• Hypoxia