Introduction to Neuropsychology

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Introduction to Neuropsychology For Psychiatry
Residents
Vaughan Bell
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Course Outline

• Introduction to neuropsychology
• Introduction to neuropsychological evaluation
• Referrals, reports and interpretation
• Evaluation of psychiatric patients

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What is Neuropsychology

• Neuropsychology is the science of how the
  structure and function of the brain relates to
  psychological processes.
• As a basic science it tries to understand these
  links experimentally.
• As a clinical science it aims to understand how
  specific impairments relate to impaired brain
  mechanisms, or vice versa.
• In neuropsychology, these two aims are strongly
  linked.

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Phineas Gage

• A railroad worker in Vermont, known for his good
  character and responsible attitude.
• Suffered an injury in 1848 where a tamping iron
  was shot through his head when setting gunpowder
  to break rocks.
• He did not lose consciousness and he walked home.
• He was later seen by Dr Harlow who wrote up his
  case.

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Skull and Life Mask
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Damasio et al (1994) Reconstruction
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Effect on Gage
Dr Harlow reported He is fitful, irreverent,
indulging at times in the grossest profanity
capricious and vacillating, devising many plans
of future operation, which are no sooner arranged
than they are abandoned.
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Link to Function

• This was some of the first evidence that damage
  to specific areas of the brain could affect
  personality and behaviour.

• Later Paul Brocas autopsy on a patient with
  expressive aphasia found a specific lesion in the
  left frontal lobe, now known as Brocas area.

• This suggested language was not single function
  and could be linked to certain brain circuits.

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Trench Warfare and Scotoma
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Holmes (1916) Scotoma Lesion Map
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Modern Neuropsychology

• Contemporary neuropsychology uses a variety of
  techniques to understand mind brain links.
• Neuroimaging
• Computational modelling
• Experiments on healthy participants
• Lesions studies
• Studies on psychiatric disorders

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Lesion Studies

• Understanding how brain damage affects human
  abilities is still the most powerful tool in
  neuropsychology.
• One of the key techniques in both research and
  clinical work is the dissociation - a difference,
  break or uneven performance on tasks.
• A dissociation between patients suggests that the
  task is not controlled by a single cognitive
  process.
• A dissociation within a patient suggests
  difficulties in specific abilities.

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Video Segment
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Dissociations

• In this example each patient had a single
  dissociation between one ability object
  perception and another face perception.
• Considering both patients, there is a double
  dissociation so we know they rely on different
  brain processes.

Objects Faces
Patient 1 ? ?
Patient 2 ? ?
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Dissociations

• The double dissociation is a scientific tool that
  helps us understand mind and brain function.
• In a clinical patient, we can link deficits to
  what we know about neuropsychology
• to understand what has gone wrong.

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A Rough and Incomplete Guide to the Brain
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Early Visual Perception Deficits

• Damage to the early visual system will produce
  things such as
• Visual field deficits
• Orienting difficulties
• Impairments in shape, form or size
  discrimination.
• Colour blindness
• Motion blindness

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Efrons (1968) Shape Task
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Dorsal Stream
The where or how stream
Ventral Stream
The what stream
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Associative Agnosia
Associative Patient HJA (Riddoch and Humphreys,
1987) Copying without Naming
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Apperceptive Agnosia
Original
Patient Copy
Apperceptive Patient HC (Sparr et al., 1991)
Impaired Copying of Simple Shapes
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High Level Vis Perception Deficits

• Prosopagnosia selective impairment in
  perceiving faces.
• Simultanagnosia difficulty perceiving more than
  one object.
• Dorsal type can identify an object but cant
  locate them in space.
• Ventral type can perceive more than one object,
  but can only identify one at a time.

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Some Memory Systems

• Working memory less than 30s, manipulated by
  executive system.
• Long-term memory
• Semantic memory facts
• Episodic memory events
• Alternative long-term memory classification
• Declarative memory consciously describable
  information
• Implicit unconscious skill learning,
  conditioning etc

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Memory Functions

• Encoding perception, selection and transfer of
  information into memory.
• Storage maintenance of information in a
  retrievable state.
• Retrieval reactivating stored information for
  conscious retrieval or unconscious use during
  task performance.

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Key Memory Circuits
Hippocampi
HM (1926 2008)
Including a circuit with the fornix, mamillary
bodies and septal nuclei.
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Key Memory Circuits
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Working Memory Problems

• Can be caused by damage to visual or auditory
  storage.
• But more usually due to executive system damage
  which affects how well we use these stores.
• Double dissociation between storage and
  manipulation of information I working memory
  (Mintzer and Griffiths, 2007)
• Lorazepam manipulation impairment
• Scopolamine storage impairment

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Long-term Memory Problems

• Amnesia for episodic memories
• Antereograde inability to encode new
  information
• Retrograde loss of pre-injury information, most
  recent memories most likely to be affected.
• Semantic memory impairments
• Semantic dementia loss of words and meaning.
• Selective impairments e.g. living vs non-living
  things.

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Video Segment
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Long-term Memory Problems

• Transient amnesias
• Post-traumatic amnesia correlates with extent
  of injury
• Transient global amnesia sudden, dense amnesia
  that resolves within hours.
• Transient epileptic amnesia similar, shorter
  duration and associated with clear seizure
  activity.
• Psychogenic amnesia syndrome of hysteria,
  often pure retrograde amnesia, and can include
  loss of identity and wandering (fugue state).

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What is the Executive System?

• Mainly concerned with the co-ordination of other
  cognitive resources.
• e.g. the use of attention, organisation of
  actions, inhibition of responses, monitoring
  (metacognition).
• It is a dynamic, online system, that may only
  fully engage some aspects in real world
  situations.
• e.g. Saver and Damasios (1991) patient EVR
  displayed severe day-to-day executive problems
  but passed standard tests of executive function.

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What is the Executive System?

• So it is particularly involved in handling new,
  novel or potentially risky situations.
• Norman and Shallice (1980) outline five types of
  situation where routine activation would not be
  sufficient.

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Norman and Shallice (1980)

• Those that involve planning or decision making.
• Those that involve error correction or
  troubleshooting.
• Situations where responses are not well-learned
  or contain novel action sequences.
• Dangerous or difficult situations.
• Situations which require the overcoming of strong
  habitual response or resisting temptation.

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Neuroanatomy

• Most associated with the prefrontal cortex
  although there is increasing evidence that
  parietal interactions are important (Collette et
  al., 2006)

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Dysexecutive Syndrome

• Damage can result in
• Problems with memory (e.g. working or episodic
  memory)
• Problems with affect and social judgment
  (inappropriateness, emotional lability /
  blunting, social perception, theory of mind)
• Problems with abstract thinking and intentions
  (planning, understanding rules, cognitive
  flexibility, inhibition)

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Video Segment
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Attention

• Typically divided into three main types (Posner
  and Petersen, 1990)
• Spatial attention distinguish and detect
  sources of information in space
• Selective or focused attention focus in / block
  out certain sources.
• Arousal / sustained attention maintain focus

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Neglect

• Hemi-spatial neglect is one such disorder which
  particularly occurs after right parietal damage.

Severe neglect
Mild neglect
From Vallar (1993)
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Copied Drawings
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Copied Drawings
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Copied Drawings
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Line Bisection

• When asked to mark the centre point of a line,
  patients mark to the right.

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Video Segment
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Language

• Language involves
• Production (e.g. speaking, writing, syntax,
  articulation)
• Comprehension (e.g. reading, listening, syntax)
• Knowledge (e.g. names, words)

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Wernickes area
Brocas area
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Arcuate fascilulus
From Rodrido et al. (2007)
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Speech Problems

• A few of the many aphasias
• Brocas aphasia (normal comprehension, non-fluent
  speech).
• Wernickes aphasia (impaired comprehension,
  fluent but meaningless)
• Conduction aphasia (normal comprehension, fluent
  speech, wrong words and poor repetition)
• and many others.

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Reading / Writing Problems

• Dyslexias and agraphias are broken down into two
  main types
• Peripheral dyslexia problems with word or
  letter perception.
• Central dyslexia problems with the semantics or
  syntax of language
• Peripheral agraphia problems with motor
  control.
• Central agraphia - problems with the semantics or
  syntax of language
• and various combinations.