Kessels, R., Eling, P., Ponds, R., Spikman, J., & Van Zandvoort, M. (2017). Clinical Neuropsychology.
Boom publishers Amsterdam
CHAPTER 1 CLINICAL NEUROPSYCHOLOGY: A HISTORICAL OUTLINE
A clinical neuropsychologist (CNP) specialises in the assessment and treatment of problems related
to brain diseases or disorders. Neuropsychology as a scientific field was shaped as such in the
twentieth century in the USA.
- Hippocrates (400 B.C.) taught that all abnormal behaviours and emotions stemmed from
the workings of the brain.
- Galen (129-217 AD) Romans and Greeks: the body contained four elements (water,
earth, air, fire) and four humours (blood, phlegm, yellow bile, and black bile).
- René Descartes (1596-1650): the soul is an undivided, independent yet immaterial entity.
Soul was supposed to be located in the pineal gland or epiphysis.
- Gall (1758 – 1828): there are mental organs located in the grey matter or cortex of the
brain Phrenology
o Tested by clinico-anatomical method (studying cognitive loss of function after the
death of a patient, linking the location of the lesions to the type of functional
impairment.
1.2 Cell theory
An important question in the brain-behaviour debate is that of localisation. The Greek phenomenon
psychikon hegemonikon is the guiding principle. The Greeks distinguished between three different
forms of souls (survival, activities of organism in relation to environment, higher-order soul). Humans
had all three.
- The ventricles were considered the site of the mind. The mind was divided into different
functions:
o Sensus communis (combined senses; supposed to receive information from
senses)
o A cell that interpreted an image, gave it meaning
o Third cell that stored information; memoria
Today this cell theory is the basis of our ideas about cognitive psychology. The mind can process all
information and there are no separate functions. The ideas about individual differences is
characterised by personality or character. Physiognomy is the interpretation of the face.
1.3 Descartes
The body (the res extensa) and the mind (the res cogitans). The res cogitans is not material, however,
Descartes believed it was located in the pineal gland. He saw the mind as a kind of manager.
1.4 Gall and the localisation issue
Phrenology, assumed that all psychological functions were innate. Each of these functions had
independent organs (breaking with the traditional view of general information processing mind that
is capable of processing all kinds of information. Gall proposed that these functions were located in
the cortex.
- Gall’s most important proposition was that these were independent functions
, - If one function is better, it is better organised and of a larger size
- Functions were locatable by lumps on the skull
- Flourens: Countered these ideas with his research, suggesting it was not the location of a
lesion but rather the degree of damage that determined which functions were affected.
1.5 The clinic-anatomical method
Bouillaud argued that Gall’s fundamental starting point (localisation of function) was correct.
Research was done by charting the specific loss of function in patients with focal encephalopathy
(clinic-anatomatical method).
- Broca (1861) presented Patient Tan (only capable of saying tan). The patient had a lesion
in his brain located in the area now called Broca’s area.
o Specific mechanism that is concerned with a sequence of sounds that can form a
word.
o Lesions is always on the left side of the brain let to the thought of an
asymmetry in the localisation of language, and whether individuals are right-
handed or left-handed.
Jean-Martin Charcot and his students described many new medical conditions, such as MS,
amyotrophic lateral sclerosis (ALS) and Tourette’s syndrome, he described a more detailed
description of Parkinson’s disease.
After Broca, the idea emerged that language could have different functions, not only for language
production, but also for language recognition. Carl Wernicke claimed that there was a separate
centre for the recognition of word pictures.
- Centre was located in the temporal lobe (terminus of the auditory pathway).
- A disorder could be caused by a lesion in a connecting pathway or in the centre.
- Wernicke regarded the brain as an instrument in which sensory stimuli were linked to
motor reactions
John Locke (1970) was a strong advocate for empiricism, he did not believe in innate characteristics
and knowledge. Everything was learned, and learning was accomplished through associationism.
Today, some people tend to believe in a description of cognitive functions that involve modules,
while others are more inclined to a belief in neural networks that are formed by the influence of
experiences.
1.6 Holism
Many argued the view of different locations, arguing that areas of the brain generally worked
together. The Gestalt movement, the view that the whole is greater than the parts. Kurt Goldstein
contended that sound functioning of the brain was of paramount importance in order to be able to
reflect on incoming stimuli instead of simply reacting directly to them. He called this abstract
attitude.
1.7 Luria: a global model
Aleksandr Luria sought a balance between holistic and localizationist views. The brain was supposed
to be a single complex functional system within which various subsystems contribute to joint activity.
These systems arise as a result of interactions between the developing child and its environment, and
they change during the child’s development as a result of learning processes.
, - The functional systems of the whole brain is flexible and adaptive localisation through
lesions is not possible.
- Luria was convinced that accurate scientific analysis of behavioural disorder would
always demonstrate a specific disruptive factor.
- Every brain area is linked to one or more specific factors.
Luria summarised the functional architecture of the brain using three broad classifications:
- 3 continually interacting functional units, related to the subcortical, posterior, and
anterior brain areas
- 3 hierarchically organised levels of processing, related to primary, secondary, and tertiary
zones in the brain
- Behaviour that is or is not regulated by language processes, related to the left and right
hemisphere, respectively.
All functional units listed above involve mental activity. The first unit is used to regulate alertness and
attention (diencephalon, medial areas of the cerebrum). The second is cognitive functional unit is
cognitive information processing (central fissure, posterior areas of lateral cortex). The third unit is
used to organise behaviour (front of central fissure, motor, premotor, and prefrontal cortex).
Within each of these units a distinction can be drawn between primary, secondary, and tertiary
zones.
- The primary zones are projection areas of sense and locomotion. Accurate topological
representation.
- The secondary zones largely modality specific. They are involved in the further processing
of and assignation of meaning to the incoming information. In the third unit they are
implicated in the preparation for locomotion.
- The tertiary zones are necessary for multimodal and cognitive integration and the
forming of intentions and plans and the evaluation of one’s own behaviour.
Luria placed emphasis on internal-speech for the regulation of cognitive functions, and for him the
left hemisphere was therefore the dominant half of the brain.
1.8 An initial impulse: the test battery
Using tests, psychologists can study and describe cognitive functioning systematically.
1.9 Neuropsychology as an independent discipline
Two major developments occurred in the USA in 1960 that resulted in the emergence of
neuropsychology.
- Norman Geschwind wrote articles about disconnections. He also set up a clinic for the
study of aphasia.
- Roger Sperry carried out research into the effects of split-brain surgery. The intervention
was designed for patients with epilepsy, and was successful. The negative effects of
cutting through the corpus callosum were limited.
o The right side of the brain was better at performing certain functions that the left
side hemisphere specialisation
o Variety of research methods became available that could be used to conduct
research into localisation of function in individuals who had not suffered any
brain injury.
, 1.10 Cognitive neuropsychology
1.10 Modules
Jerry Fodor believes, just as Chomsky, that language ability is an innate specific property, with syntax
being of paramount importance. We have no awareness of these language processes and we have no
control over them. Representation: the information that can be processed by a module or produced
as an output. Process: the calculation, computations, or transformations that are carried out on the
representations. A module:
- Can only process certain information (if domain specific)
- Is innate
- Carries out its work regardless of what other processes are occurring (cannot be
influenced by other processes)
- Is computationally autonomous and has its own neural architecture, a module does not
share any attention capacity, memory processes, or other processes with other modules.
Cognitive neuropsychology systematically analyses the effects of brain damage on cognitive
functions, mostly by looking at the nature of errors. With this analysis a theoretical view is tested
(collection of boxes; sub-processes). These sub-processes are then examined to determine whether
they can correctly predict certain patterns of correct and incorrect responses.
Marr (1982) formulated starting points for the construction of a theory about specific cognitive
functions. Marr proposed that the description of these representation levels and the transformation
rules were in fact also independent of the specific hardware used to achieve function. Artificial
Intelligence was born.
On the basis of Fodor’s and Marr’s ideas many researchers started to propose models for all kinds of
functions. Different forms of dyslexia, agnosia, etc.
Marr’s approach, a blueprint for modular models of cognitive functions, is based on serial processing
– the conversion of information to a subsequent level of representation.
1.10.2 Neural networks
Computer software that simulates a certain cognitive function. They were developed as systems that
would work in the same way as the brain, with each system consisting of a large collection of nodes
(cells) that are connected together (by dendrites). A neural network learns by trial and error.
- Emergent property: learning by practice
- Gracefull degradation: if the model is taught certain functioning that damages certain
nodes, the whole function does not fail, but takes part of the information that is not
taken into consideration.
- Content addressability: in neural networks a small amount of the information can
activate the whole memory trace.
A major problem for the networks is that they offer little insight into how the process actually works,
and what characteristics of stimuli are recorded and are available for possible reactions of a test
subject.
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