Movement Disorders

Movement disorders

Cerebral palsy is another movement disorder. That effect movement and posture. It cannot be categorised as one single syndrome, disorder or conditions as this motor deficit can take many form. It is usually caused by brain damage. Lesions to the corticospinal tracts, basal ganglia, brain stem and cerebellum are responsible for this disorder but there are difficulties labelling the lesions with clinical finding. Brain abnormities may develop during fetal development or periods up to 3 years after birth. There are three main types cerebral palsy which are:

•       Spastic cerebral palsy
•       Dyskinesia cerebral palsy
•       Ataxic cerebral palsy  

movement disorder is the inability to produce and control movements. Simple movement require a complex system of control and impairment to the prefrontal and premotor cortex can cause movement that are too week, too forceful too uncoordinated, or too poorly controlled for the hands and in addition unwanted movement can occur unexpectedly. Examples of this disorder are:

•          Parkinson disease
•          Huntington disease
•          Tourette syndrome
•          Restless leg syndrome

 Movement is produced and coordinated by several interacting brain structures this includes the motor cortex, the cerebellum and the basal ganglia which are group structure that are deep within the brain.

 The cerebellum and the motor cortex send information to the basal ganglia to control involuntary movements whereas the basal ganglia send out information to the motor cortex to help initiate, regulate pattered movements.

Kolb, B., & Whishaw, I. Q. (2003). Fundamentals of Human Neuropsychology (5th ed.). New York: Worth Publishers.

Neglect - blindsight

Neglect in dyslexia

Not only is neglect a spatial disorder it can be found in words

-the case of NT

- AGE 9 – diagnosed of having language problems (Friedman and Nachman – Katz 2004)

- Did not have any visual brain damage or abnormities –but had left word base neglect dyslexia 

-  He was unable to read the left side of words – this was demonstrated through his drawing

-His native language is Hebrew – so he wrote from left to right- so when he write he  leave out or substitute the final words of single letters on the left hand side  – finding show 96%   of his words show these irregularities

- When giving pair of words or sentences – he neglect the left part of the word but not the whole word on the left hand side of the paper

- Improvement are made – by making the neglect word part different colour or making it flash (in other world making it stand out)- also by presented the word vertically than horizontally

-finally does not sown neglect for numbers or symbols

Neglect

Spatial neglect – is the inability to respond, report or attend to the stimuli or event that is in the opposite side of the brain injury

The effect of neglect can happen after months and years of the lesion.

Damaged to the right hemisphere  can lead to neglect of stimuli  on the left hand side and damage to the left hemisphere can lead to neglect of the stimuli on the right however this is not as serve as right damage .

Short term memory * spatial working memory

Short term memory can also appear with neglect symptoms when there is damage to the right parietal lobes  

A study was conducted to test the different in impairment with those that have right neglect and non parietal damage with those with parietal damages using a imagery test that consist of a map of familiar piazzas

Results show that those that had right neglect with parietal damager were significantly more impaired than those that had no injury to the parietal lobe    

Not being able to hold spatial information in the working memory can lead to patients being unable to remember the locations of stimuli- Malhotra et al 2004

Case study

Patient BI

Symptoms of left neglect and right temporal haemorrhage- lead to impairment of spatial location - when giving a visual search task e.g. – mark as many T that u see on the page that are among mix letters  -results show that repeatedly search on the right side-  returned to item that were already noted and saw them as new items

Results show that subtle memory deficit (damage) may affect the performances   with performances of neglect patient 

In regard to the different type of neglect they can be defined by their underling mechanising:

-inattention underlies sensory and perceptual neglect

- Disorder if action and intention underling motor neglect

-representation underlies the neglect of the visual and metal images

Examples of neglect

Difficulties in reading the time

Missing food on one side of the place

Dressing up on one side of the body

 Patient are normal unaware of this behaviour – (anasagnosia) until it pointed out to them

 How to test for spatial neglect

Test

Line bisection – patient are giving lines that are vertical or horizontal and are instructed to put a mark in the middle of the line those that have neglect mark the line closer to the right side when the line is horizontal and the upper end of the line when it is vertical –

Reducing spatial neglect

Recovery can be slow – from 18^th to indefinably

Flashing a red light to the left side of a patient when they are reading copying or cancelling reduces neglect – this works because patient pay attention to one side of an imagery task

Making salient on the right hand side less important to can also reduce neglect  

Vibrating the left posterior neck muscles - this stimulate the neck muscles to generate a body centred frame, the vibration corrects the displaced body- centred frame

Caloric vestibular stimulation – it elicit a vestibular ocular reflex – this can reduce eye movement in the opposite direction to the Attention bias

Opokinetic stimulations – improves voluntary eye gaze direction  

Result 

17 of out of 18 improved when giving spatial neglect test – improvement were short term

These strategies seem to be used rectify inability to automatically to shift attention to the neglect side

 Location of lesions is the spatial neglect 

Lesions are found in the right parieto –temporal cortex

Injury   the inferior and temporal cortex

Damage to the basal ganglia and thalamus following a subcortical stroke – all linke to sensory neglect 

Conception to explain neglect

Pragmatic map - Damage to the perceptuomotor cortical and subcortical can lead to neglect  when they are stimulated this activate spatial awareness – each map have different mechanism and responsibilities for head arm and leg movement

the eye

Why do we need to move ours across a scene?

The information that is recorded in the retinal region only contains 50% of what is sent to the brain through the optic nerve.

When we move our eyes to focus on a specific region of an image or object, we are essentially placing the foveal region of the eye on top of the area which is currently within main focus of the lens in our eye. letting the foveal region register the image, the brain get the highest resolution possible for the image of the interesting area to process

·         The human visual field spans about 220 degree

·         divided in 3 main regions: foveal, parafoveal, and peripheral region

·         register visual data through the foveal region which constitutes less than 8% of the visual field

Would it not be easier if we could see the whole scene in front of us at once?

In order for us to accumulate all the information of a scene at one our skull need to be bigger as a normal size skull is unable to deal with all the information. In addition the high spatial resolution is located in a small section of the retina.

For this to be possible we would need to have slightly bigger eyes and brain to register the information that is sent. You would also need more reception and structures to process that information this would then increase the amount of neurons and photo receptor. Therefore this would increase the need to feed those neurons and photo receptor therefore incensement in energy consumption. Also you Need the photo receptor spread all across the retina not just in the fovea  you would need high density mean that you can get everything from the scene but you going to get lot of information that you do not need.

The brain consume a lot of energy glucose hungry structure – when looking an anorexic  person the brain and the cognitive activities  are normally ok  but the mussels fade away because  a lot so the energy that is need for  the brain is protected through evolutions . The energy that the brain is consuming is not going to be available muscles start to decrease. – When looking at extreme anorexia there are mechanism that are emplaces to  protect the brain as it steel the energy from other part of the body.

When the brain does not have the bare minimum that it need it put the body in a comma so it perceives it by not being active. You would not see an extremely hungry person that would be anxiety to find food but when the energy supply is so low they would enter a stage where they are unable to move and are waiting to die – this is seen with cases of extreme farming –no energy to move hence the reason why they do not get up and search for food.

Animals effect – we seen that some animal have smaller brain and bigger bodies this is because  the motor control that they have is smaller and the energy  that is consumed there the brain need less energy. Save energy by not having highly developed contrive skills

What does FEF mean? And what is its role in vision?

FEF it the abbreviation for frontal eye field it is located in the frontal cortex and controls generation for motor commands for pointing the eye and directing   the eye to desire location and play a role in directing spatial attention.

Topic of the week

Agnosia is a recognition disorder. Visual information is only useful when objects can be recognised by the brain. Brain damage can lead to several problems with the visual perception Visual Agnosia inability to recognize objects even though elementary visual functions remain unimpaired.

Can be broken down in to two subsections

·         Apperceptive Agnosia

Impairment occur during the perceptual processing

The case of HJA- he suffered from bilateral stroke was unable to recognise picture but give a reasonable description of it parts.

e.g.  a carrot – bottom bit seem solider the other bit seem feathery

Diagnosis is that his has difficulties in perceptual grouping mechanisms  

·         associative Agnosia

Impairment occurs during visual memory representation. (lissaure 180)

Object constancy – object remain the same even in different positions and lighting condition   

Studies have shown that they are able to name and recognise objects from a usual view rather than an unusual- (Humphreys& riddoch 1984)- this happen when there is damage to the right parietal lobes

The parietal lobes – may have mechanisms to extract the structure of an object and for rotating objects so that it can be identified at different view points

  

   Object Agnosia

Unable to decide the correct orientation of an object or whether the two objects presented have the same orientation even thought they can recognise the object.  

FMRI studies show that using pair of object that are different size and view point can test object constancy. For the reason that when the same object are pair repeatedly the response of the neuron decreases over time. Therefore you can correlate the different factors such as size and view point with the responses of the FMRI results.

Finding suggest that left infero – temporal region response irrespective of view point for size whereas view point was important for the comparable region in the right hemisphere

Prosopagnosia

The inability to recognise previous familiar faces.  

Face recognition – Bruce and Young (1986) the is a different between the process used to recognise familiar and unfamiliar faces.

Familiar faces are recognised by matching it to a stored face data base description

De Renzi (1986) – was unable to recognise some of his family members but was able to identify them through their voices and other non facial information

The fusiform face area in the right hemisphere may specialize in faces Kanwisher(2000)

Category perspective – a area of the brain that can recognise different categories of objects such as animal, face, body and words.

Further studies has identified that there are other part of the brain that is related to visual recognitions which is:

Parahippocampal- place are this is reasonable for scene that are more than objects and extrastriate body are – responds to the human body more than faces and objects.   

The New philosophy

This article gives descriptive explanation between the correlation of mental illness and neurology. The author attempts explain these solutions using evidence from conflicting approaches which are the chemical imbalances and Freudian approach. Which coincides with the nurture nature debate? This article focuses on brain impairments that result in symptoms of mental illness. This theorisation is called Evolutionary Nero-psychiatry

The author distinguished the difference between a normal person who has free will to innovate movement of his motor muscles in relations to a person who has hysteria who is unable to wilfully move his leg or arm. A PET scan will show that both patients have the intention to move the arm or leg because the brain would show activation in the pre-motor cortex and ventromedial frontal lobes. However when analysing the anterior Cingular, results show that there is no activation with patient diagnosed with hysteria therefore suggesting that signal are being block in this area inhabiting the arm or leg from moving. Pervious research would suggest that this was due to psychological trauma, effecting that arm or leg as they were unable to detect any lesions in the brain. Now there are empirical evidences to suggest that the anterior Cingular is closely related to the limbic emotional centre giving plausible reasons why they may be an emotional connection.   

The writer also draws on other related theories such as Darwin perspective on evolution where the writer identifies that mental processes tend to coincide with physical movement rather than brain processes this enabled the conscious to feel that a command evokes the movement at the same time. Whereas the brain kicks in about a second prior to the commanded action. This therefore suggests that there is a innervated neural delay. This makes it easier for humans to understand and react to the world. Unlike those who suffer with Catard syndrome.

The structure of the articles is clear and understandable as it uses definitions, causes, theoretical explanations and examples to explain the disorder. Such as Capgras delusion this is when a normal person believes that his mother is an impostor this may be caused by an accident which led to head injuries. The theoretical argument is that the visual area is able to recognise the face however it is unable to show emotional significance therefore the patient reject the idea that there is mother as they are unable to produce a galvanic skin response which is a response that you get when you're shown s stimuli with emotional importance through sweating.

Catard’s syndrome is when all the senses are disconnected from the emotional centre in the brain; patients with this disorder may claim that they are dead. As they are unable to respond to the world and have any emotional ties. This relates to the authors theory that mind and matter are intertwined with each other and that they are two ways of experiencing the world as each of them complete itself.as a result if once missing may explain why some people experience derealisation and depersonalisation. This is when the world feels like a dream or person feels unreal. The mental process in the brain shows that the   anterior Cingular and parts of the frontal lobes in the brain become extremely active this then causes a temporary shutdown to the amygdala and the limbic emotional centre which suppress potential emotions, such as fear and anxiety. This also occurs with epileptic patients because during their seizure they are in dreamy state.

Schizophrenia are unable to identify the differences between images and ideas that are generated by thought and actual stimuli that are in the environment. The author demonstrates this through a written experiment where he tells the reader to use their left index finger to tap repeatedly on the right index finger to express how schizophrenic interpret information. Finding of experiments claims that the mechanism used to send the information to the motor centre is flawed resulting in patients claiming that someone else is controlling the actions.

The History of Neuropsychology

The article gives a brief description using empirical evidence to explain in chorological order, how neuropsychology developed from its earliest form into   how it is used in modern day. The author uses subheadings to break down keywords and definition, such as identifying psychology as a discipline. this is the study of human behaviour and explaining how it influences neuropsychology where it is state that it is a study that identifies the relationship between brain function and human behaviour. It also uses pictures to demonstrate detailed descriptions for example Trephanation was demonstrated by pictures of skull fractures, one showing the effect of survival , another the effect of death and last of all picture showing multiple Trephanation. Trephanation was a method of scraping, chiselling or cutting bone from skull it was a surgical procedure to get rid of evil spirit. An examination was conducted by Verona and Williams (1992) on the techniques, location, size, healing, and pressure of the fracture. Finding show that most of the surgeries was performed at the frontal and upper parietal region. This therefore suggests that they may have associated the “evil spirit” with a specific area in the brain. In additions the Stacking and circular grooving procedure had a higher success rate in contrast to straight cutting and drilling. The Ancient Greeks had broken away from this concept into another perspective, identifying the heart as a mental function this was theorised by Aristotle’s, he believed that the heart was the organ of the human mind this was called the Cardiocentric hypothesis. He argued that it was the root of intelligence, motion and sensation. Using ideas from dualism he developed the notions that it was through the heart that the physical body and the mind interacted. This conception was then modified by Pythagoras where he stated that the process of thought was located in the brain rather that the heart, however he also portrayed that he had four prior lives and remembers them vividly. Although the author credit Pythagoras him stating this additional fact shows that he believes that Pythagoras is a bit eccentric. Furthermore he shows approval of Hippocrates accomplishments suggesting that he is an “outstanding figure” and is known as the “father of medicine” and the founder of “Hippocratic School of medicine”. Hippocrates distinguish that paralysis occurs on the opposite side of the body in relation to the head injury. The author identifies key figures the in chronological order provides brief details on their contribution to neuropsychology and how their ideas led to further development through other key figures such as nemesium and saint Augustine it were influenced by studies from Galen and his version of psychic and humours. It was not until Vesalius that that imperial evidences triumph over supernatural ides. Using detail observation of brain anatomy to study the cell doctrine, the authors also show how theory build upon theories this can be seen through the development of localisations starting with phrenology – gall perspective that the brain was composed of different organ each responsible for different basic psychological traits based on categories such as cautiontiousness, combativeness, agreeableness even though he was wrong. Broca also did investigation on localization and found that expression of language is located at the left frontal lobe this was then furthered by Wernicke that complex mental function for example language- is a combined process of a number of subcomponents process represented in different area of the brain. This also influences other area in psychology such as Freud when we’re had his own theories which were different to the Broca and Wernicke.