The Linguistic Impairment and Its Relation to the Brain: a Nero-linguistic Study on Some Aphasic People in Yemen Dr. Hasan. M. S. Jaashan Assistant Professor(Linguistics) English Department Al-Mahweet College of Education Sanaa University Yemen Republic
[email protected]
ABSTRACT Aphasia is a disorder that results from damage to portions of the brain that are responsible for language functions. For most people, these areas are on the left side (hemisphere) of the brain. Aphasia usually occurs suddenly as a result of a stroke or head injury, but it may also develop slowly, as in the case of a brain tumor, an infection, or dementia. The disorder impairs the expression and understanding of language as well as reading and writing. Aphasia may co-occur with speech disorders such as dysarthria or apraxia of speech which also results from brain damage. Anyone can acquire aphasia, including children, but most people who have aphasia are middle-aged or older. Men and women are equally affected. According to the National Aphasia Association (NAA), approximately 80,000 individuals acquire aphasia each year from strokes. About one million people in the United States of America currently have aphasia. This research aims to conduct a neurolinguistic study on some retarded people who are put under speech therapy in the National Center for Speech Teaching in Sana'a, Yemen. The informants of this research are 75 patients who have different language disorders. They are selected randomly out of 120 patients. The aims of this study: This study aims to; 1- Collect the information about every patient under study to know the linguistic symptoms of aphasic cases. These symptoms include the difficulties of language comprehension and language production. 2- Locate each language disorder in its specific area in the brain. This will be done with the help of neurologist and neurosurgeon. I will show them set of tomographic pictures of the brain of a Broca and Wernicke's patients. They will tell us the exact damaged points in the brain that cause language disorder. 3- Show some physical techniques and methods the speech therapists use to rehabilitate the language of aphasic people in the Speech Therapy Center, Sana'a. 4- Raise the awareness of involved people (decision makers, family members etc…) to the importance of rehabilitating this group of people.
Key words:
aphasia, Broca’s area, Wernick’s area, Hemsphere :
1
1- Theoretical background 1-1- Definition of aphasia Language in general is a very complicated system. It has different components. People use these components skillfully to produce and understand linguistic messages. Physiologically, if we ask the common people where the ability to use langue is located? They will answer it is in the brain, but where and how in the brain? They have no answer for that. In order to provide a more specific answer, we have to turn to the work done in neurolinguistics. Neurolinguistics is a branch of linguistics that studies the relationship between language and the brain. The neurolinguists confirm that not all parts of the brain are in charge of controlling the language production/performance and comprehension. The brain has two parts, the left hemisphere and the right hemisphere. If we put the right hemisphere aside and concentrate on the left one, we find that language functions are located in the left hemisphere (Geschwind 1991). Aphasia may occur because of a brain injury, a stroke or degeneration. It involves the left cerebral hemisphere to a greater extent than the right one. Language function lateralizes to the left hemisphere in 96-99% of right-handed people and 60% of left-handed people. Of the remaining left-handed people, about one half have mixed hemisphere language dominance, and about one half have right hemisphere dominance. Left-handed individuals may develop aphasia after a lesion of either hemisphere, but the syndromes from left hemisphere injury may be milder or more selective than those seen in right-handed people (Kirshner and Jacobs 2009). 1-2- What causes aphasia? The researcher asked the neurologist and neurosurgeon about the causes of Aphasia. He answered that aphasia is caused by damage to one or more of the language areas in the brain. Many times, the cause of the brain injury is a stroke. A stroke occurs when blood is unable to reach a part of the brain. Brain cells die when they do not receive their normal supply of blood, which carries oxygen and important nutrients. Other causes of brain injury are severe blows of blood to the head, brain tumors, brain infections and other conditions that affect the brain. 1-3- How is aphasia diagnosed? The neurologist and neurosurgeon confirm that aphasia is firstly recognized by the neurologist who treats the person for his/her brain injury. The physician typically performs tests that require the person to follow commands, answer questions, name objects, and carry on a conversation. If the physician suspects aphasia, the patient is often referred to a speech-language pathologist, who performs a comprehensive examination of the person’s communication abilities. The examination includes the person’s ability to speak, express ideas, converse socially, understand language, read, and write, as well as the ability to swallow and to use alternative and argumentative communication.
2
1-4-How is aphasia treated? The researcher asked the neurologist, neurosurgeon and the speech therapists about the procedures to treat aphasic people. The neurologist said that in some cases, a person will completely recover from aphasia without treatment. This type of spontaneous recovery usually occurs following a type of stroke in which blood which flows to the brain is temporarily interrupted but quickly restored. This is called a transient ischemic attack. In these circumstances, language abilities may return in a few hours or a few days. He added that for most cases, language recovery is not as quick or as complete. While many people with aphasia experience partial spontaneous recovery, in which some language abilities return a few days to a month after the brain injury, some amount of aphasia typically remains. In these instances, speech-language therapy is often helpful. We asked the speech therapists the same question. They confirmed that linguistic recovery usually continues over a two-year period. Many health professionals believe that the most effective treatment begins early in the recovery process. Some of the factors that influence the amount of improvement include the cause of the brain damage, the area of the brain that was damaged, the extent of the brain injury, and the age and health of the individual. Additional factors include motivation, and family educational level. Aphasia therapy aims to improve a person’s ability to communicate by helping him/her to use remaining language abilities, restoring language abilities as much as possible, compensating for language problems, and learning other methods of communicating. Individual therapy focuses on the specific needs of the person, while group therapy offers the opportunity to use new communication skills in a small-group setting. They said that there are stroke clubs, regional support groups formed by people who have had a stroke, are available in most countries. These clubs also offer the opportunity for people with aphasia to try new communication skills. In addition, stroke clubs can help a person and his family adjusts to the life changes that accompany stroke and aphasia. We ask them about the role of families in treatment. They explained that the family involvement is often a crucial component of aphasia treatment so that the family members are taught the best way to communicate with their loved one. The Centre of Speech Therapy in Sana'a sometimes conducts courses for the family members of the patients. The experts in speech therapy teach them the house course of treatment. Family members are encouraged to:
Simplify language by using short, uncomplicated sentences. Repeat the content words or write down key words to clarify meaning as needed. Maintain a natural conversational manner appropriate for an adult. Minimize distractions, such as a loud radio or TV, whenever possible. Engage the person with aphasia in conversations.
3
Ask for and value the opinion of the person with aphasia, especially regarding family matters. Encourage any type of communication, whether it is speech, gesture, pointing, or drawing. Avoid correcting the person’s speech. Allow the person plenty of time to talk. Help the person become involved outside the home. Seek out support groups such as stroke clubs.
National Institute on Deafness and Other Communication Disorder (NIDCD) in U.S.A has the idea of using computers to improve the language abilities of people with aphasia. Studies have shown that computer-assisted therapy can help people with aphasia retrieve certain parts of speech, such as the use of verbs. Computers can also provide an alternative system of communication for people with difficulty expressing language. Lastly, computers can help people who have problems perceiving the difference between phonemes (the sounds from which words are formed) by providing auditory discrimination exercises. 1-5-AREAS OF THE LANGUAGE FUNCTION IN THE BRAIN
Shape (1) the different parts in brain that control speech functions (www. http://thebrain.mcgill.ca/flash/)
The shaded areas in the shape above refer to the exact location of language functions in the brain. The linguists and nerolinguists have come to know that these areas were known to have specific language disabilities. They found as well that the people, who have language disabilities, have damage in those specific areas of the brain. The two main and major areas that are responsible for language functions are known as Broca's area and Wernick'es area. The other two minor areas are totally affected by the damage of the main areas. These areas can be displayed as follows: 1-5-1 Broca's area (expressive aphasia)
4
Boeree (2004) said that Paul Broca is a French surgeon. He reported in 1960s that damage to this specific area which is located in the left hemisphere of the brain is related to an extreme difficulty in producing speech. He affirmed that damage to the exact area in the right hemisphere of the brain had no such effect. This finding was first used to argue that language ability must be located in the left hemisphere and since then it has been taken as more specifically illustrating that Broca's area is vitally involved in the production of speech. Patients with Broca's aphasia are individuals who know "what they want to say, they just cannot get it out. They are typically able to understand what is being said to them, but unable to fluently speak. This is also known as non-fluent aphasia. Some of other symptoms may include problems with fluency, articulation, wordfinding, word repetition, and producing and comprehending complex grammatical sentences, both orally and in writing. These characteristics distinguish them from other individuals with other types of aphasia. Other aphasia types may have more difficulty in understanding what is said to them. They may also struggle more with reading and writing than do individuals with Broca’s aphasia. While the individuals with Broca’s aphasia also have a good ability to self-monitor their language output, other types of aphasia may be more unaware of their language performance. Also, site of lesion (brain damaged area) differs between the different aphasias (Bradly 1979). The pictures below are set of tomographic images that show the brain of Broca's patients.
Shape (2) C.T. scan of Broca's aphasia (http://webspace.ship.edu/cgboer/speechbrain.html_
1-5-2-Wernicke's area (receptive aphasia) Carl Wernicke is a German physician. In 1970s, he reported that damage in this area of the brain results to difficulties in speech comprehension. The findings which Wernicke confirmed, beside the truth that the left hemisphere is the location of language ability, that Wernicke's area is part of the brain which is highly involved in the speech understanding. That is to say, the other name of language disorder which results in difficulties in auditory comprehension is 5
sometimes called "sensory aphasia" (Boeree 2004). Anyone who has damage in this area actually produce very fluent speech which is, however, often difficult to make sense of. Lesser and Milroy (1993) gave following example shows how the Wernicke's patient uses circumlocution to express the word "KITE". "it is blowing, in the right, and er there's four letters in it, and I think it begins with a C- goes- when you start it then goes right up in the air- I would I would have to keep racking my brain how to I would spell that word-that flies, that that doesn't fly, you pull it round, it goes up in the air". In short, the Broca's area and the Wernicke's area are the two faces of a coin. One area is responsible for language production and the other area is in charge of language comprehension (Yule 1997). The following set of tomographic pictures show the brain of a Wernicke's patient.
Shape(3) C.T. scan of Wernicke's area (http://webspace.ship.edu/cgboer/speechbrain.html
1-5-3-The Central Sulcus (Motor Cortex) The motor cortex controls the movement of the muscles ( the moving of head, hand, feet, arm…).The area of cortex which is close to the Broca's area is the part that controls the articulatroy muscles of the face, jaw, tongue and larynx. This is the evidence that this area is involved in the actual physical articulation of speech. Robert and Penficd (1959) are two researchers. They applied electrical current to this area of the brain with some people. They found after this experiment that the speech production was not normal and affected negatively. In other words, the muscles of organs of speech became loose and consequently no exact language articulation is produced. Shape (4) below is a more detailed picture of the strip, showing what is sometimes called the motor cortex area, which is a depiction of how motor functions are localized along the motor strip. The portion adjacent to Broca's area controls the muscles of the face and mouth which are our main concern in this research. .
6
Shape (4) http://webspace.ship.edu/cgboer/speechbrain.html
1-5-4-Arcuate Fasciculus The bundle of nerve fibers called the Arcuate Fasciulus. This area which was discovered by Wernicke connects between the Broca's area and Wernicke's area. It is concluded that these four areas in the brain are in charge of language performance, i.e. they follow a definite pattern and are involved in hearing words, understanding them, and then saying them. Firstly, the words are heard and comprehended through the Wernicke's area. Then these signs are transferred via the Arcuate Fascilulus to the Broca's area where preparation is made to produce it. This signal is then sent to the Motor cortex. The motor cortex sends signs to the muscles of speech organs to physically articulate the words. 1-6-The Brain and Communication As said earlier that the language's functions totally exist in the brain. There are specific areas involved in speech production and speech comprehension. Beside the main parts which are discussed above, the shapes below, which are credited to Dr. Eric Chudler (2008) display more parts which are important in pronouncing words that are heard and words that are read. 1-6-1- How to speak a word that is heard
7
Shape (5) Areas of language function http://library.thinkquest.org/26451/contents/spokenword/thebrainandcommunication.m
To speak a word that is heard, information must first get to the primary auditory cortex. From the primary auditory cortex, information is transmitted to the posterior speech area, including Wernicke's area. From Wernicke's area, information travels to Broca's area, then to the Primary Motor Cortex. 1-6-2- How to speak a word that is read
Shape (6) Areas of language function (ibid)
To speak a word that is read, information must first get to the primary visual cortex. From the primary visual cortex, information is transmitted to the posterior speech area, including Wernicke's area. From Wernicke's area, information travels to Broca's area, then to the Primary Motor Cortex. For example when some one says "good morning", the sounds acoustically move form the speaker's mouth to the listener's ear in a form of signals. The hearing nerves transfer the signals to Wernicke's area. The wernicke's area comprehends the meaning of signals. Then it sends the words to Broca's area through arcuate fasciulus. The Broca's area sends signals to the motor cortex, which controls the movement of the speech organs muscles, to verbally respond by saying "good morning". The diagram below explains this process.
8
. Shape (7) process of circulating speech between hearer and speaker .(www.http://thebrain.mcgill.ca/flash/d/d_10/d_10_cr/d_10_cr_lan/d_10_cr_lan.ht ml)
7-Symptoms of the Aphasia Spreen, & Risser (2003) state that the neuroloinguists generally found that the people with aphasia may experience any of the following behaviors due to an acquired brain injury. - inability to comprehend language - inability to pronounce - inability to speak spontaneously - inability to form word - inability to name objects - excessive creation and use of personal neologisms - inability to repeat phrase - persistent repetition of phrases - incomplete sentences - inability to read - inability to write According to such symptoms, the researcher selects randomly 75 cases as samples of retarded people out of 120 aphasic cases who are under the course of study in the Speech Therapy Centre, Sana'a. He tries to concentrate on some linguistic issues that are relevant to language functions in the brain such as: 1- The linguistic symptoms of the impairment. 2-The researcher has many sessions with the neurologist and neurosurgery. Through the set of tomographic pictures of different Broca's and Wernicke's syndrome brain (C.T. Scans) of some cases, we specify the exact damaged areas in the brain which cause the language defects. 3- The researcher had interviewed some speech therapists. According to their experience, he tries to list the steps they follow to rehabilitate the language of retarded people with the different aphasic cases. The cases under study are grouped under four main categories. The first category consists of 35 aphasic cases. All have problems in language production. The 9
second category is 25 cases. They have problems in language comprehension. The third one is 10 cases. They have problems in both language production and language comprehension. The fourth category is 5 cases. They have minor problems in the muscles of speech organs because of a defect in motor cortex area in the brain. The ages of cases vary between 6 to 63 years old. The damages in the brain for all cases are resulted from stroke, injury or accident. The researcher tries his best to consult the neurologists, neurosurgery and speech therapists in each step of this research to guarantee the accuracy, make it scientific and involve those who are experts in this field. Below the categories of aphasic people are analyzed under the three main points. 2-Practical study: 2-1- The first category (35 cases) The patients of this category have problems in the Broca's area because the physical features they suffer from are resulted from a deficiency in this area. The patients with Broca's and motor cortex areas share, to some extent, the same features. However, any defect in the Broca' area affects the functions of the motor cortex and not vice versa. The symptoms of these cases are: 1- The patients have right hemi-paresis, meaning that there can be paralysis of the patients' right face and arm. 2- They are unable to utter words. 3- They always salivate. 4- They cannot swallow properly. 5- They have difficulties to move their lips and tongue. 6- When they talk they omit small words. 7-They understand the speech of others to varying degrees. Because of this they are aware of their difficulties and can become easily frustrated by their speaking problems. 2-1-1- Treatment The speech therapists start the treatment by making massage for the faces and lips of the patients. Then they give them gum to chew and let them suck juice with strew, noodles, sugar, and salt. Then for eating, they are given some hard fruits and vegetables to activate the muscles of the speech organs. The teachers concentrate on asking the patients to blow the balloon and extinguish the candle. The patients practice producing sounds that move their lower jaws like ( وا – ﯾﺎ-)ا. The speech therapists act in front of the patients. They take their tongues out, rolls them up and down, then they shift the tongues to different sides inside the mouth and the patients repeat the same actions many times. To make the lips stronger, the patients are asked to hold a pen by their lips. Such activities are preparatory steps before teaching the patients how to produce the linguistic items. The second task regarding speech production is that the patients are taught how to produce only sounds, then units of a word, then words and sentences. The speech therapists passed all these steps successfully with most of the regular cases. They now teach them how to produce sentences. The psychological states of the patients before the course of rehabilitation were not good. They lost self confidence. Now as the teachers say, the patients are in
10
good mood and they are optimistic especially after controlling the saliva, producing the words, and naming the things. 2-2- The second category (25 cases) The patients of this category are suffering from damage in the brain because of a stroke or injury in. This damage affected Wernick's area. As a result, the patients generally have problems in language comprehension. They generally carry the following symptoms: 1-They are unable to comprehend the names of things properly. 2-They use long sentences that have no meaning, add unnecessary words and even create new words (neologisms) 3-They have poor auditory and comprehension 4-They have difficulties in understanding the speech of themselves and others and therefore they are unaware of their mistakes. 2-2-1-Treatment The speech therapists follow certain techniques to rehabilitate such cases. They firstly re-construct the language forms in the mind of the patients. They show the things to the patients and name them individually. The patients repeat the names they hear many times. With the passage of the course, most of the patients are able to name the things properly. After this, the therapists start teaching them how to connect words to make meaningful phrases and sentences. We notice that with all cases, the physical exercises for the speech organs are important to stimulate them. Most of the exercises are centered on the jaws, lips and tongue like using lollypop, chewing gum, holding pen by using lips, sucking noodles etc. The therapists are activating the patients' memories by making daily evaluation for what they are taught before. 2-3- The third category (10 cases) In this group, the patients are not able to move their organs of speech. As a result they have the following symptoms: 1-The patients cannot control their saliva. 2-They have difficulties in speech production (sounds, words, sentences) 3-They cannot eat properly except soft food and juice. 4-They cannot chew food. The patients physically have problems in a part of the motor cortex area which is near Broca's area in the brain. This area is responsible for the movement of the muscles of organs of speech. So, any damage there results such impairment. Psychologically, before the treatment, the aphasic children used to cry hysterically. But after the treatment, they become psychologically settled and have self confidence. 2-3-1 Treatment The speech therapists universally suggest some procedures that help patients to activate and stimulate the muscles of their organs of speech. I asked them about these cases. They said that this case is treatable. In the first task, the patients will show improvement, if they are put under extensive course of rehabilitation. This course lasts for one year minimally. The speech therapists do daily massage for the faces, lips and cheeks of the patients. They ask them to suck juice by using strew. They put bifk (salty and spongy snack) in their mouths to let the tongue
11
move to swallow the saliva. They recommend sucking noodles in order to practice rounding the lips. They ask him to chew gum as long as he can, blow the balloons and extinguish the candles from different distance. Then the patients are given some hard vegetables and fruits like cucumber, carrot, apples etc, to eat. Such activities stimulate the motor cortex to activate the muscles of speech organs to work. In the second task, the patients are asked to produce words. They are asked to repeat the sounds of a word. For example, the word (""ﺟﻤﻞ/ djamal? (camel)) is divided into three units ( ل- ﻣ ﺎ- ﺟ ﺎ, /dj-ma-l/ ). They are practiced to repeat each unit several times. Then, the whole word is given to them. With repetition, they will be able to produce the whole word correctly. Similarly, with the word (" "طﯿﺎره/tayarah/ airplane), it is divided into three units ( ره- ﯾﺎ- ﺗﺎ- /ta-ya-rah/. With repetition, the patients will pronounce it properly. The sound ( )طاis changed into ( )ﺗ ﺎbecause it is easier for the patients to articulate. Now the patients are in different degrees of progress. The speech therapists declared that most of the patients are in the phase of articulating words and phrase. They added that this is a good performance for them. 2-4- The fourth category (5 cases) The cases of this group are the most chronic. The patients are suffering form defects in the two main areas (Broca and wernick's areas). This kind of aphasia is called global aphasia. That means the main areas of language functions in the brain are damaged. Global aphasia is almost a total impairment of all the language modalities (i.e., speaking, writing, reading, and listening. The patients of this group carry the following symptoms: 1-The patients are not able to produce language (words, phrases and sentences). 2-The patients cannot move their organs of speech. 3-They always salivate. 4-They cannot repeat the names of things. 5-They have poor auditory and comprehension. 6-They do not understand what they are told. 7- They have sensory deficits.
2-4-1-Treatment The speech therapists generally agree on the idea that the patients of this aphasia are not easily treatable. Most of the cases do not show any progress. They generally do not live long. Out of the five cases, two cases passed away. However, the speech therapists try to give them courses for their double impairment. They use the treatment techniques of Broca and Wrnicke's aphasia together.
3-Conclusion There are specific areas, in the left hemisphere of the brain, shoulder the responsibilities of language functions. Any damage in one of these areas creates language impairment (aphasia). If a stroke happens in the area called Broka, the patient will suffer from being not able to produce language. Such aphasia is called expressive aphasia. On the other hand, those who have problem in the language comprehension are considered to have problem in the wernicke's area which is called receptive aphasia. However, there are people whose two main
12
areas of language function (Broca and Wernicke) are damaged. Their case is called global aphasia. Some aphasic people have defect in an area called motor cortex. This problem affects the functions of the speech organs' muscles. A more elaborated taxonomy in the table (1) below shows the relationship of four named aphasic syndromes to six general types of symptoms. The table (2) shows the percentage of retarded people with different type of aphasia in the Speech Therapy Centre, Sana'a, Yemen Republic. Symptoms -----------Aphasia
Fluent
Repetition
Comprehension Naming
Right- side sensory Hemiplga deficits
Broca
No
Poor
Good
Poor
Yes
Few
Wernick
Yes
Poor
Poor
Poor
No
Some
Global
No
Poor
Poor
Poor
Yes
Yes
Transcorti -cal motor
No
Good
Good
Poor
Some
No
Table (1)
Table (2)
The neurologist and the neurosurgeon saw the set pictures of tomographic images that show the brain of Broca's and wernicke's patients. They said that the circled areas in left hemisphere of the images, which are dark in color, are the damaged areas that cause aphasia (see shapes 2-3). They affirmed that these areas have dead muscles thus they are seen dark in color.
13
I try to list down the steps which are used by the speech therapists to rehabilitate the aphasic people. They adopt specific and scientific methods of treatment for each kind of aphasia. They said that they apply the same techniques used globally and they are satisfied with the performance they achieved though of financial and academic difficulties. The families of the aphasic members and the decision makers should be indulged in the different steps of treatment. They help a lot in accelerating the course of treatment. The family members should know that the patient needs special physical and psychological care. The decision makers should bridge the financial and academic gap the speech therapy centers have.
4-Recommendations The researcher has come our with some recommendations that help rehabilitate well the aphasic people in the Speech Therapy Center, Sana'a, Yemen Republic. 1- The government should increase the number of speech Therapist Centers not only in Sana'a but in all governorates to rehabilitate a large number of retarded people. 2- All the speech therapy centers should have not only speech therapists but psycho-therapists and physio-therapists as well. This team will rehabilitate the patients psychologically, physiologically and socially alike. 3- Regular courses for speech therapists should be organized to update their knowledge in the field and teach them how to use the computer programs as a course of treatment. 4- Regular courses for the family members of the patients should be held in order to link the course of the center with the families' activities in the house to complete the course of the center.
*Remarks of Thanks to: 1-Speech Therapists: (National Centre of Speech Therapy, Sana'a, Yemen) 1-T/ Maha AlQadasi 2-T/ Eyman AlQada 3-T/ Firdos Qamel 2- Neurologists: 1- Dr. Ali Abdulatif (German Saudi Hospital) 3- Neurosurgeon 1- Dr. Abdulghani Nasher (German Saudi Hospital)
14
*References 1-Boeree,G.(2004) Speech and http://webspace.ship.edu/cgboer/speechbrain.html
Brain.
In
2-Bradley , D C. & etal (1979) Syntactic deficits in Broca's aphasia. In Caplan, D (ed) 1979: 269-286. 3-Caplan, D (1979) Biological studies of mental processes. Cambridge, Mass: MIT press 4Chudler, E.(2008) Brain and communication. In http://library.thinkquest.org/26451/contents/spokenword/thebrainandcommunica tion.htm) 5 -Geschwind, N. (1991) Specializations of human brain. In Wang (ed) 1919: 25-34. 6- Kirshner, H. S and Jacobs D. H. (2009) Aphasia. In http:// aphasia/Aphasia eMedicine Neurology. 7- Lesser,R. and Milory,l. (1993) linguistics and aphasia. Longman. 8-Penifield,W& Robert,L.(1959) Speech and brain mechanism. Princeton University Press. 9-Spreen, O. & Risser, A.H. (2003) Assessment of Aphasia. New York: Oxford University Press 10- Wang. W.S. Y. (ed) (1991) The emergence of language development and evolution: W.H Freeman. 11- Yule, G (1997) The study of language. Cambridge University press: UK.
15
