Acquired Brain Injury E-Book

Kevin Foy

• Herausgeber: WS
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 276

Veröffentlichungsjahr: 2022

Beschreibung

Tens of millions live with the long-term consequences of acquired brain injury. It has life changing and frequently devastating effects on the individual's physical, cognitive, behavioural, and emotional well-being. As well as causing huge challenges and stresses for family and friends.

Acquired Brain Injury: A Guide for Families and Survivors accessibly discusses acquired brain injuries in detail for those individuals and families affected.

Written by experienced neuropsychiatrist Dr Kevin Foy, the book seamlessly guides the reader through the different types of brain injury, and their effects, as well as the various stages of recovery. Offering facts and advice from the initial trauma all the way through to long-term care, Dr Foy provides the tools to help deal with the challenges that may lie ahead.

Leseprobe

ACQUIRED

BRAIN INJURY

A Guide for Families and Survivors

Dr Kevin Foy

Copyright © Kevin Foy 2020

The author’s moral rights have been asserted.

All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without prior written permission from the publisher.

Names and identifying details used in case studies have been changed to protect the privacy of individuals.

Figures 1–3, 5, 6, 8, 9: illustrations by Andriy Achyn

Published in 2020 by Ockham Publishing in the United Kingdom

ISBN 978-1-83919-029-2

Cover design by Claire Wood

www.ockham-publishing.com

Dedicated to my patients, colleagues and friends at the Walton Centre with gratitude for everything.

Bridges linking the past and future

old friends passing though with us still.

– Brendan Kennelly, Begin

About the Author

Dr Kevin Foy qualified as a doctor from University College Dublin. At an early stage of his training, he developed an interest in the management of patients with acquired brain injury and neuropsychiatric disorders. He trained in psychiatry, obtaining membership of the Royal College of Psychiatrists before spending time training in neurology and obtaining membership of the Royal College of Physicians of Ireland. He completed a Master of Science in Clinical Neuropsychiatry from the University of Birmingham. In 2010, he was awarded a prestigious Doctor Steveen’s Scholarship from the Irish Department of Health and spent a year training in the National Hospital for Neurology and Neurosurgery, Queen Square in London. There he worked as a Clinical Fellow in neuropsychiatry and treated patients with diverse neuropsychiatric disease including early onset dementia, Parkinson’s disease, Huntington’s disease and conversion/psychosomatic disorders.

Since 2011, he has worked as a consultant neuropsychiatrist in Liverpool. Initially he was consultant neuropsychiatrist at the Brain Injury Rehabilitation Centre in Mossley Hill Hospital where he treated individuals with cognitive, behavioural and emotional problems after moderate to severe acquired Brain Injury.

He has also worked at the Walton Centre since 2011 and since 2015 has worked there full time. In the Walton Centre, he assesses and treat patients in tertiary general neuropsychiatry clinics as well as inpatients. He also assesses and manages the inpatients on the three rehabilitation units associated with the Cheshire and Merseyside Rehabilitation and Reablement Network. He has recently started working as a consultant neuropsychiatrist at Bloomfield Health Services, Dublin.

Dr Foy is a national executive committee member of the Faculty of Neuropsychiatry at the Royal College of Psychiatrists. He is the regional specialty representative for neuropsychiatry at the Northern division of the Royal College of Psychiatry. He is also an honorary clinical lecturer at the University of Liverpool and is a visiting lecturer to University of Birmingham.

Contents

Introductioni

Chapter One1

Welcome to the Brain

Chapter Two15

What is a Brain Injury?

Chapter Three26

Acquired Brain Injury: The Silent Epidemic

Chapter Four31

Mild, Moderate or Severe?

Chapter Five34

Investigations and Tests

Chapter Six37

Neurosurgery and Initial Inpatient Care

Chapter Seven41

Rehabilitation: A Multidisciplinary Journey

Chapter Eight48

Inpatient rehabilitation

Chapter Nine59

Unconsciousness, Coma, Low Awareness

Chapter Ten68

Post-traumatic Amnesia (PTA)

Chapter Eleven73

Physical Problems after a Brain Injury

Chapter Twelve95

Mental Health Problems After A Brain Injury

Chapter Thirteen117

Walking on Eggshells for Dr Jekyll: The Organic Personality Disorder

Chapter Fourteen137

Post-concussion Syndrome

Chapter Fifteen143

Stages in Response to Trauma: Coping as a family

Chapter Sixteen152

Frequently Asked Questions

Chapter Seventeen158

Winning the War: Practical Solutions to Maximising Recovery Potential

Afterword171

Sources of support172

Glossary174

Introduction

Looking back, throughout my childhood and life, I’ve known countless relatives, neighbours and friends who have suffered an acquired brain injury. At the time, I didn’t realise the depth of the struggles and battles they faced on a daily basis. Nobody else seemed to notice either. We all collectively turned a blind eye and looked the other way. We blamed any challenges they had on their idiosyncrasies and disregarded the fact that they had a brain injury.

Acquired brain injury (ABI) is a condition that is far more common in the community than is often realised. Over a million people in the United Kingdom struggle with the long-term consequences of a brain injury. Most of us know individuals who have sustained head injuries or had a brain haemorrhage. Despite this, knowledge about the consequences of the condition is limited among the general public. Even in medical school, I recall little training about ABI. I recall even less in post-graduate training in psychiatry and neurology. In many respects, this is because ABI is, for the most part, a hidden disability and one that doesn’t impose upon our consciousness or daily cares. We tend to think erroneously that an individual with a brain injury is somehow fully recovered and back to their old selves when they are discharged from hospital. The day-to-day consequences of acquired brain injury are by and large hidden disabilities, hidden frustrations and hidden sorrows only recognised and experienced by the survivor themselves and their close loved ones.

My own training in relation to the devastating consequences of ABI only really began when I started working as a consultant at both the Merseycare Brain Injury Rehabilitation Unit and at the Walton Centre for Neurology and Neurosurgery in 2011. In both roles, I got the opportunity to learn the complexities of brain injury from my patients and their families.

As a consultant neuropsychiatrist within the Cheshire and Merseyside Rehabilitation Pathway, I have gotten the opportunity to see the journey that an individual and their family makes from the time of the car crash, assault or bleed to their progression within hospital, rehabilitation unit and the community. One of the reasons for writing this book is that the information out there on the internet and in other sources is highly variable; some is frankly incorrect; some is overly optimistic; and some is overly pessimistic.

I hope that this book will give family members and the survivor of ABI a good overview about the condition. I will describe the effects of a brain injury on the brain and body and ultimately how it affects the individual in terms of their memory and cognitive abilities, their mood and their behaviour. I hope this book will also give family members and friends of individuals with a brain injury advice on how to cope with and manage potential challenges in the immediate and longer term.

The first chapters will aim to provide a concise and easy-to-understand overview about the human brain and the various types and severity of brain injuries. Later chapters will look at inpatient care both within the hospital, and rehabilitation units and community care. The physical and mental health consequences of ABI are discussed later in the book, along with specific advice for family members on how to manage such challenges. Throughout the book I’ll use illustrative case histories to describe real-world examples of the kind of challenges encountered.

My hope is that survivors and their loved ones can dip in and out of the book and develop a better understanding of the difficulties after a brain injury, and get advice on the potential solutions.

Chapter One

Welcome to the Brain

In the fourth century B.C., Hippocrates of Cos, the father of medicine, described the brain as the site from which “arise our pleasures, joy, laughter and jests, as well as our sorrows, pains, griefs and tears”. The human brain is the organ that has led us to walking on the moon and exploring the darkest regions of the universe. The complexity of the brain is awe-inspiring and difficult to contemplate or, for that matter, attempt to summarise in a short chapter. To describe the brain as a computer is to do it a disservice and minimise the complexity of its functions.

The Neuron in a Nutshell

Figure 1: The Neuron

The human brain is essentially a collection of microscopic cells called neurons, with blood vessels and other cells to support them. A neuron is unimaginably small and consists of a headquarters, the nerve cell body and a far smaller cable-like axon that connects it to other nerves and other parts of the body. The nerve cell body can vary in size from 0.004 mm to 0.1 mm – meaning you could fit between one and twenty-five neuron cell bodies side by side across the width of a single human hair. The axon which emerges from the neuron can vary greatly in length, the longest being over three feet long. The diameter of an axon is even smaller at just 0.001 mm or one hundredth the diameter of a human hair. In a similar way that electrical cable is insulated, some axons are covered by a fatty layer called myelin. Myelin functions to speed up the transmission of information through the axon.

Just like people, a neuron is interested in information. The brain can most easily be imagined as being like a very crowded room of people at a party or social gathering. In the case of the brain there are 100 billion neurons and a further ten times that number of cells supporting the individual nerve cells. The supporting cells are called glial cells, and a bit like waiters at a party they support the neurons with nutrients and protection.

Just like party guests, a neuron gets information from many sources – some of which are close in proximity and others which come from further afield such from the foot, hands, eyes, ears, or other sense organs. Whilst each individual guest at a party might have a relatively limited selection of people with whom they communicate, the average neuron has 7,000 connections, also called synapses. And just like a tittle-tattler, the neuron processes such information and sends it to another neuron, or neurons, within microseconds. These other neurons can be located in the brain or the spinal cord. Some people are quite positive and cause other people to laugh or get excited whilst other individuals are negative and depress others – similarly neurons may either be inhibitory and stop other neurons from firing or they can be excitatory and make them fire.

At its most basic, nerve cells communicate with each other through electrical signals. As such, the brain is like an electrical appliance with the electricity flowing along cables – the axons.

The neuron has a different concentration of chemical elements, such as sodium, potassium, and calcium, inside than outside. Just like the ends of a battery, these chemicals all have an electrical charge – either positive or negative. This means that the electrical charge inside the nerve cell is different to that outside. The difference in charge is partly due to pumps within the wall of the neuron that actively pump some chemicals in and others out. Those pumps are switched on or off in response to minute quantities of substances called neurotransmitters which are produced at the end of the axon. The neurotransmitter is secreted into the gap between the neurons and binds to targets on the other neuron causing the pumps in the other neuron to either pump or not pump. The action of the pumps causes the concentration of chemicals and electrical charge within the neuron to suddenly change. Just like a row of dominos falling one by one, the change in the electrical charge moves like a wave down the neuron to the end of the axon, where it stimulates the release of neurotransmitters that cross the gap between neurons and affect the next neuron.

In the same way that at a party, different groups of people will be discussing different things in different parts of the room, different parts of the brain are similarly interested in different functions. Those various parts are linked to each other by the cables of axons that run deep within the brain.

Figure Two: Side View of the Brain

The Brain

The human brain consists of the cerebrum, cerebellum and brain stem. It weighs about 1.5 kg or just over 3 pounds. The cerebrum is the largest part of the brain and is located on the top and in front of the much smaller cerebellum and brain stem. Despite appearing quite solid in photographs or when shown on television documentaries, the cerebrum has the consistency of cold porridge or tofu. It looks a little like a cauliflower with lots of grooves called sulci and elongated bumps called gyri. Scientists and doctors use these grooves and bumps as landmarks when looking at brain scans, completing surgery or when testing how the brain is functioning.

The cerebrum is divided into two halves or hemispheres – one on the left and one on the right. Both hemispheres are connected through a band of tissue called the corpus callosum that lies deep within the brain. Whilst at first glance both hemispheres are mirror images of each other, there are subtle differences particularly in terms of specialised functions. The parts of the brain that have a role in understanding speech and speaking are located on the left in most people. The right side of the brain has an important role in the use of non-verbal information and appears to have a role in taking note of the bigger picture and looking for patterns.

At the back of the brain lies a knob of brain tissue that looks like a miniature brain or a floret of cauliflower glued on. That miniature brain is called the cerebellum and has important roles in controlling movement.

The brain stem is located between the spinal cord and the cerebrum. This part of the brain is vital for the life-supporting systems of the body that control breathing and other essential functions. Damage to this part of the brain is often devastating and causes death.

Figure Three: The Spinal Cord

The Cerebrum

As we just introduced, the cerebrum is the main bulk of the brain and sits on top of the brain stem. Each hemisphere is divided into four different lobes which are named after the parts of the skull that cover it: the parietal lobe, the temporal lobe, the occipital lobe and the frontal lobe. Each lobe is associated with performing different functions, and damage to each lobe is associated with differing problems.

Figure Four: Lobes of the Brain

The temporal lobe is located approximately at the level of the temples and just in front of the ear. It has a number of functions including processing sound information. It also has a role in memory formation. Damage to the temporal lobes can, in some cases, be associated with certain forms of epilepsy.

The parietal lobe sits just above the temporal lobe. This part of the brain receives information from the various sensory organs that are located throughout the body. As a result, this part of the brain processes and integrates information pertaining to touch, pain, temperature of objects and position of parts of the body in space. This information can be used by other regions of the brain, such as the movement centres in the frontal lobe telling a limb to move away from a source of pain.

The parietal lobe also has a role in spatial awareness. Damage of it can lead to sensory neglect meaning that the brain ignores information coming from one part of the body and the individual can end up repeatedly bumping that side of their body.

The occipital lobe is located at the back of the skull. This area receives information from the retina of the eyes and uses the visual information to process and recognise what is in front of the individual. Damage to this part of the brain is associated with different types of blindness.

The Frontal Lobes

The frontal lobes are found at the front of the brain and are especially large in humans, accounting for over 35% of the volume of the whole brain. In comparison, animals have smaller frontal lobes. For example, in dogs the frontal lobe only comprises 7% of the total volume of the brain.

The frontal lobe is divided into the motor cortex, which controls movement, and the pre-frontal cortex, which has important roles in personality, motivation and cognition.

The motor cortex is located towards the back of the frontal lobe and borders the parietal lobe. It makes sense that it is close to the parietal lobe given that movement requires a lot of sensory information. Even though at the level of the naked eye, the strip-like motor cortex all looks the same, its neurons are arranged according to the part of the body they control. Areas of the body that require a lot of precise and delicate movements such as the fingers require far greater control and so have more neurons in the cortex. The areas of the motor cortex that control movement of the mouth and lips is also large given the role the mouth has in communication. The right side of the body is controlled from the left motor cortex and left side is controlled from the right motor cortex. People who write with their right hand are said to have a dominant left hemisphere. Damage to parts of the left motor cortex can profoundly affect speech and the individual’s ability to speak. In contrast, damage to the right motor cortex is typically associated with more subtle language changes such as intonation of voice.

The pre-frontal cortex lies in front of the motor cortex. It is the front driving seat of the brain. This part of the brain has very important roles in personality, motivation, social function and cognition. Damage to it can be associated with dramatic changes of personality. This part of the frontal lobe is highly connected with the rest of the brain. As a result, it functions as a supervisor and has an important role in management and organisation. Damage to the frontal lobe is therefore associated with an individual becoming much more disorganised and chaotic – both in terms of their behaviour and also in terms of their ability to memorise things. Through connections with the brainstem, it has an important role in wakefulness. An individual with severe damage to their frontal lobe can present as extremely apathetic and unmotivated.

The frontal lobe is the last part of the brain to develop and fully mature and doesn’t stop until the early twenties. Young adults, teenagers and children therefore go around with an immature frontal lobe. This can be readily seen in a school playground or classroom. Younger children can be impulsive in their actions and often take risks without thoughts of the potential consequences. Similarly, they can be blunt in what they say and lack the diplomacy and tact that is supposed to be associated with adulthood. They may also be a little less empathic and sensitive to the needs, desires and feelings of others. Their ability to control their temper can also be less strong than is expected in adults. Similarly, their ability to control their emotions is less robust than in adults – younger children can readily laugh or cry and experience a roller coaster of emotions on a daily basis. All of this is due to the fact that the frontal lobes act as a brake to stop socially inappropriate behaviour. When someone’s frontal lobe is damaged, that braking mechanism is affected with quite often significant consequences for how the individual behaves.

The Spinal Cord

The spinal cord descends out of the brain like a long tail. The cord is the thickness of a finger and it starts at the bottom of the skull and is protected by the individual bones of the back which encircle it. The back itself consists of over 24 bones or vertebrae, divided into cervical, thoracic, lumbar, sacral and coccygeal vertebrae. Between the junction of each of the vertebrae, individual string-like nerves emerge out of the spinal cord and break up to supply muscles with information from the brain and carry information back to the brain from sense organs – for example from nerve endings in the skin or joints.

If a telephone cable is cut the message doesn’t get through. In a similar way, if the spinal cord is cut, damaged or is starved of blood at any of those various levels information coming from the brain to muscles or to the brain from skin etc. is lost and the person presents with symptoms of paralysis. Complete damage to the spinal cord in the neck is associated with paralysis of all four limbs, also called quadriparesis or tetraparesis. Damage to the spinal cord below the neck is associated with paralysis of the legs.

Blood Supply and the Brain

The brain receives a huge proportion of the blood supply pumped from the heart. Despite the fact that it weighs less than 2% of the total bodyweight, it receives 15% of the blood being pumped from the heart in every beat. Every minute the brain receives the equivalent of 750 mls of blood – that’s two and a half soda cans of blood in a minute and 136 cans’ worth in an hour. The reason why the blood supply is so high is because the nerve cells within the brain need a lot of oxygen and sugar to keep functioning. Whilst other parts of the body can cope with temporary reductions in blood supply, the brain copes badly with scarcity. Individual nerve cells and parts of the brain are irreparably damaged if there is a loss of blood supply for more than three minutes. One of the parts of the brain which is most sensitive to a lack of oxygen is the hippocampus – the part concerned with taking in information and encoding it to form short-term memory. This is found deep in the temporal lobe. Even quite short periods of loss of blood supply, such as that seen in a cardiac arrest, is enough to irreparably damage this part of the brain causing severe memory problems. The affected individual may be physically quite well after their cardiac arrest and be able to walk and talk but have no ability to recall what is going on in their lives.

As a result of its high requirements for food and oxygen, the brain has a very extensive supply of blood vessels to deliver nutrients and oxygen-rich blood from the heart. The network of blood vessels is more complicated than many other organs of the body and the actual anatomy can vary quite a lot from individual to individual.

Protecting the Brain

Bangs to the head are not uncommon. Young children in particular continually fall and play games that risks head trauma. We all have accidentally hit our heads – be it when passing under a low wooden beam or when going up into the loft. This is to say nothing of the knocks to the head when playing football, rugby or other sports. The great miracle of life is why brain injuries aren’t more common. Yet if knocks to the head are commonplace now, the frequency of bangs to the head was far more common in history when individuals worked on farms or factories that had little consideration of health and safety. All things considered, humans and other mammals couldn’t have been able to evolve without the evolution developing significant protective mechanisms for the brain.

The Skull

The skull, an armour-like protective layer of bone, is a masterpiece of design and engineering. Whilst it is easy to think of the skull as a single bone, it is in fact composed of at least 22 different bones. These bones are fused together, however that fusion doesn’t take place until after birth so that the skull can move as it descends through the birth canal when a baby is being born. Within the skull are a number of spaces called sinuses which are air-filled cavities rather than solid bone; the effect of having sinuses means that the head is lighter. Bone itself is incredibly strong – stronger than concrete. The construction of the head itself means that the mid-face and sinuses may act as a kind of crumple zone or relative cushion for protecting the brain.

The Meninges

The brain is protected by three layers that can be compared to bedding on a bed. The innermost layer – similar to a fitted sheet – is called the pia mater (which literally means ‘tender mother’). This very delicate and fine spider web-like layer covers the surface of the brain. It is pierced by very small blood vessels called capillaries but otherwise it is impermeable and it seals the brain off and acts like a wax jacket. It has a role in maintaining the blood–brain barrier and isolating the brain from the body so that the nerves within the brain can exist in a delicate environment where chemicals are at a different concentration to the rest of the body. 

Figure Five: The Meninges

The arachnoid mater is the next layer just above the pia mater. This layer contains the blood vessels, small capillary branches of which divide off and penetrate deeper into the brain. If the pia mater could be considered to be a fitted sheet, the arachnoid mater is best thought of as a bedsheet on top of it. The space between both layers is called the sub-arachnoid layer and is the site where blood collects if a blood vessel bursts, say, as a result of an aneurysm. Normally this layer is bathed in a fine colourless fluid called cerebrospinal fluid.

The outer protective blanket-like layer is called the dura mater, a term derived from Latin and literally meaning ‘hard mother’. This layer is very tough and is partly fused to the inside of the skull. Between the dura mater and arachnoid mater is the sub-dural space. This layer contains the bridging veins that can tear in the elderly when the brain shrinks, and produces chronic collections of blood called chronic subdural haemorrhages.

The extradural space lies between the skull and the extradural layer. This contains an artery just around the temple of your forehead that can burst with skull fractures and trauma and bleed causing an extra-dural haemorrhage.

Cerebrospinal Fluid and the Ventricular System

Cerebrospinal fluid (CSF) is a clear fluid that circulates within the brain through a system of cavities and canals called the ventricular system. The brain has around 150 mls, or just under half a lemonade can full of CSF at any one time. However, 500 mls of CSF are produced daily and the fluid circulates and is reabsorbed. There are four ventricles or cavities deep within the brain – two larger lateral ventricles and two smaller ones. The ventricles are connected via small channels and the CSF goes into the subarachnoid space and into a canal in the spinal cord. After some further wandering it is absorbed and passes into the venous system.

Figure Six: The Ventricular System

CSF and the ventricular system protects the brain in a number of ways. Firstly, it can assist in clearing waste from the brain. Secondly, it can act as a sort of shock absorber. Thirdly, it also functions to support the brain within the closed space of the skull so that the brain almost floats within the fluid.

The protective functions of the CSF system only become problematic if, for a variety of reasons, a blockage develops. This is discussed later in the book in the section describing hydrocephalus.

The Achilles Heel of the Brain

The protective system of the brain can also become its worst enemy at times of brain injury. Because the brain lies within a sealed skull, which is in essence like a closed box, problems develop if bleeding occurs within the brain or if the brain itself swells in response to injury. The brain consists of a mixture of brain tissue, blood and cerebrospinal fluid. Any increase in the amount of one of these automatically means a reduction in the amount of space available to the other two. Therefore, if a bleed occurs within the brain, the increased volume of blood leads to increased pressure and this in turn puts pressure on the surrounding brain tissue and CSF volume leading to further brain damage. Similarly, if the brain swells as a result of an infection or in response to damage, this increases the pressure within the skull and runs the risk of reducing blood flow producing further damage. Likewise, blockages within the CSF system lead to a greater volume of CSF and increased pressure and damage to the brain causing reduced blood flow, again, producing further damage. The delicate balance that therefore exists within the brain can be altered as a result of an injury and brain damage begets further brain damage.

Figure Seven: The delicate balance within the brain: (Left) A normal balance (Right) Effect of bleeding on the brain with increased intracerebral pressure and increased volume of blood.

Chapter Two

What is a Brain Injury?

An acquired brain injury (ABI) is the name given to any damage to the brain that occurs after birth. The damage may be localised to one part of the brain or it may be generalised and affect the whole brain.

When the damage occurs as a result of direct trauma to the brain, such as in a car crash, it is called a traumatic brain injury. ABI may also be the result of a bleed within the brain, lack of oxygen to the brain, an infection or inflammation of the brain, or due to a cancer or an autoimmune process.

Traumatic Brain Injury

Traumatic brain injury occurs as the result of an external force impacting upon the brain, for example, as a result of a fall or assault. That force may be penetrating meaning something actually goes through the skull and directly damages the brain, or be non-penetrating meaning the tough protective skull isn’t breached.

Penetrating brain injuries may occur as a result of gunshot wounds to the head or, more commonly in the UK, when an object such as part of a car goes through the skull at speed. In addition to damaging the brain at the point of impact, penetrating brain injuries also introduce potential sources of infection into the brain and as such are very serious. They are associated with far higher rates of subsequent epilepsy than non-penetrating head injuries.

Non-penetrating injuries are just as serious and can occur either due to an object hitting the head, such as occurs in an assault, or due to the rapid acceleration and deceleration forces that occur in a car crash. The brain, as already mentioned, has the consistency of cold porridge and almost floats within the skull thanks to the small layer of cerebrospinal fluid. It is therefore particularly sensitive to sudden forces like when a car hits an object. When this happens, the brain crashes against the inner skull and as it rebounds, the opposite end of the brain hits the inner skull on the other side of the head. This causes what’s called a coup and countercoup injury. In addition, rotational forces that cause the brain to twist within the skull at the time of impact are also important. Normally people are facing forward when they are involved in car crashes, so it is the frontal lobe in the front of the brain that gets the immediate impact followed by the back of the brain getting the impact as the brain rebounds.

Figure Eight: Coup and Countercoup Injury.

The impact of the brain against the skull can cause some localised bruising and damage to the surface of the brain called a contusion. Unfortunately, the skull that covers the front part of the brain, especially just behind the eyes, has lots of bony bumps which can grate against and damage the brain underneath after trauma. As we now know, that part of the brain has a particular role in behaviour and in controlling social behaviour and delaying instant gratification. Damage therefore results in significant behavioural issues as we’ll see in the chapter on organic personality disorder. The impact of the brain against the skull may also tug on and shear some of the blood vessels in the brain and cause a bleed.