On the other hand, not all touch is interpreted positively, even when so intended by the nurse (Davidhizar & Newman 1997). Because of these potential positive or negative effects, nurses need both to understand touch and to value the ability to use it therapeutically. Touch, in a nurs-ing context, may be either instrumental (which includes all functional touch necessary to carry out physical procedures such as wound dressing or taking a pulse) or expressive (used to convey feelings). Nurses are unusual in that they are ‘licensed touchers’ of relative strangers. This legitimized transgression of the normal social code requires that nurses are sensitive to the reactions of patients.

Cultural uses of touch vary from country to country. Murray & Huelskoetter (1991) noted that cultures such as Italian, Spanish, Jewish, Latin American, Arabian and some South American countries typically have relationships that are more tactile. Watson (1980) identified England, Canada and Germany as countries where touch is more taboo. These cultural differences in social codes heighten further the need for sensitivity when judging if touch is appropriate (see Box 7.1). Whitcher & Fisher (1979) found that the use of therapeutic (expressive) touch by nurses preoperatively produced a positive response to surgery among female patients, but not male patients. There is some evidence that males may perceive touch differently to females in relation to aspects of status or dominance (Henley 1977).

Proxemics refers to the spatial position of people in relation to others, such as respective height, distance and interpersonal space. Hall (1966) originally identified four different interactive zones for face-to-face contact and considered anything less than 4 feet as intrusive of interpersonal space in most relationships other than intimate ones. The four zones are used differently according to the topic of conversation and the relationships of the participants. Patients in hospital settings may not perceive that they have any real personal space. French (1983) suggested that an area of 2 feet around a patient’s bed and locker could be viewed as personal space. One’s spatial orientation and respective height to the other person are also significant and should be considered when engaging with others.

Posture conveys information about attitudes, emotions and status. For example, Harrigan et al (2004) suggested that depressed and anxious patients can be identified purely by non-verbal communication. A person who is depressed is more likely to be looking down and avoiding eye contact, with a down-turned mouth and an absence of hand movements. An anxious person may use more self-stroking with twitching and tremor in hands, less eye contact and fewer smiles. Of course, the nurse’s posture carries just as many social messages. The ideal attending posture to convey that one is listening has been variously described in the literature (Egan 1998).

This includes all body movements and mannerisms. Gestures are commonly used to send various intentional messages, particularly for emphasis or to represent shapes, size or movement, or may be less consciously self-directed and sometimes distracting to others. Head and shoulder movements are used to convey interest, level of agreement, defiance, submission or ignorance.

Facial expressions provide a running commentary on emotional states according to Argyle (1996) and Ekman & Friesen (1987) identified six standard emotions that are universally recognizable across all cultures by consistent movement of combinations of facial muscles, namely happiness, surprise, anger, fear, disgust and sadness.

Eye contact is a universal requirement for engagement and interaction. In Western society listeners look at speakers about twice as much as speakers look at listeners (Argyle 1996), although there are cultural variations to this. When people are dominant or aggressive they tend to look more when they are speaking. The absence of eye contact may indicate embarrassment, disinterest or deception.

Our self-presentation makes statements about our social status, occupation, sexuality and personality. Some aspects of appearance can be easily manipulated, such as our dress and hairstyle, but other features are beyond our control, such as height. Both types of presentation communicate messages about who we are. Nurses have often discussed the merits and disadvantages of wearing a uniform. Uniforms and other forms of regalia make nurses easily identifiable to others and provide additional information about seniority and qualifications. In some contexts, uniforms may be seen to present a barrier to establishing therapeutic relationships by reinforcing the power of the professional in the relationship. Try Activity 7.1.

Paralinguistics includes those phenomena that appear alongside language, such as accent, tone, volume, pitch, emphasis and speed. It is these refinements of the lexical content that provide meaning to spoken communication. It is possible to use the same actual words but with contrasting paralanguage and convey an entirely different meaning. After reading Case history 7.2, which concerns communication with an unconscious patient, try Activity 7.2.

The nature and organization of the physical environment in which any communication takes place will have significant impact on the interaction. In Case history 7.2, the patient is completely at the mercy and compassion of her nurses. Fortunately, Deana is blessed by having nurses who are sensitive to her need for sensory stimulation and companionship, even though they are not getting an obvious response from Deana. She may have different nurses who are less aware of the importance of communication, both through touch and through sound, to help her remain orientated, even though she is unable to communicate her level of consciousness. Less skilful or less insightful nurses might treat her as an object that needs specific tasks to be done, so Deana might be treated as a work object rather than a human being, and simply a bed number that needs attention.

Another clear example is the difference between visiting patients in their homes and nursing them in a hospital ward. Being a visitor in a patient’s or client’s home significantly alters the power relationship and thus the locus of control. The nurse has less control over the environment in the patient’s home setting and is a guest. Hospital buildings are unusual settings for most patients and provide consistent reminders that the health care professionals are in control of the environment to a large extent. Wilkinson, 1992 and Wilkinson, 1999 recognized that nursing environments were often not conducive to open communication, even if the nurses were highly skilled in it. Making the most strategic use of facilities available according to the nature and purpose of the exchange is an important aspect of nursing communication.

All of the channels of non-verbal communication described above are extremely important and may constitute up to 90% of the communication taking place. They do of course occur in various combinations with each other, not separately as above. The various functions of non-verbal communication are summarized in Box 7.2.

So how are humans able to develop all these subtleties in their everyday speech and language use? Why is it important to understand the physiological processes? With these questions in mind, complete Activity 7.3 and Activity 7.4.

Air is supplied from the lungs by carefully controlling breathing to allow regulated volumes of air to pass through the upper airway passages. The muscles involved are those of normal breathing (i.e. the diaphragm and the intercostal muscles between the ribs). At the top end of the trachea is the larynx (or voice box), which is a hollow structure made mostly from tough cartilage and lined with mucous membrane (Figure 7.2). The narrowest point of the air passage inside the larynx is called the glottis, and across this point are stretched the vocal cords. These vibrate in the air passing across them creating sound. Variations in the pitch of this sound are achieved by changing the tension on the cords; volume is changed by varying the force of air released from the lung across the vocal cords. Some muscles of the larynx attach to the corniculate cartilages (which are mounted on the aretinoid cartilages).

The corniculate and aretinoid cartilages are involved with opening and closing the glottis, and the production of sound. The muscles attached to these cartilages adjust the tension on the cords, changing the vibration frequency, and thus the sound produced. These sounds are not yet words. To achieve this we need the help of the tongue, jaw, lips and mouth. Precise muscle movements of the tongue, throat and lips allow for the shaping of the laryngeal sounds into recognizable words. Figure 7.3 shows in diagrammatic form the various anatomical features involved in vocalizing sounds (Seeley et al 2006).

Some people who have suffered from a traumatic injury to the neck or have developed cancer of the larynx, have had their larynx removed surgically. This is known as laryngectomy (‘ectomy’ means removal). Without the two cartilages open-ing and closing the glottis, air cannot vibrate as it passes up the throat, leaving the patient without a voice. This represents a major change in ‘body image’ and a huge challenge for the patient, who must learn to speak through other means. Some patients were given a speaking tube that fitted through the neck and allowed air to pass through, thus mimicking the larynx. With modern technology, patients can learn to produce artificial speech from a synthesizer (Blows 2005).

In the part of the brain called the motor cortex, there is an area, known as Broca’s area, which has specific control over the muscles of speech. However, the complexity of speech requires several different groups of muscles to work together, and so neuromuscular control of speech is far more sophisticated than that for other muscles. The brain shows lateralization for speech; that is, only one side of the brain carries out the function of controlling speech muscles. More than 95% of right-handed people have their Broca’s area on the left side of the brain for speech, whereas in left-handed people the figure is about 70%. So, for the majority of people, speech is a left-sided brain function.

Broca’s area is a region in the frontal lobe of the left cerebral cortex located below the primary motor cortex (see Figure 7.4). It appears to be a major site for the coordination of the muscles of speech (i.e. muscles of the tongue, lips and jaws). There may be muscle motor memory stored here that assigns specific muscle movements that will be required for the pronunciation of words. Creating speech is so sophisticated that it requires several related areas in the brain to work together, so near to Broca’s area are deeper structures in the brain tissues that are also involved. These include an area known as the caudate nucleus (part of the basal ganglia), parts of the insular (a region of cortex hidden behind the temporal lobe), the peri-aqueductal grey matter (within the brainstem) and the cerebellum. Studies of people who are mute, or people who cannot make sounds, found that they have damage or lesions in one or other of these areas. It has not yet been possible to determine the exact relationship of these structures or their specific contribution to making speech.

Being able to make and shape sounds into speech is only part of the process. Another important aspect is how we create words and sentences and language that is grammatically correct. Learning to shape sounds takes practice as well as the ability to recognize sounds as having specific meanings. We achieve this through another part of the brain, thought to be Wernicke’s area. This seems to be the major site for recognizing and understanding words and producing meaningful speech. Wernicke’s area is located in the posterior part of the auditory association cortex within the left tem-poral lobe (Figure 7.4). The auditory association area lies next to the main auditory cortex, the area that deals with hearing.

Language is either spoken or written, and the pathways connecting the various areas of the brain are different for spoken words than for written words. Spoken language involves hearing words (i.e. input to the auditory cortex); vocal responses involve Wernicke’s area, followed by Broca’s area and the main motor cortex to operate the muscles of speech. Written language first involves seeing words written down (i.e. input to the visual cortex); verbalizing those words again involves Wernicke’s area, linked to Broca’s area and the main motor cortex.

As indicated above, aphasia is an impairment of language affecting the production or comprehension of speech and the ability to read or write. Aphasia is caused by injury to the brain, most commonly from a stroke (see Case history 7.3) and particularly in older adults. The aphasia can be so severe as to make communication with the patient almost impossible, or it can be very mild. Expressive aphasics are able to understand what you say, receptive aphasics are not. Some victims may have a bit of both kinds of the impediment. For expressive aphasics, trying to speak is like having a word ‘on the tip of your tongue’ and not being able to call it forth. When communicating with individuals who have aphasia, it is important to be patient and allow plenty of time to communicate and allow the aphasic to try to complete their thoughts, to struggle with words. Avoid being too quick to guess what the person is trying to express. Ask the person how best to communicate and what techniques or devices can be used to aid communication. A pictogram grid can be used as these are useful to ‘fill in’ answers to requests such as ‘I need’ or ‘I want’. The person merely points to the appropriate picture.

The whole hearing system is sensitive to vibrations. The source of the sound causes vibrations to occur in the air, and these move outwards like ripples on a pond. Such vibrations are funnelled down the auditory canal to the tympanic membrane, which then also vibrates. Tympanic membrane vibrations are transmitted through movements of the ossicles to the oval window, resulting in vibrations occurring in the membrane covering the oval window (Figure 7.8). The purpose of the ossicles is both to amplify the vibrations and to concentrate them onto the oval window. This amplification/concentration effect results in vibrations of the oval window being about 22 times greater than the vibrations of the tympanic membrane. The oval window vibrations cause ripple-like waves in the perilymph of the vestibule. These waves pass down the cochlear in the upper chamber, the scala vestibuli, and are transmitted across the upper membrane to the endolymph within the cochlear duct below. This in turn vibrates the basilar membrane and the organ of Corti on that membrane.

Different sound frequencies cause vibrations in different parts of the organ of Corti; this is why humans are able to appreciate different sounds. The brain recognizes which hair cells on the organ of Corti are affected by vibrations and which are not. It is then possible for the brain to interpret this as specific sounds. Part of this achievement is due to the differing abilities of the basilar membrane to vibrate throughout its length. At the oval window end, the basilar membrane is stiff and narrow (despite the cochlear being widest at this point) and it vibrates here at a frequency of about 20 000 Hz. At the helicotrema, the basilar membrane is at its widest (although the cochlear is narrow) and more flexible. Here it vibrates at about 20 Hz frequency of sound. Between these two points the basilar membrane varies gradually in width, stiffness and flexibility, allowing for a wide spectrum of sound appreciation.

At rest, the stereocilia on the hair cells are upright and potassium channels in these structures are partly open, allowing small quantities of potassium to enter the hair cells. As a result, the hair cells release low levels of neurotransmitter into the synapse between the hair cell and the neuron below. This neuron then sends low-frequency impulses (also called action potentials) along the nerve to the brain. Endolymph and tectorial membrane vibrations created by incoming sounds cause the stereocilia of the hair cells to bend one way or the other. If they bend towards the longer stereocilia a greater increase in potassium (and calcium) into the hair cell occurs. This causes more neurotransmitter to be released and therefore greater intensity of action potentials sent to the brain. If the stereocilia are bent towards the shorter ones, the potassium input to the hair cells is cut off and no neurotransmitter is released. This results in no action potentials being sent to the brain (Shier et al 2004).

Impulses from the organ of Corti pass along three orders of neurons (Figure 7.9), the first being those of the cochlear nerve. Hair cells are connected to nerve endings that are terminations of the cochlear nerve. This nerve is one branch of the vestibulocochlear nerve, the eighth cranial nerve that passes to the cochlear nuclei of the brainstem. From here, second-order neurons partly cross to the opposite side (known as decussation) to another medullary centre, the superior olivary nucleus. Others pass to the superior olivary nucleus on the same side as their origin. From these nuclei, ascending neurons course through the pons and midbrain and terminate in the medial geniculate nucleus of the thalamus. The third-order pathway is to the conscious brain, the auditory cortex of the temporal lobe, which is part of the cerebral cortex.

The eye is mounted inside a bony socket called the orbit. Each eye is moved around in the orbit by six muscles controlled by three cranial nerves from the brainstem (Blows 2001). The internal structure divides the eye into two main compartments: the anterior and posterior cavities (Figure 7.10). These are fluid-filled compartments; the anterior cavity contains aqueous (water-like) humour, the posterior cavity contains vitreous (jelly-like) humour. Both fluids are crystal clear to allow for the passage of light.

The wall of the eye is composed of three layers: the outer sclera (the white of the eye), the middle choroid coat (a vascular layer) and the inner retina (the light-sensitive layer). At the front of the eye, the sclera becomes a round clear patch (the cornea), which bulges forwards slightly due to the pressure of the aqueous humour of the anterior cavity. Also towards the front, the choroid layer becomes the ciliary body, the base to which suspensory ligaments attach for holding the lens. Suspensory ligaments play a vital role in changing the shape of the lens for the purpose of accommodation, which is the ability to focus on objects at different distances. Accommodation is automatic, governed by the brainstem via the third cranial nerve. Problems with accommodation are not uncommon. Myopia is near-sightedness (i.e. the ability to see close up but distance vision is blurred). The opposite is hypermetropia (hyperopia; i.e. far-sightedness, where close objects are seen as blurred but distance vision is clear). Presbyopia is a natural age-related change in the lens resulting in a gradual loss of normal accommodation. Like all ageing processes it is not preventable. The ‘near-point’ is the closest an object can get to the eye and remain in focus. In presbyopia, the near-point extends gradually further away, from a normal 23 cm to sometimes an arm’s length or more. Fortunately, accommodation errors can be corrected with suitable glasses (Seeley et al 2006).

Extending forwards from the ciliary body is the iris, which divides the anterior cavity into an anterior chamber and a posterior chamber. The aqueous humour that fills both is produced from the ciliary body and flows forwards through the pupil, the opening at the centre of the iris, and is reabsorbed by a canal (the canal of Schlemm) in the anterior chamber. In this way, the aqueous humour is constantly being renewed, being derived from blood plasma and returning to blood plasma. The iris can close the pupil (in bright light) or open the pupil (in dull light) in order to regulate the amount of light falling on the retina. Like accommodation, this action is automatic, being controlled by the third cranial nerve.

The retina is unique in one respect: it is the only part of the nervous system that is visible from the outside world. It is formed during embryological life as a forward growth from the brain, and can be viewed using an ophthalmoscope. It is the light-sensitive layer that converts light into nerve impulses. These travel to the brain via the optic nerve (the second cranial nerve).

Light passes through the cornea and the pupil, and is concentrated and focused on the retina by the lens. The retina has two main cell types: rods and cones (Figure 7.11).

The rods are specialized retinal cells for responding to black and white and to night (low-light) conditions; cones are similar cells for responding to colour and to day (bright-light) conditions. Rods have a high sensitivity to light (this is needed in low-light situations) and there are many of them (100 000 000, or 10⁸, per retina). Compare this to the cones, which have low sensitivity to light (suitable for bright light) and are fewer in number (3 000 000, or 10⁶, per retina); cones do not respond at all well in low-light situations. There are three types of cones (red, green and blue), providing a full spectral colour range; they are more concentrated at the fovea (Figure 7.11). Both rods and cones carry out phototransduction, which is the conversion of light energy to nerve impulses. This involves complex chemical changes starting with a light-sensitive pigment called rhodopsin (or visual purple) which is partly produced from vitamin A.

Rods and cones are attached to a second layer of cells (the bipolar cells), which in turn are connected to ganglion cells leading to the optic nerve. The surprising aspect is the manner in which these layers occur in the retina. The rods and cones are the innermost layer (towards the choroid), and the ganglion cells are the outermost layer (nearer to the vitreous humour) (Figure 7.11). This means that light striking the retina must first pass the ganglion and bipolar cells before reaching the rods and cones. Convergence (i.e. several rods linked to a single bipolar cell) occurs across the retina; this also applies to cones but to a lesser extent.

Another surprise is that light deactivates the rods and cones; that is, light switches them ‘off’ not ‘on’. In the dark, both rods and cones produce a neurotransmitter at the synapses between them and the bipolar cells. This chemical increases activity in the bipolar cells, which in turn affects the activity in ganglion cells. Some bipolar–ganglionic synapses are excitatory, increasing ganglionic activity; others are inhibitory, decreasing activity. In the light, the rods and cones produce far less neurotransmitter and therefore the bipolar and ganglion cells are less affected by them. In this way, variations in light or dark on the retina are communicated to the ganglion cells, and thus to the optic nerve (Shier et al 2004).

Impulses generated by the retina travel along the optic nerve and arrive at the optic chiasma (Figure 7.12). Here the two optic nerves join, allowing the lateral half of each retinal output to remain on the same side, while the medial halves (nearest the nose) cross to the opposite side (known as decussation). From here backwards the visual pathways (called optic tracts) are contained within the brain. The left optic tract carries impulses from the left lateral and right medial retinas; the right optic tract carries impulses from the right lateral and left medial retinas. These pass to part of the thalamus called the lateral geniculate nucleus, and from there they pass via the optic radiations to the visual cortex in the occipital lobe of the cerebrum. The impulses arrive upside down and split between the two sides, which would create a very strange view of the world.