Causes of Tinnitus

How we hear

Our hearing system can be divided into three main parts: the external (E), middle (M) and inner (I) ears. These link to the brain via the auditory nerve.
The external ear (E) consists of the pinna (the part visible on the outside of the head), ear canal and ear drum. This section is also referred to as the outer ear and it acts as a sound funnel. The outer ear canal wall produces cerumen, or wax, which moves towards the outside. Wax protects the ear, removing foreign bodies and germs from the ear canal and away from the ear drum.
The middle ear (M) is an air filled space containing a chain of 3 tiny bones called the ossicular chain. The 3 bones (ossicles) are called the malleus, incus and stapes. The malleus is the first bone in the chain. It is attached to the back of the ear drum on one end and to the incus on the other. The incus attaches to the stapes, which rests in the oval window of the inner ear. The middle ear is connected to the back of the nose and throat via the Eustachian tube. This tube maintains equal air pressure between the middle ear and the air around us. The eardrum and the ossicular chain vibrate in response to sound waves entering the ear.
The inner ear (I) consists of the cochlea, a small snail-shell shaped organ set within the bone of the skull. The cochlea contains fluid and tiny hair cells which vibrate in response to the movements from the middle ear, and stimulate thousands of nerve endings in the auditory nerve. The auditory nerve travels through the skull, carrying sound messages to the brain, which decides what the sound is. The inner ear also contains the semi-circular canals, which contribute to one’s sense of balance.
Messages from the ear travel up the auditory nerve pathways to the brain, where sounds are perceived and interpreted. Along the way, other nerve pathways communicate with the auditory pathway to help us associate sounds with memories and emotions.

Hearing loss

Hearing requires sound to travel through the outer and middle parts of the ear to the nerve endings in the inner ear. When there is a breakdown in the passage of the sound to the inner ear it is called a conductive hearing loss. When the disorder is in the inner ear or the auditory nerve it is termed a sensorineural hearing loss. If either the outer or middle ear and inner ear are affected, it is termed a mixed hearing loss.
Conductive hearing loss: Many things can cause a conductive hearing loss, including wax blockage in the ear canal, a hole in the ear drum, infection in the middle ear, or disease of, or damage to, the tiny bones of the middle ear. Conductive hearing loss can also occur with other nose or throat problems.
Sensorineural hearing loss: The inner ear or auditory nerve can be damaged by loud noise exposure, viral and bacterial infections, some diseases, some prescribed medications, head injury, blood vessel problems and the aging process. These conditions can lead to sensorineural hearing loss.
Three significant symptoms of hearing loss include:
Loss of the ability to hear soft sounds, e.g. quiet voices, the bell on the microwave. This is particularly noticeable when there are other sounds present
Loss of sound clarity, “I can hear people talking but I can’t make out the words”
Increased sensitivity to loud sounds, some people find loud sounds intolerable.

Tinnitus

Tinnitus can be defined as an individual’s perception of a sound when there is no actual external sound present. Tinnitus perception varies greatly between individuals, but it’s often described as a ringing, buzzing. hissing, roaring, clicking, or pulsing sound. It can be perceived in one ear, both ears and sometimes alternate between the ears. Some people may notice their tinnitus many times a day whereas others notice it seldom. People’s perception, awareness and reaction to tinnitus vary greatly within the population.
Individuals with tinnitus tend to be most aware of it in quiet environments, such as when they go to bed or get up in the morning, as there is less external sound masking the internal noise of the tinnitus.
Tinnitus is not a disease, but rather a symptom of something wrong with or affecting the auditory system. It is a complex condition that can involve many structures in the head neck ear and brain. We do know that hearing loss is often associated with tinnitus (but not always).

Hearing loss and tinnitus

In many cases, there is a strong correlation between hearing loss and tinnitus. It is particularly common in people who have been exposed to high levels of noise in their jobs or recreational activities. In particular, people working in noisy industries such as manufacturing, manual labour, farming and the music industry can have noise damage to the inner ear, leading to noise induced hearing loss and tinnitus.
Approximately 20% of the Australian population experience tinnitus and 90% of those have hearing loss. So it is important that if you have tinnitus, you have your hearing assessed by an audiologist and be examined by a GP or Ear Nose and Throat Specialist (ENT). The information they provide will ensure that the appropriate treatment or management strategy can be recommended.
If tinnitus is a result of a conductive hearing loss (problems in the outer or middle ear) it is possible that with medical intervention it can be treated, but if secondary to a sensorineural loss (inner ear or nerve damage) it is not usually improved through medicine or surgery.
For tinnitus which cannot medically or surgically be treated there are a wide range of management options which may include using hearing instruments, sound therapy or noise generators, and counselling.

Noise and tinnitus

Exposure to loud noise is one of the most common causes of tinnitus and hearing loss. Excessive loud noise exposure can damage the auditory system in a slow and unnoticeable way over a long period of time, or suddenly as a result of exposure to extreme impulse noise. Noise can also make existing tinnitus louder and cause hearing to get worse.
Sometimes the auditory system can partly or completely recover from noise-related tinnitus or hearing loss. However, repeated exposure to high level sounds will eventually result in permanent damage to the inner ear, leading to permanent hearing loss.
Sound is transmitted by vibrations through the outer and middle ear to the inner ear. The inner ear, or cochlea, is made up of three chambers. The middle chamber is lined with tiny hair cells and filled with fluid. The hair cells of the inner ear are stimulated as the fluid is moved by the vibrations sent from the middle ear. Each stimulated hair cell sends a message to the brain.

Excessive exposure to noise damages these inner ear hair cells. The damage is permanent and the hair cells cannot be replaced and do not regrow. Hearing sensitivity is therefore affected and tinnitus can begin as a result of the damage. The commencement of tinnitus can be gradual or sudden and in some cases the tinnitus will start before any loss of hearing is noticed. Some people can find the tinnitus more disturbing than any hearing loss itself .

The degree of damage caused by noise exposure is determined by the intensity level of noise and the length of exposure time. Sound intensity level is measured in decibels (dB). This is not a linear scale so the danger of noise can be easily misinterpreted. For example an increase in intensity level from, say, 40 dB to 43 dB actually represents a doubling of the physical intensity. However, when listening to sound we actually need a change of about 10dB before we perceive the sound to be twice as loud. Generally, 85dB is the maximum allowable level at which you should be exposed to noise for an eight hour period, as illustrated by the diagram on the previous page (as a rough guide 80-85dB is about the noise level on a busy road). If you are exposed to sound louder than this, then the time you are subjected to the noise will need to be reduced to avoid hearing damage. The cumulative effect of ALL noise exposure results in damage to the auditory system.

Everyday indicators that may suggest damage to the auditory system include:

  • Dull hearing – feeling ‘deaf’ after noise exposure or at the end of the day
  • Tinnitus or noises in the head after exposure to loud noise
  • Muffled or distorted hearing
  • Thinking that people are mumbling
  • Loud sounds feel painful

Also if you notice:

  • The car radio needs to be turned down in the morning – i.e. it was set louder when you last drove the car after work
  • As general rule, if you need to shout or use a raised voice in order to speak to someone at an arm’s length, the noise in that area is possibly dangerous to the ear

Remember, noise does not need to be unpleasant to cause damage to the auditory system.

What Action Can You Take?

There are many ways to avoid hearing loss and tinnitus caused by too much loud noise. Firstly, eliminating the noise source should be considered. Removing or reducing the level of the noise at its source is the preferred and best option; alternatively, increase the distance between the noise source and the listener. This may be a simple as moving noisy equipment away from your work area, e.g. moving air compressors into an adjacent room, turning down the level of your home stereo or ipod. Always consider the noise levels when purchasing new equipment.

Purchasing quieter equipment can save workers’ hearing in the long term. Noise barriers or other controls can also be considered to alter the noise pathway.

Sometimes, however, the above actions are not possible. In these cases implementing job rotation can reduce the period of exposure in the workplace. Job rotation, or simply having a break, is an excellent way of reducing the amount of time spent in noisy areas. This can also reduce workers’ fatigue levels.

You should wear personal hearing protection whenever you work around intense noise. There are many ear muffs and ear plugs available to protect ears from harmful noise. When selecting hearing protection consider its comfort, correct fit, the amount of blockage required to protect your ears and communication issues.

There are customised and specialised  plugs available for musicians, motor bike riders, night-shift workers and industrial workers. An Audiologist will be able to help you choose the correct style and fit for your needs.

Loudness Recruitment, Hyperacusis and Phonophobia

Most people dislike continuous loud noise, but some people are especially sensitive to ordinary levels of noise. This sensitivity, or reduced tolerance, can take different forms and be caused by different things.

Loudness Recruitment

Loudness Recruitment occurs in some ears that have high frequency hearing loss due to disease or damage to the cochlea (the inner ear). Loudness Recruitment refers to the rapid growth of loudness of certain sounds that are around the same pitch of a person’s hearing loss. That is, sounds can be perceived as soft and then with only small increases in intensity they can be perceived as too loud. As people with Recruitment also have hearing loss this means that they may not hear someone speak in a normal voice, but find a raised voice very loud.

Hyperacusis

For people with hyperacusis, all except the quietest of sounds are uncomfortably loud. Sudden loud sounds can seem explosively loud and cause physical discomfort for some people.
Most hyperacusis is the result of exposure to extreme loud noise, either continuously over a period of time or once only. The person with hyperacusis may find even low intensity sounds (such as the hum of a computer monitor or of a refrigerator) uncomfortably loud. For some people with hyperacusis, the sensitivity is made worse for up to a day following exposure to a loud sound.
Hyperacusis affects some patients with other health problems, such as Lyme’s Disease, chronic fatigue syndrome, Bell’s palsy, head injury and epilepsy. It is also a characteristic of autism; some autistic children find all sounds too loud.
A person with hyperacusis may have normal hearing or some degree of hearing loss and typically has tinnitus, too.

Phonophobia

Another form of sound sensitivity is phonophobia – fear that certain sounds or types of sounds will affect the hearing or make tinnitus worse, leading the person to avoid those sounds as much as possible. Sometimes phonophobia develops as a result of hyperacusis. The person becomes afraid of exposure to sounds which seem loud to them and which they think will damage their hearing.

Sound sensitivity and tinnitus

Tinnitus and hyperacusis occur together quite frequently because the same conditions of the auditory system and/or nervous system can underlie both problems, e.g. exposure to excessive noise, anxiety. Tinnitus DOES NOT cause hyperacusis, however, nor does hyperacusis cause tinnitus.

Management of sound sensitivity

The management of sound sensitivity aims to return the person to a normal sound environment without experiencing discomfort.

There are six components to the management of sound sensitivity:

  1. Shielding from sounds that actually are loud by using effective individual hearing protection when in a noisy workplace or using noisy equipment (such as power tools, electrified musical instruments, firearms)
  2. Discouragement of excessive hearing protection: the person must be ‘weaned off’ the use of hearing protection when the noise is not actually hazardous. If the person is experiencing severe discomfort in some moderately-noisy situations, this may be done by using specially constructed ‘electronic’ earplugs or sound processors which reduce the intensity of very loud sounds, only
  3. Information and counselling about the causes of hyperacusis to provide reassurance and allay anxiety
  4. Sound enrichment: the person with hyperacusis should avoid silence and, at all times, have low level, natural sound present in their environment. Useful aids include CDs or other devices which provide digitally-produced sounds of nature such as running water, bird calls, or the sound of rain falling
  5. The use of wearable noise generators (or the Neuromonics device): these help the person become desensitised to noise
  6. Progressive desensitisation: a person with severe phonophobia may need additional help to overcome their fear of particular sounds. This entails counselling to help them adjust to sounds which are progressively more like the sounds which trigger the strong response, e.g. sirens or telephone bell

Tinnitus Retraining Therapy and the Neuromonics acoustic desensitisation protocol have both shown promise for managing sound sensitivity.

About half of all people with tinnitus report that it disturbs their sleep. This may mean that the tinnitus makes it hard for them to drop off to sleep, prevents them from returning to sleep when they wake in the night, or wakes them before they are ready to get up.

Normal sleep

Different people need different amounts of sleep. Some people need at least eight hours, others can get by on only three or four. As you grow older, you are likely to experience less deep sleep, more light sleep, and more awakenings during the night.
Lack of physical activity may contribute to poor sleep patterns, so increasing physical activity can lead to improvement.
Everyone has a ‘natural sleepiness cycle’. Sleepiness tends to increase every 60 to 90 minutes or so. As you find yourself getting sleepy, you may decide “I’ll just finish this . . .” but by the
time you finish your task, the sleepiness has passed – you’ve got your ‘second wind’. If you go to bed during the wave of sleepiness you’ll fall asleep more quickly.
Lying in bed just resting is also relaxing – you don’t have to be asleep. Lying in bed peacefully is much more restorative than lying in bed worrying.
Sleep can be disturbed by sounds, physical discomfort, travel across time-zones, or worry.
Everyone has a bad night now and then but generally recovers with a night of good sleep.

States and stages of sleep on a typical night

Normally, sleep begins with Stage 1 of NREM (non-rapid eye movement) sleep, which feels almost like meditating. A few minutes later, in Stage 2, the awareness of place is gone. Sleep becomes deeper and more restful during Stages 3 and 4. During these four NREM stages, the body slows down. Heart and breathing rates and body temperature all slowly decrease. Then sleep drifts back through Stages 3 and 4. This total NREM period is normally 80-100 minutes. Suddenly, REM (rapid eye movement), a different kind of sleep, begins. The eyes move back and forth in this stage. The heart and breathing rates increase and become erratic. There are vivid dreams during REM sleep
This NREM/REM cycle recurs approximately every 90 minutes throughout the night. It is also normal to wake briefly, several times during the night.

The effects of tinnitus on sleep

Tinnitus can affect your sleep in different ways.
First, the incessant noise of the tinnitus can be an annoying distraction when you are seeking peace and quiet, thus preventing you from dropping off to sleep.
Second, worrying about the tinnitus, listening to it actively and wondering about it may also increase your physical and mental tension and make it hard to relax enough for sleep to overcome you. Tinnitus typically sounds louder when there are fewer external sounds present – the night and early morning are quiet so your tinnitus may seem to be amplified.
Some people also find their tinnitus very noticeable in the morning, perhaps because the slight ear blockage present on awakening dulls their hearing and increases their attention to internal sounds.

Managing sleep difficulties

Treatment for sleep difficulties associated with tinnitus consists of:

Sleep Education: learning about normal sleep patterns and the normal sleep/wake cycle.

Sleep Hygiene: only using your bed for sleeping – avoid reading, watching TV, using electronic devices or eating in bed.

Establish an Optimal Sleep Pattern: go to bed at around the same time each night but if you do not fall asleep within about 30 minutes of turning out the light, get up and do something else until the next wave of sleepiness arrives.

Sleep Restriction: avoid daytime naps and going to bed before 10.00pm. Avoid trying to ‘make up’ for lost sleep by sleeping in or going to bed very early.

Relaxation: stress, anxiety and worry related to the tinnitus and/or to other events can disturb your sleep. There are specific and effective techniques that can reduce or eliminate anxiety and body tension. As a result, your mind is able to stop ‘racing’, your muscles can relax, and you can drift into restful sleep. Enrol in a relaxation course near home or try guided relaxation practice using a recording - from music stores, bookstores or over the Internet.

Rehearsal/planning: list activities for the next day to ‘put them out of your mind’, avoid eating spicy foods or performing any energetic exercise in the hour or two before you go to bed, wind down with a relaxing activity, e.g. have a warm bath.

Use of External Sounds: it is important to avoid silence so that your ear has something ‘real’ to listen to. This will help to distract you from the tinnitus. Opening the window or turning on a fan provides subtle sound. Bedside sound generators of various kinds, including smartphone applications, can deliver non-meaningful sounds via a standard speaker, an earphone or ear-bud, or a special speaker under the pillow.

More Information
“Sleep Better Without Drugs” Dr David Morawetz  
Sleep Resources   
Apple Itunes/App Store
Google Play Store

Flying or diving may impact your tinnitus. Understanding what happens to your ears when you fly or dive and knowing how to minimise the risks will help you to enjoy these activities.
The middle ear is normally filled with air that is the same pressure as the surrounding air. The air in the middle ear is absorbed by the body and when we swallow or yawn the Eustachian tube (connecting the middle ear with the back of the nose) opens and lets air pass into the middle ear, equalising the pressure.
If you are worried about your Eustachian tube function please contact your audiologist and they can easily test your Eustachian tube function through tympanometry.

How pressure affects your ears when you fly

If there is going to be a problem with equalising pressure when flying, it usually occurs when the plane is descending to land. The air in the middle ear is at a lower pressure than that of the cabin and if the Eustachian tube becomes blocked the ear drum will be pulled inward resulting in discomfort. This doesn’t usually result in damage to the middle ear or ear drum and usually the Eustachian tube will clear after a short time, but it can be painful. (This is especially common for babies and young children).

Minimise the risks when flying

The Eustachian tubes do not open effectively when you are asleep, so make sure you are awake during the descent.
Keep swallowing at regular intervals to clear the ear. Sipping water, sucking on a lolly or chewing bubble gum may also help; or try an exaggerated yawn.
Avoid flying with a cold or with advice from your doctor, use decongestant drops or spray before and during the flight.
Use ‘Earplanes’ earplugs which may help to modify the effects of pressure changes in the aircraft cabin. These come in both child and adult sizes and are available from chemists and travel goods shops.
Pressure changes from flying may impact on a person’s tinnitus by changing the loudness and pitch of the tinnitus but these changes are generally only temporary. Some people also find the cabin noise aggravates their tinnitus for short time. ‘Earplanes’ plugs may help to exclude unwanted noise as well as modifying air pressure changes.
For further information please read the article ‘Flying and the ear’ by the British Tinnitus Association: http://www.tinnitus.org.uk/flying-and-the-ear

How pressure affects your ears during underwater diving

When diving, tinnitus can be a symptom of serious changes to the auditory system that have occurred because of the effects of underwater pressure. There a many types of ear injuries which can cause this.
Middle Ear Squeeze is when a person’s Eustachian tube doesn’t clear after they come up from a dive. It may cause them to feel dizzy and their ears feel full or blocked.
Alternobaric Vertigo occurs when the middle ear on one side of a person’s head clears more easily than the other side and can result in the pressure in one ear being different from the other. A person will start to feel like they are spinning and may become disorientated and vomit. This is very dangerous if it happens while a person is on a dive.
Barotrauma occurs when a person fails to equalise the air pressure in their middle ear/s. This usually occurs where the higher pressure in the external ear bruises the eardrum or makes it rupture.
Decompression Sickness is where bubbles of gas form in a person’s body as they ascend from a dive. This may form in the hearing or balance system. Deafness, tinnitus, nystagmus, dizziness and vomiting can be symptoms of this illness.

Minimise the risks when underwater diving

Don’t go underwater diving if you can’t clear your ears. This may happen if you have a cold and your Eustachian tubes are not functioning as well as they should. To clear the ears use the val salva manoeuvre. Take a small breath, close your mouth, pinch the nose closed between your finger and thumb and gently try to blow air out the nose.
If you experience tinnitus after diving, consult an Audiologist, GP or ENT for further assessment.
For further information please contact an audiologist, GP or ENT & read the article by scuba-doc on tinnitus: http://www.scuba-doc.com/entprobs.html#Tinnitus

Temporomandibular joint disorder (TMJ)
  • Do you have pain in and around the jaw?
  • Do you often get headaches for no apparent reason?
  • Do you have difficulty opening and closing your mouth?
  • Do you experience clicking or grating when you open or close your mouth?
  • Does your jaw sometimes lock?
  • Have you ever had pain in a perfectly healthy tooth?
  • Do you clench and grind your teeth at night?
  • Do you have sore or tired jaws when you wake up in the morning?
  • Do you have pressure behind your eyes or tearing for no apparent reason?
  • Do you experience sinus pain?

If you answered yes to any of these questions you may have a TMJ disorder.

What is TMJ disorder?

TMJ disorder refers to disorders of the jaw joint, or the Temporo-Mandibular Joint. The term may also be used to refer to the muscles and soft tissues around the joint area.
The jaw joint is at the side of your face, just in front of your ear and can be felt moving as you open and close your mouth. It is one of the body’s most anatomically complex joints. There can be a relationship between jaw and neck problems.
Other names for the condition are MPD (Myofascial Pain Dysfunction) or CMD (Cranio-Mandibular Disorder). TMJ disorder can cause pain deep in the ear and may aggravate tinnitus.

Causes of TMJ disorders
  • Predisposing factors: past health or development, e.g. born with a jaw malformation, had an early accident or blow to the head, been a thumb-sucker
  • Precipitating factors: an unusual event which sets off your TM disorder, e.g. direct blow to the face, chin or jaw, whiplash or other indirect trauma; surgical or dental trauma
  • Perpetuating factors: faulty habits which prolong the existence of the problem, e.g. chewing gum, clenching the jaw, grinding the teeth at night, abnormal muscle habits, posture stress or tension.
Treatment for TMJ disorders

In almost all cases pain can be alleviated and the problems can be managed effectively. Because it is a chronic condition, changes in lifestyle and habits are necessary to obtain good sustainable results from treatment.

Some people have to learn to live with some inconvenience, e.g. a click or occasional discomfort, especially if there is joint damage. You can learn ways to minimise these inconveniences. In a very few cases, surgery is a viable option. As a rule, the longer you avoid treating the problems the longer it takes to get better,

Treatment is best shared between your Dentist (or Dental Specialist) and a therapist who is trained in TMJ and is able to assist you with long-term management. There are also self-help guides available which help to alleviate some of the problems by managing associated behaviours.

Treatments can include:

  • Physiotherapy: freeing stiff or restricted movement, massage for myofascial release, treatment of related factors such as spinal or biomechanical disorders, headache, posture and movement disorders
  • Gentle yoga or Tai Chi: provides relaxation, mobilizes stiff joints and improves posture
  • Relaxation training: progressive relaxation training or meditation
  • Dental Splint: a removable plastic bite-plate that fits over either the upper or lower teeth to help break the habit of clenching and encouraging normal jaw movement.
More information

Book: “Taking Control of TMJ” Robert Uppgaard, Dentist

Acknowl. R O Uppgaard “Taking Control of TMJ”; Lynn Haysmann, Physio Plus

Some women report that their tinnitus started or became more noticeable during pregnancy, menopause or hormone replacement therapy.  However, these life events are not widely regarded as causes or aggravators of tinnitus.

Pregnancy and tinnitus

While hormonal changes during pregnancy may have an unknown influence upon tinnitus, it is likely that any increased tinnitus awareness is related to other factors that are known to aggravate tinnitus distress, such as:

  • Depression, for instance, is known to interact with tinnitus and so depression during pregnancy or after childbirth may have been a factor for some women. Also, some medical treatments given for depression are known to aggravate tinnitus awareness in some individuals.
  • Emotional stress and fatigue can also aggravate tinnitus awareness. The mother of a new baby often has inadequate sleep and may be experiencing stress associated with the adjustment to parenting. This fatigue and stress can contribute to tinnitus annoyance.
  • Moreover, many people with tinnitus are more aware of tinnitus when it is quiet, particularly at night, and it may interrupt or prevent sleep. Women who are waking to feed infants during the night might then be more aware of their tinnitus because of the relatively low levels of background sounds.
Ear pathology

A condition of the middle ear which can become worse during pregnancy is otosclerosis. Otosclerosis is a disease that eventually prevents the middle ear bones from conducting signals to the inner ear, resulting in hearing loss. Tinnitus is often associated with otosclerosis. A surgical procedure can correct the hearing loss and may reduce tinnitus awareness in this situation.

Menstrual cycle

For some women, the menstrual cycle may plays a significant part in tinnitus severity fluctuations. It is thought, in part, to be due to the hormone levels released during certain times of the cycle phase.

Hormone Replacement Therapy and tinnitus

Some women have reported that they first became aware of their tinnitus during a course of Hormone Replacement Therapy (HRT). HRT involves the taking of supplementary female sex hormones to relieve menopausal symptoms and to reduce the future risk of osteoporosis and cardiovascular disease.
There are a number of reasons why these women may have noticed an association between HRT and tinnitus awareness:

  • Tinnitus is much more common is people in middle to later life than it is in younger people, so increased tinnitus awareness may occur coincidentally with other age-related factors
  • Changes in the levels of hormones circulating in the body during menopause may affect tinnitus awareness through some unknown action
  • Tinnitus annoyance may be aggravated by some symptoms of menopause such as mood changes
  • HRT has possible side effects that could contribute to tinnitus awareness. These side effects include: fluid retention, insomnia, depression, headache, dizziness and raised blood pressure
  • Tinnitus can be a symptom of pre-menopausal syndrome and may be aggravated by some of the constituents of the HRT prescribed for this condition
  • HRT may speed up the progress of otosclerosis, potentially aggravating the tinnitus and also causing a progressive hearing loss which reduces effectiveness of external sounds in masking the tinnitus

There is ongoing research into many aspects of HRT. Your Doctor can discuss with you the different brands and forms of HRT with you and advise you about all your prescription medicines.