By JANE E. BRODY
The New York Times, Published: April 18, 2011
Dr. Ronald DeVere, a neurologist in Austin, Tex., was baffled. In 1995, after recovering from a viral infection, something happened to his sense of smell. Fresh milk smelled sour, the dirty dog pen smelled good, and other odors couldn’t be detected at all.
After weeks passed without improvement, he consulted experts at the University of Pennsylvania Smell and Taste Center, one of 11 such clinics now scattered around the country. Tests there showed that as a result of his illness, he’d lost 70 percent of his ability to smell.
In the years since, Dr. DeVere has recovered much of his ability to smell and taste. But the experience inspired him to open his own clinic for smell and taste disorders and, most recently, to write a book, “Navigating Smell and Taste Disorders” (Demos Health), about this poorly understood and often unrecognized problem.
In an interview, Dr. DeVere said he hoped the book would help not only patients with smell and taste disorders but also their physicians, most of whom know little about these problems, he said, and often tell sufferers that “nothing can be done — you’ll have to live with it.”
The book was written with his sister-in-law, Marjorie Calvert, an accomplished cook who provided a food preparation guide and dozens of recipes — some contributed by patients — that can help restore dining pleasure to those affected. Taste is mostly a result of odor detection, so the recipes emphasize spice, texture and temperature, sensations that remain unimpaired even when smell malfunctions.
You’ve no doubt experienced a temporary disruption in smell and taste while suffering from a cold or sinus infection. Try to imagine your life if the problem lasted indefinitely and you could no longer enjoy the flavor of an orange or chocolate or taste the difference between chicken and steak.
But smell and taste disorders can affect more than the ability to “smell the roses” in life and toenjoy food. Also affected is the ability to detect and correct unpleasant smells, like body odor or a dirty diaper in need of changing. For people like professional cooks and firefighters, the problem can force an occupational switch.
Most important, smell disorders can be downright dangerous for those who cannot detect the odor of smoke, burning or spoiled food, natural gas or other noxious aromas.
An Underrecognized Problem
While reliable statistics are hard to come by, several million Americans are thought to suffer from the major smell disorders: hyposmia, a reduced ability to detect certain odors; anosmia, an inability to detect any odors at all; or dysosmia, in which pleasant odors can smell foul or vice versa.
Most people who think they have a taste disorder, usually because food has lost its flavor, turn out to have a smell problem, according to Richard M. Costanzo, a neurophysiologist at Virginia Commonwealth University. The smell disorders clinic there receives regular inquiries from distressed patients; one of them said his inability to taste food flavors was “a very life-altering experience, and most normal people cannot understand the impact it has on one’s life.”
There are many common causes. In addition to viral infections like colds and flu, they include disorders of the nose (for example, polyps) or sinuses; injuries to the nose or head; medications like blood pressure drugs, antibiotics, cholesterol-lowering drugs, antidepressants and cancer chemotherapy; radiation therapy of the head and neck; exposure to toxins like formaldehyde and pesticides; smoking and alcohol abuse; diseases of the thyroid, kidneys, liver or pancreas; and neurological disorders like Parkinson’s disease, Lewy body disease, multiple sclerosis and various kinds of dementia.
By far the leading cause — and the one least often recognized — is advancing age. Whereas only 1 percent to 2 percent of young people are affected, a quarter of those over 55 and nearly two-thirds of those over 80 have a diminished sense of smell.
But unlike vision or hearing loss, which is often apparent to others, if not to the afflicted person, a loss of smell sensitivity with age is often undetected because it occurs gradually. The result can be a diminished interest in food and gradual weight loss, or a tendency to over-season foods with salt or sugar, which may impair control of high blood pressure or diabetes, common problems in the elderly.
Depending on the cause of a smell disorder, therapeutic possibilities include treatment with nasal decongestants, antihistamines, or antibiotics; surgery to remove nasal polyps; use of a nasal saline solution; correction of hormonal or nutrient deficiencies; and stopping smoking.
Dr. DeVere said that over time smell disorders may gradually diminish in intensity, as his did. Nonetheless, Dr. Costanzo said: “We have to be fair to patients. There’s no magic bullet. Some smell problems are treatable, most are not.”
Especially challenging are those that result from head injuries, whether minor or severe, that disrupt the function of the body’s smell receptors — olfactory nerve cells that lie outside the brain. These cells pick up odor molecules high in the nose and transmit scent messages to the brain’s olfactory bulb, he explained.
A head blow can injure or tear olfactory nerves. Damaged olfactory nerve cells can regenerate, but don’t always reconnect properly in the brain. Dr. Costanzo and colleagues are working on grafts and transplants that may one day overcome current treatment limitations.
While everyone should have working smoke detectors in their homes, a person with a smell disorder should also have a detector for natural gas or propane, lest a leak go undetected and result in an explosion.
Perishable foods should be dated and kept refrigerated, and discarded when they expire. It may be wise for a person with normal olfactory function to check these foods before someone with an impaired sense of smell eats them.
Make sure all cleaning and garden products are properly labeled and stored separately from foods.
When cooking or baking, check periodically to make sure nothing is burning, and set a timer to ring when the food will be done.
Since you can’t rely on a “sniff test,” be sure to bathe and launder clothes regularly. Use underarm deodorant, and go easy with cologne. Regularly check diapers for visual signs that a change is needed.
For more information, consult the Web site of the National Institute on Deafness and Other Communication Disorders at www.nidcd.nih.gov/health/smelltaste.
What is the nose?
The nose is the organ in the middle of the face which performs several functions, including:
- purification of air
- humidification of air
- warming of air
The internal part of the nose lies above the roof of the mouth. The nose consists of:
- external meatus – triangular-shaped projection in the center of the face.
- external nostrils – two chambers divided by the septum.
- septum – made up primarily of cartilage and bone and covered by mucous membranes. The cartilage also gives shape and support to the outer part of the nose.
- nasal passages – passages that are lined with mucous membranes and tiny hairs (cilia) that help to filter the air.
- sinuses – four pairs of air-filled cavities, also lined with mucous membranes.
The nose is the organ of smell and a main passageway for air into and out of the lungs. The nose warms, moistens, and cleans air before it enters the lungs. The bones of the face around the nose contain hollow spaces called paranasal sinuses. There are four groups of paranasal sinuses: the maxillary, ethmoid, frontal, and sphenoid sinuses. Sinuses reduce the weight of the facial bones and skull while maintaining bone strength and shape. The air-filled spaces of the nose and sinuses also add resonance to the voice.
The supporting structure of the upper part of the external nose consists of bone, while the lower part consists of cartilage. Inside the nose is the nasal cavity, which is divided into two passages by the nasal septum. The nasal septum is composed of both bone and cartilage and extends from the nostrils to the back of the throat. Bones called nasal conchae project into the nasal cavity, forming a series of folds (turbinates). These folds greatly increase the surface area of the nasal cavity. Polyps may develop between the folds, often in people with asthma, allergies, or cystic fibrosis and in those using aspirin for long periods.
Lining the nasal cavity is a mucous membrane rich with blood vessels. The increased surface area and the many blood vessels enable the nose to warm and humidify incoming air quickly. Cells in the mucous membrane produce mucus and have tiny hairlike projections (cilia). Usually, the mucus traps incoming dirt particles, which are then moved by the cilia toward the front of the nose or down the throat to be removed from the airway. This action helps clean the air before it goes to the lungs. Sneezing automatically clears the nasal passages in response to irritation, just as coughing clears the lungs.
Like the nasal cavity, the sinuses are lined with a mucous membrane composed of cells that produce mucus and have cilia. Incoming dirt particles are trapped by the mucus, then moved by the cilia into the nasal cavity, through small sinus openings (ostia). Because these openings are so small, the drainage can easily be blocked by conditions such as colds or allergies, which produce swelling of the mucous membranes. Blockage of normal sinus drainage leads to sinus inflammation and infection (sinusitis).
A Look Inside the Nose and Throat
One of the most important functions of the nose is its role in the sense of smell. Smell receptor cells are located in the upper part of the nasal cavity. These cells are special nerve cells that have cilia. The cilia of each cell are sensitive to different chemicals and, when stimulated, create a nerve impulse that is sent to the nerve cells of the olfactory bulb, which lies inside the skull just above the nose. The olfactory nerves carry the nerve impulse from the olfactory bulb directly to the brain, where it is perceived as a smell.
The sense of smell, which is not fully understood, is much more sophisticated than the sense of taste. Distinct smells are far more numerous than tastes. The subjective sense of taste while eating (flavor) involves taste and smell (see as well as texture and temperature. This is why food seems somewhat tasteless when a person has a decreased sense of smell, as may occur when the person has a cold. Because the smell receptors are located in the upper part of the nose, normal breathing does not draw much air over them. Sniffing, however, increases the flow of air over the smell receptor cells, greatly increasing their exposure to odors.
by Harold C. Pillsbury III, MD; Austin S. Rose, MD
NIH: Smelling and the Nose
Smell – impaired
URL of this page: http://www.nlm.nih.gov/medlineplus/ency/article/003052.htm
Anosmia is impaired smell, which can be the partial or total loss of the sense of smell.
The loss of smell can occur as a result of nasal congestion or blockage of the nose and isn’t serious, but it can sometimes be a sign of a nervous system (neurological) condition.
Some loss of smell occurs with aging. In most cases, there is no obvious or immediate cause, and there is no treatment.
The sense of smell is often lost with disorders that prevent air from reaching the part of the nose where smell receptors are located (the cribriform plate, located high in the nose). These disorders may include nasal polyps, nasal septal deformities, and nasal tumors.
Other disorders that may cause a loss of the sense of smell include:
- Alzheimer’s dementia
- Disorders of the endocrine system
- Head trauma
- Nervous disorders
- Nutritional disorders
- Tumors of the head or brain
Many medications may change or decrease the ability to detect odors.
The sense of smell also enhances your ability to taste. Many people who lose their sense of smell also complain of a loss of the sense of taste. Most can still tell between salty, sweet, sour, and bitter tastes, which are sensed on the tongue. They may not be able to tell between other flavors. Some spices (such as pepper) may affect the nerves of the face and may be felt rather than smelled.
- Use of certain medications (such as amphetamines, estrogen, naphazoline, phenothiazines, prolonged use of nasal decongestants, reserpine, and possibly zinc-based products)
- Head injury
- Lead poisoning
- Nasal or sinus surgery or disease
- Natural aging process
- Radiation therapy
- Recent viral upper respiratory infection
- Tumors of the nose or brain
Treating the cause of the problem may correct loss of the sense of smell. Treatment can include:
- Antihistamines (if the condition is related to allergy)
- Changes in medication
- Surgery to correct blockages
- Treatment of other disorders
Avoid using too many nasal decongestants, which can lead to recurring nasal congestion.
If you lose your sense of smell, you may have changes in taste. But, adding highly seasoned foods to your diet can help stimulate the taste sensations that you still have.
Improve your safety at home by using smoke detectors and electric appliances instead of gas ones. You may not be able to smell gas if there is a leak. Or, install equipment that detects the presence of gas fumes in the home.
There is no treatment for loss of smell due to aging.
If you have a loss of smell due to a recent viral upper respiratory infection, be patient. The sense of smell may return to normal without treatment.
When to Contact a Medical Professional
Call your health care provider if the loss of smell continues, is getting worse, or if you have other unexplained symptoms.
What to Expect at Your Office Visit
The doctor will perform a physical exam and ask questions about your medical history and current symptoms. Questions may include:
- Time pattern
- When did this problem develop?
- Have you always had problems with your sense of smell?
- Is the problem getting worse?
- Are all odors affected or only certain types?
- Can you taste food?
- Aggravating factors
- Do you have a cold or other upper respiratory infection?
- Do you have allergies?
- Do you have chronic sinusitis?
- What medications do you take?
- What other symptoms do you have?
The doctor will look at your nose and surrounding structures. Tests that may be performed include:
In some cases, surgery (biopsy) to remove a piece of the cells responsible for smell (olfactory epithelium) may be needed to make a diagnosis.
If the loss of sense of smell is caused by a stuffy nose (nasal congestion), decongestants or antihistamines may be prescribed.
A vaporizer or humidifier may prevent mucus from drying and improve nasal discharge.
Steroid nasal sprays or pills may be recommended.
Vitamin A may be given by mouth or with a shot (injection).
Loss of smell; Anosmia
Loss of Taste & Smell Stinks!
Howard Levine, M.D.
Mt. Sinai Nasal-Sinus Center, Cleveland, OH
American Rhinologic Society
Remember holding your nose when your mother was about to give you a spoonful of medicine? Even as a child you realized the close relationship between what you taste and what you smell.
If your favorite eating pleasures have lost their delicious taste, it is usually a decreased sense of smell that is to blame.
Taste and Smell Go Together
The senses of taste and smell are intimately linked to one another. Often the loss of one will result in the loss of the other.
For many people the problem may be a minor annoyance because they are saddened from the loss of the scent of a rose or a favorite cooking aroma. But for others, the loss of taste and small can actually be quite a serious matter.
The inability to smell a gas leak, a smoldering fire or other noxious odors like spoiled food can be very dangerous.
Taste and smell disorders are common. It is estimated that more than two million Americans have a smell and taste disorder. Because of this problem, approximately 200,000 people visit a physician each year.
What Causes Loss of Smell?
The most common causes for loss of sense of taste and smell are the result of a nasal obstruction, such as the common cold, breathing allergies and nasal congestion from irritants like cigarette smoke and pollutants.
Nasal polyps, small non-cancerous growths in the nose and sinuses, can block the ability for aromas to reach the nerves high up in the nose which allow a sense of smell.
Previous surgery or a blow to the head can upset your sense of smell because the nerves of smell may be damaged or blocked by scar tissue.
Occupational exposure to chemicals may also lessen the sense of smell and certain medications can also affect the sense of smell.
Also, as we get older, like vision and hearing, the sense of smell becomes less accurate.
In rare instances, benign nonmalignant tumors grow on the nerves of smell and should be identified and removed.
How is loss of sense of smell evaluated?
It is difficult to test the sense of taste or smell, but some “scratch and sniff” and taste tests do exist.
A nasal examination with a nasal telescope (also called an endoscope), which illuminates and magnifies the areas of the nose where problems can occur, often will indicate the problem and direct your physician to select an appropriate treatment.
An X-ray, usually CAT scan, is needed to look at the sinuses and noses and areas of the nerves for smell. This should be done by an expert in nose and sinus problems.
While most people who experience a loss of their sense of smell may only be aware of the sensory loss many will also notice loss or change in taste since much of taste is smell.
Decreased Sense of Smell
For some people, it is not an actual loss, but rather an alteration in some smells or taste. Other people become aware of odors which are actually not really present. These phantom “can be very annoying.
What Can I Do?
Wait it out. If you have had a cold with a stuffy nose, chances are a few days wait will see your sense of smell return.
Sweat it out. If your nose is stuffed up from a cold, mild exercise or a hot shower may “open it up.”
Stop Smoking. Smoking causes long-term damage to the sense of smell. If you quit smoking, you may notice some improvement.
Check with a physician. If your sense of smell seems to have disappeared or changed, consultation with an ear, nose and throat physician is a good idea.
A sinus infection can block your sense of smell and depending on the cause of the sinus infection, a more serious condition may be present.
Can Modern Technology Help Me?
With today’s modern nasal telescopes, an expert nasal physician can visually examine the intricate sinus passages and determine very exactly the causes of a blocked nasal airway.
Sometimes a short period of time on antibiotics will remedy the problem. Sometimes, outpatient surgery procedure is necessary.
Whatever the cause, no one needs to be troubled from not knowing the cause of a loss of sense of taste or smell.
Insight into important senses
Problems with these senses have a big impact on our lives. Smell and taste contribute to our enjoyment of life by stimulating a desire to eat – which not only nourishes our bodies, but also enhances our social activities. When smell and taste become impaired, we eat poorly, socialize less, and feel worse. Smell and taste warn us of dangers, such as fire, poisonous fumes, and spoiled food. Loss of the sense of smell may indicate sinus disease, growths in the nasal passages, or, at times, brain tumors.
How do smell and taste work?
Smell and taste belong to our chemical sensing system (chemosensation). The complicated process of smelling and tasting begins when molecules released by the substances around us stimulate special nerve cells in the nose, mouth, or throat. These cells transmit messages to the brain, where specific smells or tastes are identified.
- Olfactory (smell nerve) cells are stimulated by the odors around us—the fragrance from a rose, the smell of bread baking. These nerve cells are found in a tiny patch of tissue high up in the nose, and they connect directly to the brain.
- Gustatory (taste nerve) cells are clustered in the taste buds of the mouth and throat. They react to food or drink mixed with saliva. Many of the small bumps that can be seen on the tongue contain taste buds. These surface cells send taste information to nearby nerve fibers, which send messages to the brain.
Our body’s ability to sense chemicals is another chemosensory mechanism that contributes to our senses of smell and taste. In this system, thousands of free nerve endings—especially on the moist surfaces of the eyes, nose, mouth, and throat—identify sensations like the sting of ammonia, the coolness of menthol, and the “heat” of chili peppers.
What causes loss of smell and taste?
Scientists have found that the sense of smell is most accurate between the ages of 30 and 60 years. It begins to decline after age 60, and a large proportion of elderly persons lose their smelling ability. Women of all ages are generally more accurate than men in identifying odors.
Some people are born with a poor sense of smell or taste. Upper respiratory infections are blamed for some losses, and injury to the head can also cause smell or taste problems.
Loss of smell and taste may result from polyps in the nasal or sinus cavities, hormonal disturbances, or dental problems. They can also be caused by prolonged exposure to certain chemicals such as insecticides, and by some medicines.
Tobacco smoking is the most concentrated form of pollution that most people are exposed to. It impairs the ability to identify odors and diminishes the sense of taste. Quitting smoking improves the smell function.
Radiation therapy patients with cancers of the head and neck often complain of lost smell and taste. These senses can also be lost in the course of some diseases of the nervous system.
Patients who have lost their larynx (voice box) commonly complain of poor ability to smell and taste. Laryngectomy patients can use a special “bypass” tube to breathe through the nose again. The enhanced air flow through the nose helps smell and taste sensations to be re-established.
How are smell and taste loss diagnosed?
The extent of loss of smell or taste can be tested using the lowest concentration of a chemical that a person can detect and recognize. A patient may also be asked to compare the smells or tastes of different chemicals, and how the intensities of smells and tastes grow when a chemical concentration is increased.
- Smell—Scientists have developed an easily administered “scratch-and-sniff” test to evaluate the sense of smell.
- Taste—Patients react to different chemical concentrations in taste testing; this may involve a simple “sip, spit, and rinse” test, or chemicals may be applied directly to specific areas of the tongue.
Can these disorders be treated?
Sometimes certain medications are the cause of smell or taste disorders, and improvement occurs when that medicine is stopped or changed. Although certain medications can cause chemosensory problems, others—particularly anti-allergy drugs—seem to improve the senses of taste and smell. Some patients, notably those with serious respiratory infections or seasonal allergies, regain their smell or taste simply by waiting for their illness to run its course. In many cases, nasal obstructions, such as polyps, can be removed to restore airflow to the receptor area and can correct the loss of smell and taste. Occasionally, chemosenses return to normal just as spontaneously as they disappeared.
How do you cope with smell or taste problems?
If you experience problems in smelling or tasting, try to identify and record the circumstances surrounding it. When did you first become aware of it? Did you have a cold or flu then? A head injury? Were you exposed to air pollutants, pollens, danders, or dust to which you might be allergic? Is this a recurring problem? Does it come in any special season, like hayfever time?
Bring all this information with you when you visit a physician who deals with diseases of the nose and throat (an otolaryngologist—head and neck surgeon). Proper diagnosis by a trained professional can provide reassurance that your illness is not imaginary. You may even be surprised by the results. For example, what you may think is a taste problem could actually be a smell problem, because much of what you taste is really caused by smell.
Diagnosis may also lead to treatment of an underlying cause for the disturbance. Remember, many types of smell and taste disorders are reversible.
Four commonly identified taste sensations:
Certain tastes combine with texture, temperature, and odor to produce a flavor that allows us to identify what we are eating.
Many flavors are recognized through the sense of smell. If you hold your nose while eating chocolate, for example, you will have trouble identifying the chocolate flavor, even though you can distinguish the food’s sweetness or bitterness. This is because the familiar flavor of chocolate is sensed largely by odor. So is the well known flavor of coffee. This is why a person who wishes to fully savor a delicious flavor (e.g., an expert chef testing his own creation) will exhale through his nose after each swallow.
Taste and smell cells are the only cells in the nervous system that are replaced when they become old or damaged. Scientists are examining this phenomenon while studying ways to replace other damaged nerve cells.
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Introduction to Nasal Endoscopy
Martin J. Citardi, M.D.
The Nasal Telescope
The nasal telescope is an optical instrument for examining the nose. This examination is known as diagnostic nasal endoscopy. Because the telescope is so slender (only 2.7-4.0 mm in diameter), it may be passed easily through the nostril to examine the nasal passages and the sinuses. In some nasal telescopes, the view is straight ahead from the tip of the instrument; in other telescopes, the view is at an angle from the tip of the telescope. These ‘angled’ telescopes can be used to see around corners–much like a child’s toy periscope. The standard nasal examination is quite limited; however, nasal endoscopy provides a detailed examination of both the nasal cavity and sinuses. Also, nasal telescopes are also used during surgical procedures in the office and operating room.
Nasal Endoscopy Room
Nasal endoscopy is commonly performed in the office of otorhinolaryngologists (ENT doctors). The ENT doctor can look directly through the telescope. Alternatively, a medical video camera can be attached to the telescope, and then the images are viewed on a special video monitor as shown here. The examination may be recorded on a VCR, or a digital image archive (like a digital camera) may be used. If a patient wishes, he or she may view the images from his or her own examination.
Patients tolerate nasal endoscopy very well. Many ENT doctors will apply a topical nasal decongestant and numbing medicine to the lining of the nose by a nasal spray prior to endoscopy. Often, the examination can be completed without any special medicines at all.
These instruments are designed to be used in the nose and sinuses during nasal endoscopy. They may be used both in the operating room and in the office.
Nasal Irrigation an Easy Way to Relieve Congestion
Dear Mayo Clinic:
Can nasal irrigation help relieve nasal and sinus congestion?
Yes. Nasal irrigation, also called nasal lavage, is a safe, inexpensive and easy way to relieve symptoms of nasal and sinus congestion, such as stuffiness, dry nose and thick mucus. It works in children and adults, and you can do it yourself.
Nasal irrigation involves rinsing out nasal passages with salt water (saline). Rinsing flushes out thickened mucus and irritants, such as dust and allergens, from the nose. It may also help ease swelling in the lining of nasal passages. You can make an irrigation solution by dissolving 1/8 teaspoon of table salt into 8 ounces of warm (about body temperature) water. Or, saline nasal solutions are sold over-the-counter.
To perform nasal irrigation, use a bulb syringe to draw up the saline solution from a bowl. While leaning over a sink, gently place the tip of the syringe into your nose. Don’t insert it all the way inside. Instead, insert the syringe a distance equal to the width of your fingertip. Angle the tip of the syringe toward the top of the ear on the same side, then slowly squeeze the bulb so the liquid gently squirts into your nose. Let the solution drain from your nostril. It may come out of your other nostril or from your mouth. Irrigate both sides of your nose, using two full syringes of solution in each nostril.
After each use, clean the syringe thoroughly to prevent bacteria growth. Fill it with fresh, clean water, and then squeeze out the fluid. Repeat several times until the water coming out is clear. Dry the bulb syringe and store it tip-down in a clean cup so it drains completely.
If you prefer not to use a bulb syringe, other tools are available for nasal irrigation. For example, over-the-counter sinus rinse kits include saline nasal solution and a rinse bottle that you fill with the solution and then squeeze into your nostrils. Sinus irrigators are another alternative. These devices gently force the saline through your nostrils.
One popular option for nasal irrigation is a special container called a neti pot. Fill the neti pot with warm salt water or an over-the-counter saline nasal solution. Then tilt your head over the sink, place the spout of the neti pot in the upper nostril, and lift up the pot so that saline flows into your nose. The salt water will flow through your nasal cavity and out the lower nostril. Repeat on the other side.
Sinus rinse kits, sinus irrigators and neti pots are available online and in most pharmacies and health food stores. If you buy one of these products, follow the label instructions carefully.
Nasal irrigation can be performed several times a day, if needed to relieve symptoms. Most people find that nasal irrigation effectively eases congestion when used regularly. Research comparing nasal saline sprays with nasal irrigation found that nasal irrigation provided greater relief. The reason may be that nasal irrigation uses a greater volume of salt water and may be better at flushing out mucus and irritants.
If you have any questions about nasal irrigation, or if your nasal symptoms don’t improve, talk to your doctor.
— Daniel Blum, M.D., Otorhinolaryngology, Mayo Clinic, Rochester, Minn.