Man Files $15 million Lawsuit Against NYC Citi Bike Claiming Smell Loss From Bike Crash

Image by Pharos of Wikipedia

In 2013, a man rented a bicycle from New York City's Citi Bike program. Apparently while riding this rental bike, the front wheel struck a wheelstop installed near a bicycle docking station which the man did not notice, flipping him resulting in head trauma. This head trauma resulted in permanent smell and taste loss. [link]

The wheelstop is meant to prevent cars from from backing into bike stations, but the lawsuit alleges "no cones or colored warnings to alert a bicyclist of its existence... constituted a trap for the unwary."

Regardless of the legal merits of the case, how does head trauma like this cause smell and taste loss?

The smell nerve is located right between the eyes and is analogous to the roots of a plant where the plant is the nerve next to the brain and the roots are the nerve endings that go through the skull bone (cribiform plate) and into the nose where "smell" is detected (the yellow in pic below). With significant head trauma, the brain suddenly moves and "bounces" around in the skull when struck. When this happens, the delicate smell nerve endings which are going through the bone "tear" when the brain moves relative to the bone.

With such nerve damage, smell can be permanently lost. With complete smell loss, taste can be adversely affected given so much of flavor is attributable to smell. As such, the man can technically probably still taste (salt, sweet, sour, bitter, etc), but not smell.

BTW... Did you know that the tongue taste map we all learn in school is incorrect?


Source:
Conn. man files $15 million lawsuit against NYC, Citi Bike, claiming nerve damage from bike crash. Daily News 2/27/14

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30% of Patients with Reflux will NOT Respond to Medications

Specifically, patients who are suffering with throat symptoms of reflux will often not respond to proton-pump inhibitor (PPI) medications. Such throat symptoms include throat-clearing, phlegmy throat, cough, hoarseness, and globus. Known as LPR (laryngopharyngeal reflux), a study was done measuring the pH at the throat level after 4+ weeks of twice daily PPI.

This retrospective study found that although 67.4% had symptom normalization, 32.6% of patients showed no subjective or objective treatment response. For all patients whose symptoms did not normalize, pH scores also did not normalize.  For individuals whose symptoms normalized but whose pH scores did not normalize, there was a significant decrease in upright pH score.

Based on these findings, one should NOT assume that lack of response to reflux medications indicative of reflux being an incorrect diagnosis. Further study with a pH or impedance monitoring should be performed in non-responders to help figure out what is going on.

Reference:
Effects of Proton Pump Inhibitor Therapy for Laryngopharyngeal Reflux on Posttreatment Symptoms and Hypopharyngeal pH. Otolaryngol Head Neck Surg. 2014 Mar 19. [Epub ahead of print]

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Device that Allows Intubated Patients to Talk

Image by Calleamanecer in Wikipedia

There is nothing worse than to be very sick. It's even worse if you are intubated in the ICU (intensive care unit) being poked and prodded constantly. Traditionally, such sick intubated patients (if alert) will communicate by writing on a clipboard which is often frustrating to not just the patient, but also family members and healthcare professionals trying to care for the patient.

However, NEJM reported on the use of an electrolarynx to allow intubated patients to "talk". Electrolarynx is traditionally used by patients who have had their voicebox removed due to cancer (laryngectomy). Held similarly to a razor, a patient is able to talk by mouthing words while pressing the electrolarynx against the neck The electrolarynx produces vibrations within the throat that allows for speech sounds. See video below to see how it works.

Apparently, this device can also be used by intubated patients to communicate with caregivers. According to the article, speech by intubated patients occurred after only 2 minutes of instruction. Optimal placement of the electrolarynx was between the upper trachea and the sternocleidomastoid muscle. A video is shown in the article webpage demonstrating a patient who is intubated talking using an electrolarynx.

Electrolarynx can be purchased on Amazon.com.

Reference:
Speech in an Orally Intubated Patient. N Engl J Med 2014; 370:1172-1173March 20, 2014DOI: 10.1056/NEJMc1313379

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How Ears Tune In and Out Certain Sounds

Ever wonder how humans with normal hearing are able to "hear" what one person is saying in a crowded room where many people are talking? How is it that the ear is able to tune in and out of conversations going around, especially when everybody in a room is talking equally loud?

To understand this ear "tuning" ability, one needs to first understand that the ear incorporates two "aspects" that allow for good hearing: a volume knob and an antenna. Should the volume knob not work, hearing aids boost the frequencies where hearing loss is present. However, if the antenna does not work, simply increasing the volume does not necessarily make sounds/speech more understandable. This situation is analogous to an old radio where turning the volume up on a station with a lot of static does not make sounds more understandable (fiddling with the antenna to get a clear signal is better).

We have a very good understanding the volume knob of the human ear. What we do NOT have a good understanding (nor how to fix) is the antenna.

However, researchers have begun to clarify how the human ear "fiddles" the antenna to make certain sounds more understandable relative to others providing humans the ability to tune into what one person is saying in a loud restaurant.

Apparently, part of the answer is the tectorial membrane found within the cochlea (membrana tectoria in the Gray's illustration below).

Note that this membrane found inside the cochlea rests on the inner and outer hair cells which allow for hearing (the volume knob). When the ear hears a sound, "waves" are created within the cochlea stimulating the hair cells which allow us to hear. Depending on which hair cells are stimulated, a specific sound frequency is heard.

Using mutant mice, MIT researchers have determined that the viscosity of tectorial membrane depends on the size and distribution of tiny pores. This viscosity provides mechanical filtering that helps to sort out specific sounds by influencing the speed and decay of tectorial membrane waves when a sound is heard.

Although the precise way how the tectorial membrane allows for such exquisite frequency selectivity is still not fully understood, this may be the first step towards that comprehension.

Because once we firmly understand how the ear's antenna works, we hopefully can make better hearing aids that not only act as a volume knob, but can also fiddle the antenna as well.

Reference:
Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves. Biophysical Journal, Volume 106, Issue 6, 1406-1413, 18 March 2014 doi:10.1016/j.bpj.2014.02.012

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LeBron James and His Broken Nose

LeBron James suffered a broken nose. He first broke it Feb 2014 when playing against Oklahoma City. He than got hit to the nose again (while wearing a mask) when playing against Houston in March 2014. [link]

Regardless of whether you are an NBA player or not, treatment of most nasal and even facial fractures do NOT require surgical repair.

The key elements that lead towards a decision for facial and/or nasal fracture surgery are the following (not all-inclusive, but general pointers):

- Any functional deficit (i.e., inability to open and close the jaw)
- Change in occlusion (the way teeth come together).
- Double vision (blurry vision does not count).
- Cosmetic deformity due to nasal/facial fracture (bruising and swelling does not count).
- Nasal obstruction not due to swelling.

In any case, when a nose is broken, steps should be taken to further minimize trauma to the nose. For athletes, that usually means wearing a facial mask such that any hits to the face does not connect with the broken nose.

Although LeBron James had his facial mask custom made by Marvel, for us mere mortals, you can buy one on Amazon.

Source:
Just like every other superhero, LeBron has his Kryptonite. Fox Sports 3/5/14

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Permanent Hearing Loss From Noise May Depend on Time of Day!

Research out of Sweden have discovered that noise-induced hearing loss sustained at night is more likely to become permanent than if it occurred during the day... at least in mice.

Apparently, there are certain genes found to cycle in the cochlea of mice in a pattern that followed the hours of the day. By measuring the auditory nerve activity, they found that mice exposed to moderate noise levels during the night suffered from permanent hearing loss while mice exposed to similar noise levels during the day did not. The ability to heal after noise-induced hearing loss (temporary threshold shift) was linked to the circadian rhythm due to levels of BDNF (brain derived neurotrophic factor).

Specifically, concentration of BDNF increases in the cochlea during the day which protected hearing from permanent damage whereas levels were absent at night. Furthermore, researchers were able to artificially increase BDNF levels at night when normally absent and confer hearing protection with noise exposure.

What does this mean for humans?

IF human ears also have a biologic clock similar to mice, than researchers MIGHT be able to develop a specific way to reverse (or prevent) noise-induced hearing loss. Currently, the only way to treat acute noise-induced hearing loss is high doses of steroids whether orally or by injection directly into the ear.

Also, humans should probably avoid listening to loud music at night (i.e. concerts, night-clubs, restaurants, etc) which elevates risk of permanent hearing loss (compared to during the day).

Reference:
TrkB-Mediated Protection against Circadian Sensitivity to Noise Trauma in the Murine Cochlea. Current Biology, 27 February 2014. 10.1016/j.cub.2014.01.047

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Infant Sound Machines for Sleep May Cause Hearing Loss

As a father of two young kids who still use a sound machine to help them sleep, I was quite curious about a recent paper that warned that such devices may cause permanent hearing loss. Researchers compared a total of 65 sounds produced by 14 machines and measured the maximum sound level at a distance of 30 cm (crib-rail placement), 100 cm (beside crib placement), and 200 cm (across room placement).

Why is placement important?

When it comes to risk of hearing loss due to loud noise exposure, there are three factors that come into play: 1) how loud is it; 2) how close is it; 3) how long are you exposed to it. Clearly, a person is at a higher risk for permanent hearing loss the louder a sound is, the closer the sound is, and the longer one is exposed to the loud sound.

When it comes to infant sound machines, two of the three risk factors are typically present given such machines are usually placed in or on the crib (close) and is typically played all night (duration).

Alarmingly, 3 machines produced sound levels 85+dBA which exceeds current occupational limits (if exposed for 8+ hours) for adults in the workplace which would mandate use of hearing protection. All 14 machines were capable of producing noise 50+dBA at distances of 30 and 100cm. 13 machines were capable of 50+dBA at 200 cm.

Which machines were tested? Beyond stating "procured from major online and brick-and-mortar infant-accessory stores," the machines were not identified. I wonder if the authors were fearful of lawsuits from sound machine manufacturers and as such, kept it anonymous.

Of course, one can always try contacting the ENT department at University of Toronto where this research was done and get an off-the-record answer.

Given lack of identification, the main steps a parent can take to minimize noise-induced hearing loss is to:

1) place sound machines as far away from infants as possible
2) set volume as low as possible
3) limit duration of sound machine usage


Reference:
Infant Sleep Machines and Hazardous Sound Pressure Levels. Published online March 3, 2014 (doi: 10.1542/peds.2013-3617)

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Flushing Ears with Cold Water Can Treat Somatoparaphrenia

Somatoparaphrenia is a condition whereby a person denies that a limb or an entire side of the body belongs to them, even if provided with irrefutable proof. This condition usually is accompanied by left-sided paralysis and anosognosia (denial or lack of awareness) of the paralysis often due to a parietal stroke.

What is interesting is that flushing the left ear with cold water (caloric vestibular stimulation) can temporarily treat/resolve somatoparaphrenia. Specifically, the protocol is flushing into the left ear canal 60cc of cold water (20 degrees Celsius) for one minute. During the stimulation, the patient is laid down and head tilted forward 30 degrees. If properly done, clear horizontal nystagmus with leftward slow phase can be seen for about 3 minutes.

Normally, flushing the ear in this manner is routinely performed as part of balance testing (ENG) to determine whether a person's dizziness is due to an inner ear problem or not.

In any case, how does vestibular stimulation help with somatoparaphrenia? I don't quite understand it myself, but according to one reference:

"vestibular input takes part in building up and updating the representation of egocentric space." [link]

Whatever that means...

References:
Can vestibular caloric stimulation be used to treat apotemnophilia? Med Hypotheses. 2007;69(2):250-2. Epub 2007 Feb 9.

Partial Remission of Hemiplegia and Somatoparaphrenia Through Vestibular Stimulation in a Case of Unilateral Neglect. Cortex Volume 28, Issue 2, June 1992, Pages 203–208

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