What? Gait and hearing....

No, not how does the gait SOUND, but can they hear? We have long payed attention to the mechanics of gait, muscles and proprioception, and many times, if you have been following us for any length of time, the interplay of all three. But how often have you considered someones hearing in your evaluation?

Anatomically, the hearing organs (hair cells, otolithic apparatus, cochlea) are conveniently located right next store to the vestibular system (utricle, saccule and semicircular canals). The hearing organs start with mechanical vibrations of the tympanic membrane (ear drum) which move 3 auditory bones (or ossicles) called the incus, malleus and stapes. The vibrations move the stapes moves in and out of the fluid filled cochlea and vibrate crystals laying on a platform (otolith) in which hair cells are imbedded and if the vibration sufficient, the nerves attached to the hair cells fire and you can hear your favorite baseline by Cliff Williams (or Cliff Burton, John Myung, Bootsy Collins or whomever you like to listen to).

The vestibular system, as you probably know, monitors position and velocity of movement of the head. There are three hula hoop type structures called “semicircular canals” (see picture above) that monitor rotational and tilt position and angular acceleration, as well as two other structures, the utricle and saccule, which monitor tilt and linear acceleration.

The vestibular apparatus (the canals and the utricle and saccule) feed into a part of the brain called the floccular nodular lobe of the cerebellum, which as we are sure you can imagine, have something to do with balance and coordination. This area of the cerebellum feeds back to the vestibular system (actually the vestibular nucleii); which then feed back up to the brain as well as (you guessed it) down the spinal cord and to predominantly the extensor muscles.

Can you see how the 2 systems are “attached” to one another and could conceivably be interrelated? When you move fluid in one system (endo or peri lymph) you HAVE to move fund in the other. The fluid displaces, (like air, in air filled shoes or insoles), it does not deform (like EVA in an insole)

It is well established that hearing impaired folks (especially kids) have gait (and often balance) problems (1-3) and the worse the hearing loss, the worse the gait disturbance (1). This can occur in middle aged (4), as well as older adults as well (5-7). Perhaps this is due to viscosity changes in the endo or perilymph (8), otosclerosis of the ossicles (9,10) or other age related changes in utricle and saccule function (5-7). Also, for the 1st time, we are documenting a “sensory reweighting” which occurs when auditory cues are changed (4), with a greater reliance on visual cues. Hmmm. We wonder how this plays out with listening to music while walking or running?

So, The next time someone you see has a gait or balance problem, check their hearing and adjust your treatment program accordingly : )

References:

1. Melo RS.  Gait performance of children and adolescents with sensorineural hearing loss.
Gait Posture. 2017 Jun 3;57:109-114. doi: 10.1016/j.gaitpost.2017.05.031.

2. Jafarnezhadgero AA, Majlesi M, Azadian E. Gait ground reaction force characteristics in deaf and hearing children. Gait Posture. 2017 Mar;53:236-240. doi: 10.1016/j.gaitpost.2017.02.006. Epub 2017 Feb 14.

3. Janky KL, Givens D.Vestibular, Visual Acuity, and Balance Outcomes in Children With Cochlear Implants: A Preliminary Report. Ear Hear. 2015 Nov-Dec;36(6):e364-72. doi: 10.1097/AUD.0000000000000194.

4. Maheu M, Sharp A, Landry SP, Champoux F. Sensory reweighting after loss of auditory cues in healthy adults. Gait Posture. 2017 Mar;53:151-154. doi: 10.1016/j.gaitpost.2017.01.015. Epub 2017 Jan 24.

5. Agmon M, Lavie L, Doumas M. The Association between Hearing Loss, Postural Control, and Mobility in Older Adults: A Systematic Review. J Am Acad Audiol. 2017 Jun;28(6):575-588. doi: 10.3766/jaaa.16044. Review.

6. Layman AJ1, Li C, Simonsick E, Ferrucci L, Carey JP, Agrawal Y. Association Between Saccular Function and Gait Speed: Data From the Baltimore Longitudinal Study of Aging. Otol Neurotol. 2015 Jan 7. [Epub ahead of print]

7. Otol Neurotol. 2012 Jul;33(5):832-9. doi: 10.1097/MAO.0b013e3182545061.
Decline in semicircular canal and otolith function with age.
Agrawal Y1, Zuniga MG, Davalos-Bichara M, Schubert MC, Walston JD, Hughes J, Carey JP.

8. Wu T, Marcus DC. Age-Related Changes in Cochlear Endolymphatic Potassium and Potential in CD-1 and CBA/CaJ Mice . JARO: Journal of the Association for Research in Otolaryngology. 2003;4(3):353-362. doi:10.1007/s10162-002-3026-6.

9. Grayeli AB1, Sterkers O, Toupet M. Audiovestibular function in patients with otosclerosis and balance disorders. Otol Neurotol. 2009 Dec;30(8):1085-91. doi: 10.1097/MAO.0b013e3181b0fd5d.

10. Ozmen AO1, Aksoy S, Ozmen S, Saraç S, Sennaroğlu L, Gürsel B. Balance after stapedotomy: analysis of balance with computerized dynamic posturography. Clin Otolaryngol. 2009 Jun;34(3):212-7. doi: 10.1111/j.1749-4486.2009.01915.x.

Does slowing gait increase gait stability ?

As this study suggests, it has been difficult to find studies that establish a clear connection between gait stability and gait speed. One can easily assume that slowing down increases stability, we do it on slippery surfaces, we do it when a joint is painful, even the elderly do it naturally everyday. Walking speed, step length, step frequency, step width, local dynamic stability , and margins of stability were measured in this study below. It was found that the subjects did not change walking speed in response to the balance perturbations rather they made shorter, faster, and wider steps with increasing perturbation intensity. They became locally less stable in response to the perturbations but increased their margins of stability in medio-lateral and backward direction. 

So what did they conclude ?  Here are their words,“In conclusion, not a lower walking speed, but a combination of decreased step length and increased step frequency and step width seems to be the strategy of choice to cope with medio-lateral balance perturbations, which increases Margins of Stability (MoS) and thus decreases the risk of falling.”

It is my assumption, and this just seems logical, that if the perturbations were to continue constantly, that one would slow the gait speed to reduce the need for these shorter, faster and wider steps. 

Dr. Shawn Allen

http://www.ncbi.nlm.nih.gov/pubmed/22464635

Gait Posture. 2012 Jun;36(2):260-4. doi: 10.1016/j.gaitpost.2012.03.005. Epub 2012 Mar 29.Speeding up or slowing down?: Gait adaptations to preserve gait stability in response to balance perturbations.Hak L¹, Houdijk H, Steenbrink F, Mert A, van der Wurff P, Beek PJ, van Dieën JH.

A Wobble in the System: The Gait Changes in Normopressure Hydrocephalus

Can you afford to miss this diagnosis ? 

Today, the gait changes in NPH are discussed because as with many neurologic disorders and diseases, subtle gait changes are the first signs. And, in this disorder, you have to catch the gait changes early on in order to give your client the greatest changes of full recovery.   Today we couple this blog post with a great video story of a missed case study of NPH.

Normopressure hydrocephalus (NPH) consists of the triad of :

1. gait disturbance
2. urinary incontinence
3. dementia or mental decline

In the most general terms, Normal pressure hydrocephalus (NPH), also referred to as symptomatic hydrocephalus, is caused by a decreased absorption of cerebrospinal fluid (CSF). The resultant increased intracranial pressure can cause ventriculomegaly.  In NPH patients, the pressure remains just slightly elevated, but enough to create pressure on the cortical tissues of the brain causing the symptoms above. The vagueness of this problem and its seemingly random symptoms is primarily why this disorder is often missed or misdiagnosed as dementia, Parkinson’s or Alzheimers disorders.

As discussed previously, many early neurological diseases and disorders softly present with early gait changes. And, as in NPH, gait changes may be the earliest symptom of the 3 mentioned earlier. One’s ability to know, observe and recognize abnormal gait patterns coupled with a good historical interview and physical exam can often tease out the earliest manifestation of NPH.

Here is what you need to know about the gait presentation in NPH:

The gait changes are often subtle and progress as NPH progresses because of the changes in the brains ventricular tissues eventually compromising the sensory-motor tracts.
Early gait changes, MILD, may show a cautious gait. Steps length and stride length may be slowed and shortened. The gait may begin to show signs of being deliberate and calculated, less fluid and free. The appearance of unsteadiness or balance challenges may prevail. Once simple environmental obstacles may now present as challenges, things like curbs, stairs, weaving between tables in restaurants or wide open spaces where there is nothing to grasp onto for stability. Weakness and tiredness of the legs may also be part of the complaint, although examination discloses no paresis or ataxia. (Ropper)  A walking aid such as a cane may add comfort but often appears to be rarely used.

As the gait changes progress into the more MODERATE to ADVANCED, the walking aids used often progress into quad walkers.  Wheelchairs are needed in more difficult places or when fatigue is growing factor.  As the gait challenges progress, the careful observer will note a more obvious reduction in step and stride length, a head down posture, less dual tasking engagement during gait execution, slowed walking speed, reduced foot-floor clearance, shuffling gait (keeping the feet more engaged to the ground, this can be a Parkinsonian-type gait mis-read, there will be no tremor or rigidity), searches for stable external cues (reaching for railings, a kind arm or hand, touching walls etc), widening of the feet (broad based stance), and fears of falling backward.

In the most ADVANCED gait impairments, the fear of falling can become too great. There may even be an inability to engage sit-stand-walk motor patterns and the fatigue of the limbs may be too advanced to even stand let along walk. This stage is referred to as Hydrocephalic astasia-abasia (Ropper).  

Normopressure Hydrocephalus is a serious issue if left unrecognized and untreated. Here is yet another reason why you must be familiar with this problem:

“Patients with dementia who are confined to a nursing home and may have undiagnosed NPH can possibly become independent again once treated. So far only one study was able to evaluate the prevalence of NPH, both diagnosed and undiagnosed, among residents of assisted-living facilities, showing a prevalence in 9 to 14% of the residents.” - Marmarou

One’s lack of awareness and knowledge, are one’s greatest enemies. If you don’t know something exists, because you’ve never studied or learned it, how can you be aware of it ? If you’re not spending enough time examining a client, you might be unaware of an issue even though you may be knowledgeable about the issue. One must have both awareness and knowledge. One must also be aware that compensations are the way of the body. What you see is not your client’s problem. It is their strategy to cope.

NPH must be diagnosed early on since a delay in reducing the pressure on the cortical tissues can lead to permanency of disease and dysfunction.  According to Poca there can be a wide range of successes and failures in symptom remediation, but there is clearly a time dependency on early diagnosis. Thus, clearly recognizing any early gait changes and behaviors prior to advancing incontinence and mental decline is paramount.

Bonus: here is a little bonus tidbit for my fellow neuro gait friends. 

Stolze (7) study conclusion: “The gait pattern in normal pressure hydrocephalus is clearly distinguishable from the gait of Parkinson’s disease. As well as the basal ganglia output connections, other pathways and structures most likely in the frontal lobes are responsible for the gait pattern and especially the disturbed dynamic equilibrium in normal pressure hydrocephalus. Hypokinesia and its responsiveness to external cues in both diseases are assumed to be an expression of a disturbed motor planning.”

Dr. Shawn Allen, … one of “the gait guys”

Some of the above was inspired and summarized by this great article, from the Boston Globe.  

References:

1. Marmarou, Anthony; Young, Harold F.; Aygok, Gunes A. (1 April 2007). “Estimated incidence of normal-pressure hydrocephalus and shunt outcome in patients residing in assisted-living and extended-care facilities”. Neurosurgical FOCUS 22 (4): 1–8.

2. Ropper, A.H. & Samuels, M.A. (2009). Adams and Victor’s Principles of Neurology (9th edition). New York, NY: McGraw-Hill Medical.

3. Poca, Maria A.; Mataró, Maria; Matarín, Maria Del Mar; Arikan, Fuat; Junqué, Carmen; Sahuquillo, Juan (1 May 2004). “Is the placement of shunts in patients with idiopathic normal pressure hydrocephalus worth the risk? Results of a study based on continuous monitoring of intracranial pressure”. Journal of Neurosurgery 100 (5): 855–866.

4. Am J Phys Med Rehabil. 2008 Jan;87(1):39-45.
Objective assessment of gait in normal-pressure hydrocephalus.
Williams MA1, Thomas G, de Lateur B, Imteyaz H, Rose JG, Shore WS, Kharkar S, Rigamonti D.

5. Clin Neurophysiol. 2000 Sep;111(9):1678-86.
Gait analysis in idiopathic normal pressure hydrocephalus–which parameters respond to the CSF tap test?
Stolze H1, Kuhtz-Buschbeck JP, Drücke H, Jöhnk K, Diercks C, Palmié S, Mehdorn HM, Illert M, Deuschl G.

6.Rev Neurol (Paris). 2001 Nov;157(11 Pt 1):1416-9.
[Postural and locomotor evaluation of normal pressure hydrocephalus: a case report]. Mesure S1, Donnet A, Azulay JP, Pouget J, Grisoli F.

7.J Neurol Neurosurg Psychiatry. 2001 Mar;70(3):289-97.
Comparative analysis of the gait disorder of normal pressure hydrocephalus and Parkinson’s disease.
Stolze H1, Kuhtz-Buschbeck JP, Drücke H, Jöhnk K, Illert M, Deuschl G.