BPPV revisited

A while back I wrote about Benign Paroxysmal Positional Vertigo or BPPV for short. It is a condition which although not life threatening is common, profoundly disturbing, often anxiety producing and inadequately treated. A sense of balance is fundamental to normal day to day activity and this problem doesn't just make you feel 'off' as many spinal problems can do. BPPV is a sudden and disturbing spinning sensation (most often associated with movement such as rolling over in bed) accompanied by nausea, sweating and anxiety and visual disturbance. Futhermore even once an attack has passed the experience is such that most people remain highly anxious or hypervigilant. This in itself is a normal response by the brain which has evolved to force you to pay particular attention to sensations which may threaten your survival and falling over is a main one. Think of the times your pesky brother sneaked up on you at lovers leap. Now magnify that sensation of threat, add in a manic childs roundabout and you have BPPV.

Fortunately it's diagnosis is easily confirmed and 90% respond well to treatment. In contrast is Menieres disease which is currently thought to be due to a disturbance in the fluid of the inner ear (endolymph).

Ds

The neck and balance disturbance

The causes of balance disturbance are many but one of the most common is injury, strain or overuse of the neck joints.

Why?  Along with the inner ear and vision the neck joints deliver a constant stream of information to the brain regarding balance (officially orientation in 3 dimensional space).

Diagnosis

Most of our suspicions regarding what is causing the problem come from a history of accidents involving the head and neck where the person has been medically cleared but symptoms persist. Patients typically feel uneasy or 'off', often describe minor visual issues such as keeping focus on computer screens and perform poorly when balance is challenged. If they also present with neck stiffness or clicking there is a very good chance they will respond well when neck movement is improved. In addition some patients require corrective exercises.

The most recent case was the father of a young child who slipped down some stairs. He was essentially uninjured except for a jolted neck and mild concussion. The hospital had cleared him for serious injury and the neck was only slightly uncomfortable but he also began having trouble with 'eye strain' at work, mild headache and poor concentration. His brain scan had been normal after the fall so he hadn't connected his symptoms. His balance was poor particularly when we asked him to close his eyes and tests for inner ear trouble were negative. He responded well to gentle spine mobilisation and didn't require exercises.

Doug Scown

Core Myths

Is your ab workout hurting your back?

Jun 17, 2009 - Filed in: Back PainReynolds G. New York Times 2009, June 17

In subjects with healthy backs, the transverse abdominis (TrA) contracts milliseconds before the deltoid when raising the arm into flexion. The nervous system activates the TrA to brace the spine in advance of movement. In LBP patients TrA firing was delayed. LBP patients were trained to isolate & strengthen the TrA by sucking in their abdomen & a booming industry of fitness classes was born. The idea leaked into gyms & Pilates classes that core health was “all about the TrA.” But there’s growing dissent among sports scientists about whether all this attention to the TrA gives you a stronger core/ back & whether it’s even safe. “There’s so much mythology about the core,” says Stuart McGill, PhD, a highly regarded professor of spine biomechanics. “The idea has reached trainers & thru them, the public that the core means only the abs. There’s no science behind that idea.” The muscles forming the core must be balanced to allow the spine to bear large loads. If you concentrate on strengthening only one set of muscles within the core, you can destabilize the spine. The muscles forming the core must be balanced to allow the spine to bear large loads. If you concentrate on strengthening only one set of muscles within the core, you can destabilize the spine. “In our lab, the amount of load the spine can bear without injury was greatly reduced when subjects pulled in their belly buttons” during crunches & other exercises. Instead, he suggests, a core exercise program should emphasize all of the major muscles that girdle the spine – Abdominal Bracing - including the abs. Side bridge & “bird dog” exercise the important muscles embedded along the back & sides of the core. As for the abdominals, no sit-ups, McGill said; they place devastating loads on the disks. “Do not hollow your stomach or press your back against the floor,” McGill says. Gently lift your head & shoulders, hold briefly & relax back down. These 3 exercises – “the Big Three” - Bird Dog, Side Bridge, & Curl-Up can provide well-rounded, thorough core stability & avoid the pitfalls of the all-abs core routine. “I see too many people,” McGill said “who have six-pack abs and a ruined back.”

This article was borrowed from Dr Malik Slosberg research files.

Iliotibial Pain (ITB) Syndrome

Iliotibial Pain Syndrome (ITBS) is the most common cause of pain on the outside of the knee which is not due to problems within the knee itself (intra-articular). Effusion (swelling) around the front of the knee, clicking, a history of twisting injuries and postive stress tests may locate intrinsic problems. Furthermore there are a few less common problems which can arise within other structures of the knee itself.  However stresses within the ITB, the band of connective tissue which arises in the pelvis and extends down to below the knee presents an interesting problem.

The forces which arise in the hip and lateral knee are considerable. Walking alone produces stresses in and down the outside of the thigh which can be three times body weight so it's easy to see how jogging and running (particularly when introduced too rapidly) may contribute to compression problems.  In addition a history of lower back and pelvic pain or stiffness can compound the situation. Why?  The gluteal muscles alone (indeed any local group of muscles) are not strong enough to stop the hip collapsing on itself when we walk (let alone run). It is the co-ordinated action of muscles bound together by the inelastic connective tissues of the ITB which produce significant strength and stability and if they do not work in unison the region is left vulnerable to injury.

What of the lower limb?  Do poor foot mechanics cause alot of ITBS?  While this is possible the literature suggests that most problems arise in the pelvic region however the foot and ankle must be considered as possibilities in each individual case.


Douglas Scown

Which is the best neurology textbook?

http://www.amazon.com/Principles-Neural-Science-Edition-Kandel/dp/0071390111

Dr Kandell and collegues are known for research into human cognition but as they point out all behavior is an expression of or an output of the central nervous system. The human nervous system is based on trillions of reflexes joined by ever more complex interrelationships which although genetically determined change in response to it's own activity and the environment which it interprets.  The opening offers an intriguing insight into the scholarly history of the brain and it's most popular theories from the Egyptians to phrenology.  What's clear is that the last 50 years have seen gigantic advances in neuroscience, our understanding of behaviour and the irreducible marriage of the mind and body.  There is a brain and a body but the two fuse when we experience the world.

Doug Scown

What does an adjustment do?

Adjustment is the conglomerate term Chiropractors use to describe a set of modalities (treatment tools).  They vary enormously from so called 'low-force' techniques to the traditional HVLA adjustment (High Velocity Low Amplitude (short distance)).  In the hands of a clinician who is trained and experienced at knowing not just what but when and how to apply it these approaches can be very effective for various neuromusculoskeletal disorders.

Sometimes people will ask "what does it do".

Here's a list of some effects which have been observed during neuroscience research (courtesy of Matthew Long CDI)

• Engages mechanoreceptors to open mechanically gated ion channels and initiate a current flow into the largest and fastest primary afferent neurons.
• Uses a rapid lengthening of muscle to activate the dynamic components of the muscle spindle receptor to fire 1A afferents at a high frequency in order to modulate central neurology (greater than 200 Hz).  
• Alters the gain on the muscle spindle system to change muscle tone via the action of gamma motor neurons that innervate the intrafusal muscle fibres.
• Produces a ‘novel’ blend of sensory input that alters the state of the dorsal horn and shapes the responsiveness of spinal cord neurons to future inputs.
• Induces plastic changes in neural circuits via long-term potentiation and depression, depending upon the type of circuit i.e. manipulation can produce long-term depression of the projection neurons of the pain pathways.
• Alters the genetic responses in spinal cord neurons and those in the higher centres.
• Produces a propagated response in neurons in the ipsilateral cerebellum.
• Alters the frequency of firing of lower motor neurons to produce a change in muscle tone, joint stability, position and motion.

Doug Scown

PAIN is reliable in an unreliable way

The guys at The University of South Australia have put a great deal of work into the study of chronic pain.

Acute pain (as we might experience when we step on a nail or twist an ankle) is straight forward.  Do this - get that.  But what about pain which persists?  And what about pain which comes and goes or changes it's nature and location?  Confused?  Welcome to the world of chronic pain and the way it colours injury and dysfunction.

Health professionals still overwhelmingly deal with pain as if it were acute and something was damaged or broken.  Patients who present with continuing pain are told that their nerves are still healing or perhaps they have re injured the injury.  Is this accurate?

Chiropractors tend to see people with chronic or long term complaints.  Their problem often began yrs before but in the early stages their pain and dysfunction was brief and self limiting.  Furthermore it was aggravated by specific things, usually an awkward movement such as lifting and twisting.  Recently though the patient reports that their pain came from "nowhere".  "I slept wrong", "It just went out and now it's not going away".  In short their brief, self limiting problem has become chronic, 'unstable' and aggravated by trivial movements.  Additionally the pain has changed. It was sharper and "here".  Now it's sometimes sharp, often a dull ache or burning and it's spreading.  It feels like it could just "go" on me.

The patient has developed chronic pain.  The brain learns and changes through repetition and the repetition of pain can do interesting things with a plastic or moldable neurology.  Pain itself is a complex experience suffice to say it's important to pin down what originally triggered the problem (the disc, joint, bone, distortion - the diagnosis) and what may have led to it weakening (usually a combination of injury, sensation disturbance, lifestyle and of course genetics/epigenetics).

Ref   Apkarian et al. (2004) Chronic back pain