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What the latest evidence says about Brock String therapy, convergence insufficiency, and spasm of the near reflex

A lot of us have been taught convergence exercises such as Brock String and pencil push-ups at courses related to concussion and vestibular rehabilitation.

Recently, however, concerns have emerged suggesting these exercises may worsen visual dysfunction or even cause permanent damage.

Given this, I thought it would be prudent to revisit the literature and see what the evidence actually says.

The short answer?

Current evidence does not support permanent structural visual or neurological harm from convergence exercises.

In fact, the newest concussion-specific research suggest...

Most clinicians are comfortable treating classic posterior canal BPPV.

Most of us were taught and continue to be taught that sustained apogeotropic nystagmus indicates cupulolithiasis when the lateral canal is involved.

But what if that’s not necessarily true?

In this blog I want to take you on a brief journey and challenge what we’ve traditionally been taught about these presentations. 

Understanding Horizontal Canal BPPV

I think that we can all agree that when positional testing (i.e. Supine Roll, Dix-Hallpike, Sidelying, Bow & Lean) produces horizontal nystagmus, we are most often dealing with horizontal canal BPPV. It’s important to remember that positional nystagmus can also be seen with conditions such as light cupula or central causes.

The classic p...

Many vestibular clinicians capture eye movements routinely,  but what if your infrared goggles were revealing clues about autonomic nervous system function, not just nystagmus?

A chiropractor friend of mine recently sent me a recording of a patient with atypical positional nystagmus, one of those cases where the eye movements do not follow the usual “BPPV patterns.” We worked through the positional findings and landed on a reasonable clinical interpretation and plan.

My friend who shared the recording is an exceptionally sharp clinician, currently working on his PhD, with deep expertise in the autonomic nervous system. What really caught my attention was his notes stating:

Cranial Nerve...

Lateral canal light cupula can closely mimic lateral canal BPPV, yet it often fails to respond to canalith repositioning or liberatory maneuvers. This case study explores diagnostic features, migraine susceptibility, and clinical reasoning that supports conservative management and an excellent prognosis.

Understanding Light Cupula in the Lateral Canal

Benign paroxysmal positional vertigo (BPPV) is commonly conceptualized as a mechanical disorder driven by free-floating otoconia. In most cases, canalith repositioning maneuvers are highly effective. However, not all gravity-dependent positional nystagmus reflects classic canalithiasis.

Light cupula of the lateral canal represents a cupula-d...

 Have you ever seen a patient with acute dizziness and wondered whether it could be a stroke? You’re not alone. Distinguishing between a central cause such as a posterior circulation stroke and a peripheral cause like vestibular neuritis can be challenging, especially in the emergency setting.

That’s where the HINTS plus test comes in. This powerful bedside tool helps clinicians determine whether acute dizziness is due to a stroke or a vestibular disorder and it’s been shown to outperform early MRI when used correctly.

In this post, we’ll outline what the HINTS plus test is, how to perform each step, how to interpret the findings, and when to use it in practice.

What Is the HINTS Plus Tes...

Most of us do not think about the vestibular system until something goes wrong. Yet this hidden sensory system works constantly in the background, keeping us upright, stabilizing our vision when we move our head, and even helping regulate blood pressure when we change posture. However, when vestibular input is impaired, the consequences can be profound: dizziness, disorientation, blurred vision, or even catastrophic accidents in aviation and spaceflight.

Understanding the vestibular system and spatial disorientation not only improves clinical care, but also explains why pilots crash, why astronauts get sick, and why patients describe feeling like they do.

The Vestibular System and Its Role...

Why Pediatric Vestibular Assessment Matters

Pediatric vestibular assessment is an often-overlooked area in clinical practice. Yet research shows that nearly 50% of children with hearing loss have some degree of vestibular dysfunction (Cushing et al., 2013; Verbecque et al., 2017). Risk is higher in children with:

• Severe hearing loss (>66 dB)

• Structural inner ear anomalies (e.g., enlarged vestibular aqueduct)

• Congenital cytomegalovirus

• Usher syndrome type 1

• Meningitis or temporal bone fracture

• Ototoxic medication exposure

Undetected vestibular loss in children can lead to gross motor delays, poor postural control, academic challenges, and limited partici...

At North 49, I’ve been incredibly fortunate to learn from many brilliant clinicians throughout my career and I see it as part of my responsibility to share what I’ve learned along the way. My goal is that these blogs are a means of reviewing what I have learned and assist in supporting your journey by offering practical, evidence-based insights.

This blog, however, is a little different.

It’s a summary of a doctoral project by someone I’ve had the honour of working with for several years: Nycole Pataki. Nycole recently relocated from Saskatchewan to Arizona with her family and asked if I’d read her doctoral project. After doing so, I knew this work deserved a broader audience. With her per...

Whether you’re helping a professional athlete, a weekend warrior, an injured worker, or a senior who slipped at home, concussion management is part of your everyday clinical practice. If you’ve been in the field for a while, you’ve seen firsthand how much things have evolved.

Thirty years ago, we relied on grading systems like the Cantu Classification, Colorado Medical Society Guidelines, and AAN Guidelines. These were based largely on loss of consciousness and symptom duration, criteria we now know don’t reliably predict outcomes. Thankfully, modern concussion guidelines for healthcare providers are more evidence-informed and patient-specific.

In this blog, we’ll review three key resou...