The subclinical stage of any entity is considered to be a presentation that escapes the more commonly applied clinical tests. Of course this is accentuated when not looking for something, as the famous clinical dictum reminds us: we miss more by not looking than by not seeing. A brief piece in the Australian Journal of General Practitioners last year suggested that a tilt in perspective is sometimes needed when looking at the significance of ocular torticollis.
The article cites a case of long-standing superior oblique palsy in a 95 year-old patient, and reviews application of the Parks-Bielschowsky Three Step Method to isolate paretic muscles, yet notes this this test only has a sensitivity of 70%. This lack of sensitivity, owing to the spread of comitance over time, makes the detection of subtle ocular postural skews more challenging. As the article notes, the treatment of choice in some of these instances may be “refractory prisms”. We blogged about this a few years ago regarding a more sensitive sensory variant of the Three Step Test, and more recently reviewed the art of prescribing prism, particularly for subtle imbalances with vertical vectors.
Whenever you see a child with a subtle head tilt in a consistent direction, it is prudent to assume that there is a vertical or cyclovertical imbalance until proven otherwise. The easiest way to confirm that in free space is to use a red maddox rod/Risley prism together with a fixation light.
With the zero line perfectly perpendicular to the nose, when the head is positioned to eliminate the habitual heat tilt, the patient will observe that the line is slanted. The degrees of torque that you need to angle the Maddox rod before the slant is neutralized gives you a feel for the amount of cyclophoria. While this can be done a trial frame with a loose Maddox rod from your trial set so that the exact number of degrees can be measured, I prefer to do it this way in free space for several reasons. One is that the trial frame is clunky and makes controlling head position more difficult, particularly with younger children. Another is that it makes it easier to measure the amount of residual vertical phoria in conjunction when the cyclorotation is neutralized, and vice-versa. Whenever there is a subtle, but clinically significant vertical or cyclovertical imbalance, go back into the history and ask about the parent’s recollection of torticollis being present in infancy. Due to the spotlight that OTs and PTs place on this in early intervention, parents often recollect this. While that won’t likely influence what you prescribe, it can provide a clue about underlying etiology.
The clinical report that I cited above from the Australian Journal of General Practice provided reference to an interesting review on torticollis from the Journal of Child Neurology. It notes that torticollis can be seen at all ages, from newborns to adults, and can be congenital or postnatally acquired. Congenital primary torticollis usually occurs when there is breech presentation, or trauma during birth, impacting the sternocleidomastoid muscle. Acquired torticollis usually occurs as a result of trauma. This is an entity to bear in mind when there is a history of mTBI, and added to the list of subtle but clinically significant conditions that might otherwise escape detection.
The review in the Journal of Child Neurology by Tomczak and Rosman offers a new classification of torticollis based on dynamic qualities and pathogenesis. Torticollis can be classified as either nonparoxysmal (nondynamic) or paroxysmal (dynamic). Ocular torticollis, in which the head tilt and chin or face turn is due primarily to EOM or visual imbalance, and secondarily to adaptive sternocleidomastoid contracture, is classified as nonparoxysmal. An example of paroxysmal would be primary cervical misalignment contributing secondarily to ocular adaptations involving a vertical or cyclovertical vector. The term paroxysmal may be familiar to you from the condition of BPPV, or Benign Paroxysmal Postional Vertigo. Particularly fascinating is that included in Tomczak and Rosman’s classification of paroxysmal torticollis is an etiology of conversion disorder.
To finish on a lighter note, not all head tilts signify primary or secondary ocular torticollis. In some cases a head tilt is adopted consciously or subconsciously without a functional adaptive purpose. But don’t take my word for it. Readers of Best Life Online learn that tilting the head comes in at #22 on the list of 23 subtle ways to make yourself more attractive. And #23 on the list? …. Smile more 🙂