AHP

Question 1

What is the definition of a normal head posture?

Answer 1

The median plane of the head is continuous with the median plane of the body

Question 2

What is Torticollis?

Answer 2

AHP including a head tilt

Question 3

What are some non-ocular congenital AHPs?

Answer 3

Contracture of sternocleidomastoid muscle in neck

Question 4

What are some non-ocular acquired AHPs?

Answer 4

• Deafness - unilateral/ asymmetrical
  Head turn to more affected side
• Shyness
  Often head down (chin depression) and variable
• Habit
• Neurological – brain tumour
• Arthritis / rheumatism
• Disorders/ injuries of spine

Question 5

What ocular reasons do people have for having an AHP?

Answer 5

Obtain/ maintain BSV
- Incomitant strabismus
- A & V patterns

Separate diplopic images further
- Insuperable diplopia

Gain foveal fixation
- Infantile esotropia
- Gross limitation preventing foveal fixation in PP

Optimise VA
- Refractive errors
- Nystagmus

DVD
- Head tilt towards fixing eye appears to ↓ DVD

Centralise field of vision
- Bilateral ptosis
- Gaze palsies
- Homonymous hemianopia

Avoid pain
- Graves Orbitopathy
- Blow-out #

Question 6

Why might be consider under-correction in surgery of an AHP?

Answer 6

Patients with a marked AHP such as a head tilt due to SO palsy, you may consider under-correction as patient is unlikely to resume normal head posture

Question 7

LIR Palsy AHP?

Answer 7

Head Tilt Right (tilt to HypoT)
Head Turn Left
Head Down

Question 8

How do we assess AHP?

Answer 8

• Ensure patient sitting / standing straight
• Observe patient on same level, directly in front
• Note any facial asymmetry
• Assess if one ear more visible than other
• Check eyes are level
• Observe chin position from side
• Straighten head and allow patient to resume “normal” position
• Observe AHP for 1/3m, 6m, when performing visual task
• Old photos may identify duration of AHP
• Ask patient if aware of AHP

Question 9

What’s the difference between congenital non-ocular and ocular AHP on the following:
- Straightening head
- Ocular symptoms
- Awareness of AHP
- Presence of BSV
- CT
- OM
- Hess
- Occlusion of one eye
- Uniocular VA testing
- Medical

Answer 9

• Straightening head
  N.O. - Difficult
  O - Easy
• Ocular symptoms
  N.O - usually asymptomatic
  O - may be symptomatic
• Awareness of AHP
  N.O - May be
  O - Often unaware longstanding, aware + c/o neck ache - acquired
• Presence of BSV
  N.O - BSV c/s AHP
  O - BSV c/AHP or s/AHP c/o diplopia/suppress
• CT
  N.O - NAD
  O - Presence of strabismus / nystagmus
• OM
  N.O - Full
  O - Muscle imbalance
• Hess
  N.O. - Normal
  O - Muscle imbalance
• Occlusion of one eye
  N.O - No change of AHP
  O - Head straightening on occlusion of paretic eye
• Uniocular VA testing
  N.O. - No change of AHP
  O - May change to improve VA if presence of nystagmus
• Medical
  N.O - Indications for reasons adopting AHP example deafness
  O - May c/o illness relevant to muscle imbalance

Question 10

Management of AHP for:
Symptomatic - Small/Moderate AHP
Symptomatic - Marked AHP

Answer 10

Small-moderate AHP
- Relieve using prisms, occlusion
- Botulinum toxin injection
- Surgery

Marked AHP
- Indication for surgery
Neurogenic palsies
Mechanical restrictions of OM
Nystagmus
Young children- prevent secondary contractual neck changes
- Affect amount of surgery
Consider under-correct if longstanding

Question 11

What is the purpose of a head turn?

Answer 11

• Move eyes away from field of action of paresed muscle
• Move eyes to a position where deviation is least
• Enable eye to fixate centrally – gross limitation
• Permit the use of the nose as an occluder

Question 12

Which side is a head tilt always towards?

Answer 12

Head tilt always towards side of hypotropic eye

Superior muscles (SR & SO) tilt and turn same way

Inferior muscles (IR & IO) tilt and turn opposite ways

Question 13

How can we measure head posture in clinic?

Answer 13

Often an estimate – slight, moderate, marked
- Photographs
- Goniometer
- Cervical range of motion (CROM) instrument: designed to assess the range of motion in the cervical spine

Use of technology to measure head posture
- The Cambridge Face tracker
iPhone compass function
- May be possible to use but require further research

The Cambridge Face Tracker uses neural networks (constrained local neural fields) to recognize facial features in video.
It allows useful quantification of head posture in real time or from precaptured video. Its performance is similar to the CROM device

Question 14

Look at questions and answers for head postures on slides