Examination of Cranial nerves - Pediatrics

cranial nerve examination of paediatric age group

1. Examination of cranial nerves Praveen rk No: 75

2. Cranial nerves I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducent VII Facial VIII Vestibulocochlear IX Glossopharyngeal X Vagus XI Accessory XII Hypoglossal

3. The olfactory, optic and vestibulocochlear nerves are entirely sensory The occulomotor , trochlear, abducent , accessory and hypoglossal nerves are entirely motor The remaining nerves are mixed nerves.

4. 1. Olfactory nerve Function – sense of smell Test each nostril separately with other nostril and eye closed. Use familiar materials like orange peel, coffee powder, soap, toothpaste, asafoetida , etc. For infants and retarded children note the behavioral response

5. 11. Optic nerve Function – vision Components of examination - Acuity of vision Field of vision Color vision Fundus examination

6. Visual acuity Above 3 years – vision screened by use of E chart or Snellens picture charts Visual acuity recorded according to formula V=d/D, where d is distance at which patient can read the letter and D is the distance at which letters are readable by a person with normal vision. In infants – vision tested by checking blinking response to bright light, turning of head towards diffuse light or following red moving ball or ring Visual acuity in a term newborn baby is 6/45, 6/18 at one year, 6/6 at 6to7 years.

7. Visual field C onfrontation test in older children, and in younger children by moving a light/toy Confrontation test- examiner sits one meter away facing the patient whose right eye is tested with examiners left eye and vice versa. The other eye is kept covered self b y the corresponding hands of the examiner and the patient. Differing numbers of fingers of examiner are presented in different quadrants of visual field from extreme periphery. Child is asked to mimic the number of fingers in each field as soon as it is seen

8. For small children move a light or red ball into the visual field from behind forwards and observe the response Visual induced refixation - infant’s attention is directed elsewhere while the examiner flashes light in various field of vision. Normal response is the infant turning and looking to light

9. Color vision Test whether child is able to appreciate 3 primary colors- red, green, blue by showing toys Ishihara pseudoisochromatic eye plates are used in older children. Child is asked to identify the number produced by virtue of different colors.

10. Pupil examination Size, shape and pupillary reflexes Test – patient should be looking into distance. Bring the light beam directed to pupil from periphery. Sudden constriction of pupil occurs (direct response). Repeat the test , this time looking at the contralateral pupil, which will normally constrict (consensual response) Accomodation reaction – hold up a pen close to patients nose. Ask patient to look away and then quickly at the pen. As eyes converge, pupils constrict.

11. 111.occulomotor, 1v.trochlear, v1.abducent nerves Function – eye movements Diplopia is the most reliable symptom of its involvement Test – observe the eye movements when a colored object is moved in various directions of visual field. Above age of 4 years child is asked to look at a red pen as it is moved in direction of action of extraocular muscles Doll’s eye movement phenomenon is used to test ocular movements in infants

12. Extraocular muscles 4 Recti and 2 Obliques Superior rectus Inferior rectus Medial rectus Lateral rectus Superior oblique Inferior oblique

13. Squint ‐ paralytic ‐range of eye movements impaired, diplopia present and is sudden in onset. ‐ nonparalytic /concomitant – range of eye movements normal

14. v. Trigeminal nerve Function – sensory to face and eyes, motor to muscles of mastication Corneal and conjunctival reflex Sensory ‐test sensations over forehead, cheeks and chin ( ophthalmic, maxillary and mandibular divisions) Motor ‐ ask to clench the teeth and palpate over the cheek and temple (masseters & temporalis ) ‐ ask to open the mouth wide ‐ jaw deviates to the paralyzed side (pterygoid )

15. Vii. Facial nerve Function – Motor to facial muscles, Taste sensation to anterior 2/3 of tongue Motor ‐ raise the eyebrows (frontalis) –wrinkling ‐ try to open tightly closed eyes ( orbicularis oculi ) ‐ obliteration of nasolabial fold on paralyzed side ‐ look for deviation of angle of mouth ‐ blowing of air ( buccinators ) Sensory ‐ test for taste in the anterior 2/3 rd of tongue

16. Lower motor neuron lesion of 7th nerve results in complete lack of ipsilateral facial movements Upper motor neuron lesion – only lower half of the face is affected (upper part of the face has bilateral cortical innervation )

17. viii. Vestibulocochlear nerve Function – sound perception and maintenance of body balance Hearing assessment Ask for tinnitus Rinne’s test Weber ‘s test Audiometry from 3 yrs onwards In infants – assess for blinking of eyes, sudden change or cessation of activity, change in heart rate, turning of head towards the sound stimulus of a bell, whistle, etc

18. Vestibular nerve Vertigo, giddiness and dizziness – complaints Caloric test – child’s head is kept in semireclining position. 10 ml cold water (30 o C) or warm water (44 o C) is injected into ear canal and nystagmus recorded on electromyography. Cold caloric test produce slow deviation of eye towards side of injection and opposite effect in hot caloric test. No nystagmus occur in case of vestibular damage.

19. IX & X ‐ GLOSSOPHARYNGEAL AND VAGUS NERVE Function – IXth : motor for stylopharyngeus muscle and middle pharyngeal sphinctor , sensory to posterior 1/3 of tongue Xth : Motor for soft palate,pharynx,larynx , sensory and motor for respiraory passage, heart and most of abdominal viscera Nasal regurgitation of fluids and nasal twang of voice Position of uvula moves to normal side in Xth nerve palsy

20. Palatal movement - no movement on the affected side ; pulled to normal side - palate immobile if bilateral palatal palsy Gag reflex – tickle the posterior pharyngeal wall and look for contraction of pharynx‐afferent is IX and efferent is X Sensory – taste in posterior 1/3 of tongue

21. XI. ACCESSORY nerve Trapezius muscle ‐ Tested by shoulder shrugging against resistance ‐ Drooping of shoulder on paralyzed side and scapula drop to lower level Sternomastoid ‐ ask the child to turn his head to one side or other against resistance

22. X11. hypoglossal nerve Ask the child to protrude the tongue‐ it deviates to the paralyzed side Fasciculation of tongue in Wernig –Hoffman disease Atrophy of tongue on affected side in LMN palsy In UMN palsy ,tongue is spastic , thin and pointed

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