Examination of the balance system
In addition to the vestibule, proprioception (cerebellum) and vision are also involved in balance - that's why balance disorders are difficult to assess.
Spontaneous and provoked vestibular phenomena[edit | edit source]
They are objective.
Nystagmus[edit | edit source]
Nystagmus are rhythmic movements of the bulbs in a certain plane and direction with a fast and slow component:
- the slow component is the response to vestibular stimulation,
- the fast component is compensation from the CNS,
- direction of nystagmus – given according to the fast component – rightward, leftward, up, down,
- planes of nystagmus – horizontal, vertical, rotatory and diagonal.
- Intensity of nystagmus – 3 degrees:
- Grade I – nystagmus occurs when looking to one side, to which it then points,
- II. degree - it can also be observed when viewed directly,
- III. degree - it can also be observed when looking at the opposite side to the direction of the nystagmus.
- we further evaluate – frequency, amplitude and angular velocity,
- positional nystagmus – can be provoked by slowly moving the head into a certain position,
- positioning nystagmus – provoked by rapid change of position, onset with latency,
- vertical, diagonal, rotary or multidirectional is always central.
Standing according to Romberg[edit | edit source]
- lie down, eyes closed.
- head first straight, then with a turn to both sides.
- the affected person leans or falls in the direction of the slow component of the nystagmus (behind the diseased ear).
- we can scan optically and evaluate with posturography.
Deviations of the arms according to Hautant[edit | edit source]
- forearm, close eyes, watch for half a minute,
- in a peripheral disorder, both hands deviate in the direction of the slow component of the nystagmus.
Experimental examination of the vestibular system[edit | edit source]
- in experiments we imitate the irritation or attenuation of the apparatus,
- we mainly monitor nystagmus, but we can also monitor Romberg and Hautant.
Caloric examination[edit | edit source]
- the patient is lying down, the head is tilted forward by 30° (verticalize the lateral semicircular canal),
- through the glasses we watch the eyes,
- we use water at 30 °C and 44 °C (ie ± 7 °C from body temperature),
- first we examine both ears gradually (first one, then the other) with cold and then both with warm water,
- on the stopwatch, we measure the latency to the onset of nystagmus,
- cold water into the ear canal dampens (heat strengthens) the response of the lateral semicircular canal,
- we induce 2 nystagmus – one in the contralateral direction (extinction) and the other in the homolateral direction (irritation),
- nystagmus occurs in this way even in a healthy person.
- Evaluation of results
- bilateral hyporeflexia – the duration of nystagmus is below the physical value.
- bilateral hyperreflexia – the duration of nystagmus is above the physical value.
- lateral difference in excitability – difference in times, pathological reduction in excitability of one side.
- directional dominance – the difference in the size of the deviation, the sum of the values in one direction is noticeably higher than in the other.
- vestibular areflexia – does not cause nystagmus.
Investigation of rotations[edit | edit source]
- we stimulate both labyrinths at the same time, on a swivel chair, head tilted forward 30°, eyes closed,
- we rotate 1 revolution in 6 s, stop suddenly and read the nystagmus,
- physiologically, nystagmus lasts 25–60s, against the direction of rotation.
Examination of the fistula symptom[edit | edit source]
- in the presence of a labyrinthine fistula (it is most often in the semicircular canal),
- blow the balloon into the ear, increase the pressure and if there is a whistle, nystagmus will occur.
Links[edit | edit source]
Related Articles[edit | edit source]
Source[edit | edit source]
- BENEŠ, Jiří. Studijní materiály [online]. ©2007. [cit. 2009]. <http://jirben2.chytrak.cz/materialy/orl_jb.doc>.