Hello, can you please help me understanding case7 question 5: the answer is D: visual dependence but not B: impaired use of vestibular system for balance?
When the patient was tested under mCTSIB condition 2 (eyes closed+ stable surface), he relies on vestibular system and somatosensory; when he was tested under condition 4 (eyes closed + unstable surface), he relies on vestibular system. To my understand if he lost balance with condition 2 and 4, that indicate impaired cues of vestibular system.
Thanks for this question! The common link between all of this patient’s losses of balance are an absence of visual cues (conditions 2 and 4). He does not have any losses of balance when visual cues are available (conditions 1 and 3). Therefore, we can safely conclude that he is visually dependent.
He may also have impaired use of vestibular cues, but we cannot say that with certainty given his loss of balance on condition 2 when he had somatosensory+vestibular cues available and did not lose his balance on condition 1 when somatosensory cues were also available.