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. 2024 Jan-Mar;17(1):100487.
doi: 10.1016/j.optom.2023.100487. Epub 2023 Oct 9.

Distance horizontal fusional facility (DFF): A new diagnostic vergence test for the acquired brain injury (ABI) population

Barry Tannen  1 , Emma Karlin  2 , Kenneth J Ciuffreda  3 , Noah Tannen  4 , John Shelley-Tremblay  5
Affiliations

Distance horizontal fusional facility (DFF): A new diagnostic vergence test for the acquired brain injury (ABI) population

Barry Tannen et al. J Optom. 2024 Jan-Mar.

Abstract

Purpose: To report the retrospectively-based, clinical diagnostic findings for the horizontal, distance, fusional facility (DFF) test in the non-TBI (traumatic brain inury), ABI (acquired brain injury) population.

Methods: The DFF test (4 pd base-out/2 pd base-in) was assessed and compared retrospectively in the first author's optometric practice in three clinical populations: (1) post-mTBI, visually-symptomatic (n = 52), (2) post-ABI, non-mTBI, visually-symptomatic (n = 34), and (3) visually-normal, visually asymptomatic (n = 44).

Results: The DFF values in each group were significantly different from each other (p < 0.05). The mean non-TBI, ABI group value was significantly lower than found in the mTBI group, and both were significantly lower than the mean found in the normal cohort (p < 0.05). There was a significant reduction in DFF with increased age (p < 0.001). ROC values for the AUC ranged from excellent to acceptable (0.94-0.74).

Conclusion: The DFF test is a new and useful way to assess horizontal, distance, dynamic, fusional facility in those with presumed non-mTBI, ABI neurological conditions to assist in its diagnosis.

Keywords: Acquired brain injury; Diagnosis; Distance horizontal fusional facility (DFF); Neuro-optometry; Vergence.

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Conflict of interest statement

Conflicts of interest Dr. Barry Tannen has a financial interest in the Tannen Flipper Test.

Figures

Fig 1
Fig. 1
The TFT flippers.
Fig 2
Fig. 2
TFT for all three populations using a density plot where the width represents the estimated frequency. Black square is the median. Upper and lower parts of grey box are the first and third quartiles. Individual subject data points are in grey circles.
See this image and copyright information in PMC

References

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