The effects of afferent stimulation on congenital nystagmus foveation periods

• Published in: Vision research (Oxford) Vol. 35; no. 16; pp. 2371 - 2382
• Main Authors: Sheth, N.V., Dell'osso, L.F., Leigh, R.J., Van Doren, C.L., Peckman, H.P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.1995; Elsevier Science
• Subjects: Acuity; Adolescent; Adult; Biological and medical sciences; Child; Congenital nystagmus; Electric Stimulation; Female; formula omitted; Fovea Centralis - physiology; Humans; Male; Mathematics; Medical sciences; Middle Aged; Neurons, Afferent - physiology; Nystagmus, Pathologic - congenital; Nystagmus, Pathologic - physiopathology; Oculomotor disorders; Ophthalmology; Physical Stimulation; Time Factors; Vibration; Visual Acuity - physiology; Somatosensory simulation Foveation; Congenital nystagmus; Acuity; Human; Congenital; Electrical stimulus; Visual acuity; Macula; Eye disease; Improvement; Trigeminal nerve; Vision; Nystagmus; Cranial nerve; Perception; Sensorimotor nerve; Neck; Mechanical stimulus; Oculomotor syndrome
• ISSN: 0042-6989; 1878-5646
• DOI: 10.1016/0042-6989(94)00321-C

Visual acuity in congenital nystagmus (CN) patients is related primarily to the duration of “foveation periods”, during which the image of the target is relatively stationary in the foveal area. Thirteen individuals with CN were studied to test the hypothesis that somatosensory stimulation (vibration or electrical) of either the forehead or the neck damps CN and improves visual acuity. We identified characteristics of the nystagmus waveform that were likely to be important in determining visual acuity and combined these measures into an “acuity function” (NAFP) that correlated well with visual acuity ( r 2 = 0.91). Statistically significant changes in NAFP were used to assess the effects of afferent stimulation; positive effects were found in nine subjects. Vibratory stimulation (especially on the neck) was found to be more effective than electrical stimulation. CN amplitude reduction alone was neither necessary nor sufficient to improve acuity. Foveation duration was the single most important factor determining acuity. Based on our findings, afferent stimulation should be considered as an alternative or additional treatment to improve visual acuity in CN patients.