Clinical characteristics of the patients with downbeat nystagmus (DBN), categorised by gender, age, neuro-ophthalmological findings, MRI findings, aetiology of downbeat nystagmus, disease duration since diagnosis and response to treatment
| Subj. | Age, sex | Sequence of treatment | Aetiology of DBN | Duration of DBN | MRI findings | Neuro-ophthalmological findings (apart from DBN) | Response* (%) |
|---|---|---|---|---|---|---|---|
| 1 | 70, m | 4-AP—placebo | Idiopathic | 16 | Normal | 3, 6 | −152.91 |
| 2 | 76, f | 4-AP—placebo | Idiopathic | 10 | Normal | 1, 2, 3, left gaze hypermetric saccades | |
| 3 | 69, m | Placebo—4-AP | Secondary (degeneration) | 4 | Cerebellar atrophy | 1, 2, 4, 3 | |
| 4 | 65, m | 4-AP—placebo | Idiopathic | 2 | Normal | 1, 2, 3, 6 | 48.06 |
| 5 | 78, f | 4-AP—placebo | Idiopathic | 8 | Relatively small flocculus | 1, 2, 3, 5, 6, horizontal hypermetric saccades | 115.92 |
| 6 | 48, m | 4-AP—placebo | Secondary (degeneration) | 13 | Cerebellar atrophy | 2, 5 | −14.60 |
| 7 | 62, m | 4-AP—placebo | Idiopathic | 1 | Normal | 1, 2, 3, 6 | −8.13 |
| 8 | 67, m | 4-AP—placebo | Idiopathic | 2 | Normal | 1, 3 | 165.87 |
| 9 | 69, m | Placebo—4 AP | Idiopathic | 1 | Normal | 2, 3 | 5.00 |
| 10 | 62, f | 4-AP—placebo | Idiopathic | 4 | Normal | None | 177.08 |
| 11 | 60, f | Placebo—4-AP | Idiopathic | 12 | Normal | 2, 3, 5, 6 | 11.73 |
| 12 | 71, f | Placebo—4-AP | Idiopathic | 5 | Normal | 2, 3, 6 | 34.10 |
| 13 | 70, m | Placebo—4-AP | Idiopathic | 11 | Normal | 2, 3, 6 | −73.35 |
| 14 | 77, m | 4-AP—placebo | Idiopathic | 2 | Normal | 1, 2, 3, 4, 5 | −57.19 |
| 15 | 65, m | 4-AP—placebo | Idiopathic | 3 | Moderate cerebral atrophy | 3 | |
| 16 | 75, f | Placebo—4 AP | Idiopathic | 5 | White matter lesions bilaterally and in central pons | 2, 3, hypometric and slowed saccades | −64.62 |
| 17 | 71, m | 4-AP—placebo | Secondary (SCA-6) | 5 | Normal | 5, slowed saccades | −79.87 |
| 18 | 62, m | Placebo—4 AP | Idiopathic | 9 | Not possible | 1, 3, hypoactive optokinetic eye movement | 379.00 |
| 19 | 70, f | 4-AP—placebo | Idiopathic | 26 | Marked atrophy of medial temporal lobe | 3 | |
| 20 | 42, f | Placebo—4-AP | Idiopathic | 9 | Normal | UBN on upward gaze | −4.04 |
| 21 | 66, m | Placebo—4-AP | Idiopathic | 40 | Normal | 2, 5 | 33.06 |
| 22 | 23, f | Placebo—4-AP | Secondary (degeneration) | 4 | Diffuse cerebral, medullar and cerebellar atrophy | 2, 5 | 19.99 |
| 23 | 74, f | 4-AP—placebo | Idiopathic | 16 | Normal | 5, 6 | 90.30 |
| 24 | 74, f | 4-AP—placebo | Idiopathic | 5,5 | Normal | 1, 3, 5, 6, alternating skew deviation during lateral gaze, gaze holding deficit horizontally and downward | 28.37 |
| 25 | 51, m | Placebo—4-AP | Secondary (paraneoplastic) | 3 | High signals in periphery of cerebellum bilaterally | None | −73.71 |
| 26 | 63, m | Placebo—4-AP | Idiopathic | 5 | No path around foramen magnum, T2 hyperintensity in pons | None | 26.88 |
| 27 | 71, m | 4-AP—placebo | Secondary (degeneration) | 7,5 | Various lesions due to multiple sclerosis | Occasionally dysmetric saccades | −98.60 |
With regard to the response, positive values indicate a better response(*) under 4-AP than under placebo.
Values were calculated as follows: percentage of change of slow phase velocity (SPV) from baseline to the measurement 60 min after first drug administration for 4-AP and placebo. Afterwards, subtraction of the percentage of change of SPV under placebo from the percentage of change of SPV under 4-AP. 1=pathological head thrust test; 2=gaze-evoked nystagmus; 3=saccadic smooth pursuit; 4=rebound nystagmus; 5=VOR suppression disturbed; 6=upward vertical OKN not inducible/diminished.
OKN, optokinetic nystagmus; UBN, upbeat nystagmus; VOR, vestibulo-ocular reflex.