Abnormal Eye Movements in Spinocerebellar Ataxia Type 3
Background: Abnormal eye movements are common in spinocerebellar ataxias Type 3 (SCA3). We conducted the research to explore the frequency of abnormal eye movements in Chinese patients with SCA3, to compare the demographic and clinical characteristics between SCA3 patients with and without each type of abnormal eye movement, and to explore the correlation between abnormal eye movements and the severity of ataxia.
Methods: Seventy-four patients with SCA3 were enrolled in this cross-sectional study. Six types of abnormal eye movements including impaired smooth pursuit, increased square-wave jerks (SWJ), gaze-evoked nystagmus (GEN), slowing of saccades, saccadic hypo/hypermetria and supranuclear gaze palsy were evaluated by experienced neurologists. The severity of ataxia was evaluated by Scale for the Assessment and Rating of Ataxia (SARA).
Results: The prevalence of impaired smooth pursuit, increased SWJ, GEN, slowing of saccades, saccadic hypo/hypermetria and supranuclear gaze palsy in Chinese SCA3 patients was 28.4%, 13.5%, 78.4%, 41.9%, 23.0%, and 5.4%, respectively. SCA3 patients with GEN had higher scores of International Cooperative Ataxia Rating Scale (ICARS-IV) and total ICARS, and longer length of CAG repeat than patients without GEN. SCA3 patients with slowing of saccades had a longer disease duration, higher scores of ICARS-I, ICARS-II, total ICARS and SARA than patients without slowing of saccades. SCA3 patients with saccadic hypo/hypermetria had higher scores of ICARS-III, ICARS-IV, and SARA than patients without saccadic hypo/hypermetria. The demographic and clinical characteristics did not differ significantly between SCA3 patients with and without impaired smooth pursuit, increased SWJ, or supranuclear gaze palsy. Multivariate linear regression showed that the number of abnormal eye movements (0-6), disease duration, Hamilton Depression Rating Scale-24 (HDRS-24) score, and CAG repeat length were positively correlated with SARA score, whereas Montreal Cognitive Assessment (MoCA) score was negatively correlated with SARA score in SCA3.
Conclusions: An increased number of abnormal eye movement types correlated with the severity of ataxia in SCA3.
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This is a list of supplementary files associated with this preprint. Click to download.
Segment 1. This patient demonstrates impaired smooth pursuit; Segment 2. This patient demonstrates increased square-wave jerks; Segment 3. This patient demonstrates gaze-evoked nystagmus; Segment 4. This patient demonstrates slowing of saccades; Segment 5. This patient demonstrates saccadic dysmetria; Segment 6. This patient demonstrates vertical supranuclear gaze palsy.
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Abnormal Eye Movements in Spinocerebellar Ataxia Type 3
Posted 12 Jan, 2021
On 12 Jan, 2021
Posted 03 Jan, 2021
On 03 Jan, 2021
On 01 Jan, 2021
On 01 Jan, 2021
On 01 Jan, 2021
Received 22 Nov, 2020
On 22 Nov, 2020
Received 22 Nov, 2020
Invitations sent on 10 Nov, 2020
On 10 Nov, 2020
On 09 Nov, 2020
On 09 Nov, 2020
On 09 Nov, 2020
On 12 Oct, 2020
Received 11 Oct, 2020
Received 27 Sep, 2020
On 26 Sep, 2020
On 18 Sep, 2020
Invitations sent on 13 Sep, 2020
On 07 Sep, 2020
On 06 Sep, 2020
On 06 Sep, 2020
On 05 Sep, 2020
Background: Abnormal eye movements are common in spinocerebellar ataxias Type 3 (SCA3). We conducted the research to explore the frequency of abnormal eye movements in Chinese patients with SCA3, to compare the demographic and clinical characteristics between SCA3 patients with and without each type of abnormal eye movement, and to explore the correlation between abnormal eye movements and the severity of ataxia.
Methods: Seventy-four patients with SCA3 were enrolled in this cross-sectional study. Six types of abnormal eye movements including impaired smooth pursuit, increased square-wave jerks (SWJ), gaze-evoked nystagmus (GEN), slowing of saccades, saccadic hypo/hypermetria and supranuclear gaze palsy were evaluated by experienced neurologists. The severity of ataxia was evaluated by Scale for the Assessment and Rating of Ataxia (SARA).
Results: The prevalence of impaired smooth pursuit, increased SWJ, GEN, slowing of saccades, saccadic hypo/hypermetria and supranuclear gaze palsy in Chinese SCA3 patients was 28.4%, 13.5%, 78.4%, 41.9%, 23.0%, and 5.4%, respectively. SCA3 patients with GEN had higher scores of International Cooperative Ataxia Rating Scale (ICARS-IV) and total ICARS, and longer length of CAG repeat than patients without GEN. SCA3 patients with slowing of saccades had a longer disease duration, higher scores of ICARS-I, ICARS-II, total ICARS and SARA than patients without slowing of saccades. SCA3 patients with saccadic hypo/hypermetria had higher scores of ICARS-III, ICARS-IV, and SARA than patients without saccadic hypo/hypermetria. The demographic and clinical characteristics did not differ significantly between SCA3 patients with and without impaired smooth pursuit, increased SWJ, or supranuclear gaze palsy. Multivariate linear regression showed that the number of abnormal eye movements (0-6), disease duration, Hamilton Depression Rating Scale-24 (HDRS-24) score, and CAG repeat length were positively correlated with SARA score, whereas Montreal Cognitive Assessment (MoCA) score was negatively correlated with SARA score in SCA3.
Conclusions: An increased number of abnormal eye movement types correlated with the severity of ataxia in SCA3.
Figure 1
Figure 2
Figure 3