Automating the analysis of eye movement for different neurodegenerative disorders

The clinical observation and assessment of extra-ocular movements is common practice in assessing neurodegenerative disorders but remains observer-dependent. In the present study, we propose an algorithm that can automatically identify saccades, fixation, smooth pursuit, and blinks using a non-invasive eye tracker. Subsequently, response-to-stimuli-derived interpretable features were elicited that objectively and quantitatively assess patient behaviors. The cohort analysis encompasses persons with mild cognitive impairment (MCI), Alzheimer's disease (AD), Parkinson's disease (PD), Parkinson's disease mimics (PDM), and controls (CTRL). Overall, results suggested that the AD/MCI and PD groups had significantly different saccade and pursuit characteristics compared to CTRL when the target moved faster or covered a larger visual angle during smooth pursuit. These two groups also displayed more omitted antisaccades and longer average antisaccade latency than CTRL. When reading a text passage silently, people with AD/MCI had more fixations. During visual exploration, people with PD demonstrated a more variable saccade duration than other groups. In the prosaccade task, the PD group showed a significantly smaller average hypometria gain and accuracy, with the most statistical significance and highest AUC scores of features studied. The minimum saccade gain was a PD-specific feature different from CTRL and PDM. These features, as oculographic biomarkers, can be potentially leveraged in distinguishing different types of NDs, yielding more objective and precise protocols to diagnose and monitor disease progression.

Pneumonitis after Palliative Thoracic Radiotherapy +/- Immunotherapy: A Retrospective Propensity-Matched Cohort Study

PURPOSE/OBJECTIVE(S)

Patients (pts) with advanced lung cancer often receive combined palliative thoracic radiotherapy (RT) and immune checkpoint inhibitors (ICI). There are limited data assessing the toxicities of combined ICI-RT in this setting. We sought to compare the rates of clinically significant pneumonitis among pts with lung cancer receiving palliative thoracic RT with or without recent or concomitant ICI. We hypothesized there would be a higher rate of grade 2+ pneumonitis among RT pts who received recent or concomitant ICI compared to those who did not.

MATERIALS/METHODS

We retrospectively identified consecutive pts with advanced/recurrent lung cancer from a tertiary academic center who received palliative thoracic RT with recent (defined as within 95 days of RT start) or concomitant ICI (ICI-RT group) between January 2014 and February 2020. Pts were propensity matched in a 1:1 manner (by age, sex, ECOG, RT modality, and RT dose) to lung cancer pts who received palliative thoracic RT without any history of ICI receipt (RT-only group). The presence and grade (CTCAE v5.0) of pneumonitis were independently assessed by two investigators. The primary endpoint was grade 2+ pneumonitis, estimated using the cumulative incidence function and compared between the ICI-RT and RT-only groups using Gray's test. The secondary endpoint was overall survival, estimated using the Kaplan-Meier method and compared between groups using the log-rank test.

RESULTS

A total of 146 pts were included in the study (73 in each group). There were no statistically significant differences between the ICI-RT and RT-only groups with respect to age (median 67.7 vs. 67.6, p = 0.97), sex (52% vs. 52% female, p = 1.00), pre-treatment ECOG 0-1 (74% vs 75%, p = 0.85), or biologically effective dose greater than 45 (48% vs. 48%, p = 1.00). The most common RT regimens were 30 Gy in 10 fractions (33 pts, 23%) and 20 Gy in 5 fractions (18 patients, 12%). A plurality of cases utilized 3DCRT (67 pts, 46%). In the ICI-RT group, the median time from last dose of ICI to the start of palliative RT was 16 days; three pts in this group-initiated ICI while receiving RT treatment. The most common ICI was pembrolizumab (36 pts, 49%). A total of eleven grade 2+ pneumonitis events (nine grade 2 and two grade 3 events) were observed. The ICI-RT group had a higher cumulative incidence of grade 2+ pneumonitis compared with the RT-only group (1-year rate, 12.3% vs. 2.7%, p = 0.029); grade 3 pneumonitis occurred in 1/73 (1.4%) in each group. There was no difference in overall survival between groups (median 239 vs. 218 days, p = 0.76).

CONCLUSION

In pts with advanced lung cancer treated with palliative thoracic RT, recent or concomitant ICI use was associated with a higher cumulative incidence of grade 2+ pneumonitis. However, the incidence of grade 3+ pneumonitis was low (1.4%) regardless of ICI receipt.

Perry Disease: Expanding the Genetic Basis

Background

Perry disease (or Perry syndrome [PS]) is a hereditary neurodegenerative disorder inevitably leading to death within few years from onset. All previous cases with pathological confirmation were caused by mutations within the cytoskeleton-associated protein glycine-rich (CAP-Gly) domain of the DCTN1 gene.

Objectives

This paper presents the first clinicopathological report of PS due to a novel DCTN1 mutation outside the CAP-Gly domain.

Methods

Clinical and pathological features of the new variant carrier are compared with another recently deceased PS case with a well-known pathogenic DCTN1 mutation and other reported cases.

Results and Conclusions

We report a novel DCTN1 mutation outside the CAP-Gly domain that we demonstrated to be pathogenic based on clinical and autopsy findings.

Centripetal Nystagmus, Slow Saccades, Cerebellar Ataxia, and Parkinsonism in a Patient With Anti-GAD65-Associated Stiff Person Syndrome Spectrum Disorder

ABSTRACT

A 68-year-old woman with positional dizziness and progressive imbalance presented for vestibular evaluation. Examination was notable for spontaneous downbeat nystagmus (DBN), horizontal and vertical gaze-evoked nystagmus (GEN) with centripetal and rebound nystagmus, and positional apogeotropic nystagmus. There was also mild-moderate slowing of saccades horizontally and vertically and poor fast phases with an optokinetic stimulus. Further consultation by a movement disorder specialist uncovered asymmetric decrementing bradykinesia and rigidity, masked facies, and a wide-based stance without camptocormia. Screening serum laboratory results for metabolic, rheumatologic, infectious, heavy metal, endocrine, or vitamin abnormalities was normal. Surveillance imaging for neoplasms was unremarkable, and cerebrospinal fluid (CSF) analysis was negative for 14-3-3 and real-time quaking-induced conversion (RT-QuIC). However, her anti-glutamic acid decarboxylase-65 (GAD65) immunoglobulin G (IgG) level was markedly elevated in serum to 426,202 IU/mL (reference range 0-5 IU/mL) and in CSF to 18.1 nmol/L (reference range <0.03 nmol/L). No other autoantibodies were identified on the expanded paraneoplastic panel. The patient was referred to neuroimmunology, where torso rigidity, spasticity, and significant paravertebral muscle spasms were noted. Overall, the clinical presentation, examination findings, and extensive workup were consistent with a diagnosis of anti-GAD65-associated stiff person syndrome-plus (musculoskeletal plus cerebellar and/or brainstem involvement). She was subsequently treated with intravenous immunoglobulin (IVIg) and has been stable since commencing this therapy. In patients with centripetal nystagmus, especially in association with other cerebellar findings, an autoimmune cerebellar workup should be considered.

Non-staged bilateral Globus Pallidus Internus deep brain stimulation lead revision using intraoperative MRI: a case report and literature review

BACKGROUND

Deep brain stimulation (DBS) lead revision due to suboptimal therapy is common but there is no standardised protocol. We describe a novel technique using iMRI to perform concurrent new Globus Pallidus Internus (GPi) DBS lead implantation and old lead removal in a dystonia patient.Case-description: A 60-year-old woman with medication and neurotoxin-refractory isolated cervical dystonia underwent awake bilateral GPi DBS surgery with MER-guided lead implantation. She initially had a favourable response but later reported suboptimal benefit despite reprogramming. MRI demonstrated suboptimal lead placement and MRI-guided revision surgery under general anesthesia was planned. The goal was to place new leads superior and medial to the existing leads. Using a 1.5 T iMRI and the ClearPoint^® NeuroNavigation system, new leads were placed through the existing burr holes, into the new targets with radial errors < 0.08mm bilaterally without crossing the old leads. The old leads were then removed and the new leads connected to the existing pulse generator. The patient tolerated the procedure well and had improved side-effect profile at all contacts at 1-month follow-up.

CONCLUSIONS

Non-staged iMRI-guided DBS revision surgery under general anesthesia is technically feasible and is an alternative strategy to a staged iMRI-guided revision surgery or an awake MER-guided revision surgery in select patients.