Basal ganglia T1 hyperintensity in LGI1-autoantibody faciobrachial dystonic seizures

Abstract

Objective:To characterize the clinical features and MRI abnormalities of leucine-rich glioma-inactivated 1 (LGI1)-autoantibody (Ab) faciobrachial dystonic seizures (FBDS).Methods:Forty-eight patients with LGI1-Ab encephalopathy were retrospectively identified by searching our clinical and serologic database from January 1, 2002, to June 1, 2015. Of these, 26 met inclusion criteria for this case series: LGI1-Ab seropositivity and FBDS. In a separate analysis of all 48 patients initially identified, the MRIs of patients with (n = 26) and without (n = 22) FBDS were compared by 2 neuroradiologists blinded to the clinical details.Results:The median age of the 26 included patients was 62.5 years (range 37–78); 65% were men. FBDS involved arm (26), face (22), and leg (12). Ten were previously diagnosed as psychogenic. Ictal EEGs were normal in 20 of 23 assessed. Basal ganglia T1 and T2 signal abnormalities were detected in 11 patients (42%), with excellent agreement between neuroradiologists (κ scores of 0.86 and 0.93, respectively), and included T1 hyperintensity alone (2), T2 hyperintensity alone (1), or both (8). The T1 hyperintensities persisted longer than the T2 hyperintensities (median 11 weeks vs 1 week, p = 0.02). Improvement with immunotherapy (18/18) was more frequent than with antiepileptic medications (10/24). A separate analysis of all 48 patients initially identified with LGI1-Ab encephalopathy showed that basal ganglia MRI abnormalities were present in 11 of 26 with FBDS but not present in those without FBDS (0/22) (p < 0.001). In contrast, mesial temporal MRI abnormalities were less common among those with FBDS (42%) than those without (91%) (p < 0.001).Conclusions:Basal ganglia T1 hyperintensity is a clinically useful MRI biomarker of LGI1-Ab FBDS and suggests a basal ganglia localization.

Global brain atrophy and metabolic dysfunction in LGI1 encephalitis: A prospective multimodal MRI study

“…We did not find extratemporal lesions, i.e. basal ganglia hyperintensities in our patients including FBDS cases in contrast to earlier studies [9,10,14,30,31]. Nevertheless, we found that higher volume of the putamen was associated with better cognition measured by ACE test at 23.4±7.6 months indicating the affection of the basal ganglia also in our studies, and that basal ganglia atrophy may affect functional outcomes in patients with LGI1 encephalitis.…”

“…For such correlation, we used (i) midline structures with significant group differences (brainstem, combined volume of the mid-posterior and central parts of the corpus callosum); (ii) the bilateral volumes of those structures where significant difference were shown between patients and controls for both sides (cerebral white matter, cerebellar gray matter); (iii) and the bilateral volumes of lateral ventricles (a general marker of global atrophy) along with putamen and caudate, i.e. areas that have been shown to be highly affected by the disease [7][8][9][10].…”

“…The putamen is actively involved in a variety of cognitive functions such as episodic memory, cognitive control and category learning [38], and its inter-connection with frontal areas and hippocampus play an important role in cognition [39,40]. Hyperintensities previously published in VGKC and LGI1 encephalitis/FBDS pointed to the affection of these structures, and a very recent study reported correlation between longer duration of FBDS and pallidum volume [9,14,[28][29][30]. Although we found decreased hippocampal volumes compared to matched controls, hippocampal volumetry did not correlate with ACE and mRS outcomes.…”

“…While patients with early immunotherapy may have a good prognosis [2,3], cognitive deficit develop in most [4,5]. Structural magnetic resonance imaging (MRI) showed extratemporal T2 hyperintensities in the early phase with faciobrachial (dys)tonic seizures (FBDS) and reduced volume of the whole brain one year after FBDS [6][7][8][9][10]. Glucose metabolism is also abnormal in areas outside of the limbic structures [8,[11][12][13].…”

Beyond the limbic system: disruption and functional compensation of large-scale brain networks in patients with anti-LGI1 encephalitis

“…Imaging analyses during this early disease stage revealed alterations of basal ganglia metabolism using FDG-PET6 11 and transient T1 and T2 basal ganglia hyperintensities contralateral to the side of FBDS 6. Another recent study linked hypermetabolism of the primary motor cortex and frontal cortex EEG changes to contralateral FBDS 5…”