Faciobrachial dystonic seizures: the influence of immunotherapy on seizure control and prevention of cognitive impairment in a broadening phenotype.

Voltage-gated potassium channel complex antibodies, particularly those directed against leucine-rich glioma inactivated 1, are associated with a common form of limbic encephalitis that presents with cognitive impairment and seizures. Faciobrachial dystonic seizures have recently been reported as immunotherapy-responsive, brief, frequent events that often predate the cognitive impairment associated with this limbic encephalitis. However, these observations were made from a retrospective study without serial cognitive assessments. Here, we undertook the first prospective study of faciobrachial dystonic seizures with serial assessments of seizure frequencies, cognition and antibodies in 10 cases identified over 20 months. We hypothesized that (i) faciobrachial dystonic seizures would show a differential response to anti-epileptic drugs and immunotherapy; and that (ii) effective treatment of faciobrachial dystonic seizures would accelerate recovery and prevent the development of cognitive impairment. The 10 cases expand both the known age at onset (28 to 92 years, median 68) and clinical features, with events of longer duration, simultaneously bilateral events, prominent automatisms, sensory aura, and post-ictal fear and speech arrest. Ictal epileptiform electroencephalographic changes were present in three cases. All 10 cases were positive for voltage-gated potassium channel-complex antibodies (346-4515 pM): nine showed specificity for leucine-rich glioma inactivated 1. Seven cases had normal clinical magnetic resonance imaging, and the cerebrospinal fluid examination was unremarkable in all seven tested. Faciobrachial dystonic seizures were controlled more effectively with immunotherapy than anti-epileptic drugs (P = 0.006). Strikingly, in the nine cases who remained anti-epileptic drug refractory for a median of 30 days (range 11-200), the addition of corticosteroids was associated with cessation of faciobrachial dystonic seizures within 1 week in three and within 2 months in six cases. Voltage-gated potassium channel-complex antibodies persisted in the four cases with relapses of faciobrachial dystonic seizures during corticosteroid withdrawal. Time to recovery of baseline function was positively correlated with time to immunotherapy (r = 0.74; P = 0.03) but not time to anti-epileptic drug administration (r = 0.55; P = 0.10). Of 10 cases, the eight cases who received anti-epileptic drugs (n = 3) or no treatment (n = 5) all developed cognitive impairment. By contrast, the two who did not develop cognitive impairment received immunotherapy to treat their faciobrachial dystonic seizures (P = 0.02). In eight cases without clinical magnetic resonance imaging evidence of hippocampal signal change, cross-sectional volumetric magnetic resonance imaging post-recovery, after accounting for age and head size, revealed cases (n = 8) had smaller brain volumes than healthy controls (n = 13) (P < 0.001). In conclusion, faciobrachial dystonic seizures can be prospectively identified as a form of epilepsy with an expanding phenotype. Immunotherapy is associated with excellent control of the frequently anti-epileptic drug refractory seizures, hastens time to recovery, and may prevent the subsequent development of cognitive impairment observed in this study.

Contactin-associated protein-2 antibodies in non-paraneoplastic cerebellar ataxia.

BACKGROUND: Relatively few studies have searched for potentially pathogenic antibodies in non-paraneoplastic patients with cerebellar ataxia. METHODS AND RESULTS: We first screened sera from 52 idiopathic ataxia patients for binding of serum IgG antibodies to cerebellar neurons. One strong-binding serum was selected for immunoprecipitation and mass spectrometry, which resulted in the identification of contactin-associated protein 2 (CASPR2) as a major antigen. CASPR2 antibodies were then found by a cell-based assay in 9/88 (10%) ataxia patients, compared to 3/144 (2%) multiple sclerosis or dementia controls (p=0.011). CASPR2 is strongly expressed in the cerebellum, only partly in association with voltage-gated potassium channels. CONCLUSIONS: Prospective studies are now needed to see whether identification of CASPR2 antibodies has relevance for the diagnosis and treatment of idiopathic cerebellar ataxia.

Microanatomical correlates of cognitive ability and decline: normal ageing, MCI, and Alzheimer's disease.

Few microanatomical measures have been reliably correlated with cognitive measures in aging and Alzheimer's disease (AD), particularly in the early stages of degeneration, such as mild cognitive impairment (MCI). However, cortical minicolumn organization has been shown to correlate with cognitive ability in aging monkeys, and the present study extends this finding to humans. We have previously reported that minicolumn spacing of cells in human association cortex is selectively reduced in normal aging (minicolumn thinning). The present study found that such measures detected early disease changes in MCI as well as further minicolumn thinning and disruption in AD. Plaques, tangles, and minicolumns were quantified, postmortem, for 20 controls, 10 MCI, and 20 AD subjects. Minicolumn changes were correlated with premortem cognitive scores (mini-mental state examination and verbal fluency). Two regions were studied from each brain: association cortex in the planum temporale (BA22) and primary auditory cortex (BA41). The relationship between minicolumns and cognitive function was strongest in association cortex, whereas in primary auditory cortex, it appeared to be an epiphenomenon of overall brain atrophy. Microanatomical changes reflecting selective regional vulnerability to AD pathology and differential involvement in the cognitive deficit of AD are therefore detectable in the early stage of MCI.