Enlarged high frequency oscillations of the median nerve somatosensory evoked potential and survival in amyotrophic lateral sclerosis

ObjectiveA large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS.MethodsA total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis.ResultsPatients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively).ConclusionsThe HFO amplitude in ALS is increased, but does not predict survival.SignificanceThe enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons.     

DRPLA: An unusual disease or an underestimated cause of ataxia in Brazil?

BackgroundDentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant spinocerebellar ataxia caused by pathological expansion of CAG trinucleotide repeats in the ATN1 gene. Most cases were described in patients from Japanese ancestry who presented with adult-onset progressive cerebellar ataxia associated with cognitive impairment, choreoathetosis and other movement disorders. DRPLA has been rarely described in Brazilian patients.MethodsWe performed a retrospective observational multicentric study including six different Neurology Centers in Brazil. All patients with genetically confirmed diagnosis of DRPLA had their medical records evaluated and clinical, genetic and neuroimaging features were analyzed.ResultsWe describe of eight Brazilian patients (5 male, 3 female) from four nuclear families with genetically confirmed DRPLA. The most common neurological features included cerebellar ataxia (n = 7), dementia (n = 3), chorea (n = 2), psychiatric disturbances (n = 2), progressive myoclonic epilepsy (n = 2) and severe bulbar signs (n = 1). Progressive myoclonic epilepsy was observed in two juvenile-onset cases before 20-year. A large CAG trinucleotide length was observed in the two juvenile-onset cases and genetic anticipation was observed in all cases. Neuroimaging studies disclosed cerebellar atrophy (n = 6), as well as brainstem and cerebellar atrophy (n = 2) and leukoencephalopathy (n = 1).ConclusionThe patients described herein reinforce that clinical features of DRPLA are highly influenced by age of onset, genetic anticipation and CAG repetition lengths. There is a large complex spectrum of neurological features associated with DRPLA, varying from pure cerebellar ataxia to dementia associated with other movement disorders (myoclonus, choreoathetosis). DRPLA is an unusual cause of cerebellar ataxia and neurodegeneration in Brazilian patients.     

Evaluating Benefit-risk Decision-making in Spinal Muscular Atrophy: A First-ever Study to Assess Risk Tolerance in the SMA Patient Community

PurposePatients’ perceptions of benefit–risk are essential to informing the regulatory process and the context in which potential therapies are evaluated. To bring this critical information to regulators, Cure SMA launched a first-ever Benefit-Risk Survey for spinal muscular atrophy (SMA) to characterize decision-making and benefit–risk trade-offs in SMA associated with a potential therapy. We hypothesized that risk tolerance would be correlated with SMA type/severity and disease progression. This article presents the results of a benefit–risk survey to enhance understanding of how patients with SMA and caregivers evaluate specific benefits and risks associated with potential therapies.MethodsAffected adults, representing all SMA types (I–IV) within the Cure SMA database, and caregivers of affected individuals of all ages/types were invited via e-mail to participate. Best–worst scaling (BWS) was used to assess participants’ priorities on benefit–risk trade-offs, as it provides higher discrimination and importance scaling among tested attributes. Twelve potentially clinically meaningful treatment benefits and 11 potential risks (ranging in severity and immediacy) were tested. Multiple factors were correlated with individual responses, including: SMA type/disease severity, stage of disease, respondent type, sex, and quality of life/level of independence (current and expected). Survey respondents were also evaluated for "risk-taking attitudes."FindingsA total of 298 responses were evaluated (28% affected adults and 72% caregivers, mostly parents). Most respondents were diagnosed >5 years ago (67.3%), with 22.1% SMA type I, 45.6% SMA type II, and 27.9% SMA type III. No strong correlation was found between risk tolerance and SMA type, stage of disease progression, respondent type, sex, quality of life assessment, or rated levels of independence. Irrespective of SMA type, respondents consistently rated the following risks, associated with a potential treatment, as "least tolerable": life-threatening allergic reactions; 1 in 1000 risk of life-threatening side effects leading to possible organ failure; or worsening quality of life. Furthermore, all SMA type respondents rated these risks as "most tolerable": invasive mode of treatment administration (including need for general anesthesia); side effect of dizziness; and other common side effects such as nausea, vomiting, loss of appetite, headaches, back pain, or fatigue.ImplicationsWith the approval of the first SMA treatment, these findings offer a unique opportunity to assess and characterize baseline risk-tolerance in SMA against which to evaluate future SMA treatment options. Although differences had been expected in risk tolerance among respondents based on disease baseline and certain patient attributes, this was not observed. Survey results should inform future SMA drug development and benefit–risk assessments.