Non-cleft Velopharyngeal Insufficiency

McConville, Katherine M.; Garland, Catharine B.

doi:10.1007/978-3-030-26191-7_41

Cited by 1 publication

(1 citation statement)

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“…38,127,129,[109][110][111] These atypical features of dystonia support the controversial "negative dystonia" concept, which argues that the overall muscle disturbance in dystonia etiologically occurs due to a defective central regulation of muscle activity, a notion which agrees with the network model for dystonia. 38,72,[134][135][136][137][138][139][140][141][142][143][144][145] Proponents of the negative dystonia hypothesis arguably contend that in addition to the core dystonia feature of spasmodic muscle contractions, hypotonia resulting from the failure to activate a muscle required for the performance of a specific type of movement is an overlooked aspect of dystonia and hence the term "negative dystonia" or "minus dystonia". 38,39,72,134,146,147 To the best of the authors' knowledge, only recently has the concept of negative dystonia been supported in the literature, and so far only in the palate, where negative dystonia of the levator veli palatini, the muscle that normally elevates the velum during phonation, is hypothesized to be responsible for a hypernasal tone of voice in patients with dystonia.…”

Section: Is Scaeo Part Of the Bsp Spectrum?mentioning

confidence: 99%

Debunking the Puzzle of Eyelid Apraxia: The Muscle of Riolan Hypothesis

Tawfik

Dutton

2022

Ophthalmic Plastic &Amp; Reconstructive Surgery

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Apraxia of eyelid opening (AEO) has been defined by the presence of an intermittent nonparalytic bilateral loss of the volitional ability to open the eyes or to maintain the eyelids in a sustained elevated position. It is not known whether the condition represents an apraxia, a dystonia, or a freezing phenomenon, and several different nomenclatorial terms have been suggested for this condition including the so-called AEO (scAEO), blepahrocolysis, focal eyelid dystonia, and so on. The primary goal of this review is to attempt to clarify the pathogenetic mechanisms underlying scAEO as a clinical phenomenon. This review also addresses the issue of whether scAEO is part of the spectrum of blepharospasm (BSP) which includes BSP, dystonic blinks and other dystonic eyelid conditions, or whether it is a separate phenomenologically heterogeneous disease with clinical features that merely overlap with BSP.Methods: A literature review was conducted in PubMed, MEDLINE, PubMed Central (PMC), NCBI Bookshelf, and Embase for several related keywords including the terms "apraxia of eyelid opening," "pretarsal blepharospasm," "blepharocolysis," "eyelid freezing," "eyelid akinesia," "levator inhibition," "blepharospasm-plus," as well as "blepharospasm." The clinical findings in patients with scAEO who fulfilled the classic diagnostic criteria of the disease that were originally set by Lepore and Duvoisin were included, while patients with isolated blepharospasm or dystonic blinks (DB) were excluded. In addition, electromyographic (EMG) studies in patients with scAEO were reviewed in detail with special emphasis on studies that performed synchronous EMG recordings both from the levator muscle (LPS) and the pretarsal orbicularis oculi muscle (OO).Results: The apraxia designation is clearly a misnomer. Although scAEO behaves clinically as a hypotonic freezing phenomenon, it also shares several cardinal features with focal dystonias. The authors broadly categorized the EMG data into 3 different patterns. The first pattern (n = 26/94 [27.6%]) was predominantly associated with involuntary discharges in the OO muscle and has been termed pretarsal blepharospasm (ptBSP). The commonest pattern was pattern no. 2 (n = 53/94 [56.38%]), which was characterized by involuntary discharges in the OO muscle, together with a disturbed reciprocal innervation of the antagonist levator muscle and is dubbed disturbed reciprocal innervation (DRI). This EMG pattern is difficult to discern from the first pattern. Pattern no. 3 (n = 15/94 [15.9%]) is characterized by an isolated levator palpebrae inhibition (ILPI). This levator silence was observed alone without EMG evidence of contractions in the pretarsal orbicularis or a disturbed reciprocal relation of both muscles.Conclusion: EMG evidence shows that the great majority (84%) of patients show a dystonic pattern, whereas ILPI (16%) does not fit the dystonic spectrum. The authors propose that a spasmodic contraction of the muscle of Riolan may be the etiological basis for levator inhibition in patients with ...

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