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Article Excerpt
The development of motor speech impairment is a frequently reported sequela of surgery for cerebellar tumors that often resolves to normal speech within 6 months. In many of the reported cases to date dysarthria has been preceded by a period of postoperative mutism; however, the current case details the development of transient dysarthria without postoperative mutism following resection of a cerebellar tumor in a 16-year-old boy (TN). The speech profiles included results from perceptual speech assessments and examinations of motor speech function. A mild-moderate dysarthria was evident at 2 weeks postsurgery, resolving to mild dysarthria at 2 months and normal speech at 6 and 12 months postsurgery. Deviant perceptual speech present at 2 weeks postsurgery included all areas of speech production (respiration, phonation, resonance, articulation, and prosody), with a mild reduction in speech intelligibility. Difficulties in sequencing and coordinating nonspeech and speech movements were found to contribute to TN's dysarthria. The resolution of the dysarthria coincided with improvements in these deficits. This case documents that dysarthria after resection of a posterior fossa tumor can develop independent of a period of mutism and furthermore that the dysarthria may be transient, but further research into the mechanisms of recovery is required.
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Disruption to speech production following surgical removal of posterior fossa tumors has been frequently documented in the literature over the past two to three decades. Predominantly these reports have focused on postoperative mutism in the acute phase postsurgery (Aguiar, Plese, Cinquini, & Marino, 1995; Al-Jarallah, Cook, Gascon, Kanaan, & Sigueirra, 1994; Hirsch, Renier, Czernichow, Benveniste, & Pierre-Kahn, 1979; Rekate, Grubb, Aram, Hahn, & Ratcheson, 1985). Estimates of the incidence of motor speech impairment in this group ranges from 8 to 29%, although a higher rate is seen in midline tumors (Catsman-Berrevoets et al., 1999; Pollack, Polinko, Albright, Towbin, & Fitz, 1995).
The term mutism and subsequent dysarthria (MSD) has been proposed to describe the phenomenon where the mute phase is followed by a period of dysarthric speech (van Dongen, Catsman-Berrevoets, & van Mourik, 1994). MSD is most frequently seen in children treated for posterior fossa tumors, and the prognosis is considered good with normal or "near normal" speech abilities at 6 months postsurgery (Aguiar et al., 1995; Bhatoe, 1997; Ozimek et al., 2004; Rekate et al., 1985; van Dongen et al., 1994). Attempts to describe the dysarthric component of MSD have relied predominantly on perceptual analyses of speech. Some studies have labeled the speech disorder as cerebellar or ataxic dysarthria, drawing heavily from the classification system derived for adults with dysarthria by Darley, Aronson, and Brown (1969); however, in many reported cases a comprehensive description of the features observed is lacking (Al-Jarallah et al., 1994; Kai, Kuratsu, Suginohara, Marubayashi & Ushio, 1997; Rekate et al., 1985). Contrary to general opinion regarding the resolution of MSD, a recent study has shown that while recovery of speech following mutism postresection of a posterior fossa tumor is common, only one of seven children recovered normal speech when followed up at least 2.5 years later (Steinbok, Cochran, Perrin, & Price, 2003). The persisting speech disorder in these children was characterized either by a slow rate of speech or slurred speech.
While, MSD has been the focus of many reports, a small number of studies have documented a persistent dysarthria evident at least 6 months following surgery for posterior fossa tumor (PFT) in the absence of a period of mutism (Aarsen, van Dongen, Paquier, van Mourik & Catsman-Berrevoets, 2004; Cornwell, Murdoch, Ward, & Kellie, 2003; Murdoch & Hudson-Tennent, 1994). As yet there is no data available on the incidence of persistent dysarthria following surgery for PFT; however, there are at least 24 cases that have documented dysarthria of this etiology. The literature available reveals a consensus that the severity of the persisting dysarthria is mild and that many of the deviant perceptual speech features noted cluster within the areas of vocal quality and articulation. Examination of the motor speech subsystems in two of the studies (Cornwell et al., 2003; Murdoch & Hudson-Tennent, 1994) provided a pathophysiological basis for the perceptual speech characteristics noted by identifying laryngeal, lip, and tongue (articulatory) function to be the areas of impairment. Furthermore, it has been suggested that the speech disorder is most closely aligned with the ataxic dysarthria classification, although Aarsen et al. (2004) indicated that the speech features were not indicative of any dysarthria cluster. It should also be noted that the...
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