Dysarthria in Adults with Cerebral Palsy: Clinical Presentation, Communication, and Classification

Background: Cerebral palsy (CP) is the most prevalent disorder in neuropediatrics. About 80% of the patients show symptoms of dysarthria frequently resulting in major restrictions of everyday communication. However, to date, there is no comprehensive description of the clinical features of dysarthria and their specific impact on communicative variables (e.g., intelligibility). Adult patients with CP have been neglected particularly in the relevant literature, even though there are several reports indicating that limitations of activity and participation increase throughout adulthood due to functional deficits of speech. Moreover, previous studies assume that the motor subtypes of CP manifest in distinct symptom patterns of speech (dysarthria syndromes), which reflect the underlying pathomechanism (spasticity, dyskinesia, and ataxia). This presumption is not confirmed by empirical data. The aims of the study were (1) to systematically describe the clinical presentation of dysarthria in adults with CP, (2) to identify dysarthric symptoms that especially account for the communication deficits, and (3) to compare patient groups with different CP types regarding their dysarthria syndrome and the overall severity of the speech and communication disorder.

Methods: A total of 45 adults (age, median = 23 [18-56] years, 20 females) with different motor subtypes of CP participated in the study. The Bogenhausen Dysarthria Scales provided a detailed neurophonetic profile for each patient. In several listening experiments, we assessed two communication-relevant parameters (intelligibility and naturalness). For dysarthria syndrome classification, we applied a statistical approach.

Results: A pronounced severity of dysarthria became evident in the majority of patients. The most prominent symptoms affected voice quality as well as articulatory precision and rate. We documented substantial reductions of intelligibility and naturalness, which were predicted by articulatory and prosodic features of dysarthria. Although the overall severity of the speech and communication disorder differed between motor subgroups (with patients of the dyskinetic variant of CP being more severely affected), we found dissociations between CP type and dysarthria syndrome in several cases.

Conclusion: Adults with CP have to cope with significant limitations of communication as a consequence of dysarthric speech. Diagnostics and treatment should therefore target communication-relevant aspects to orient toward the patients’ everyday social interactions. The motor subtype of CP provides only limited information about the clinical presentation of dysarthria. For the interpretation of this result, factors associated with the early brain damage in CP might be considered.