Ingestive malfunctions and degeneration of ingestion-related brainstem nuclei in spinocerebellar ataxia type 2, 3, 6, and 7

Aims: Dysphagia, which can lead to nutritional deficiencies, weight loss and dehydration, represents a risk factor for aspiration pneumonia. Although clinical studies have reported the occurrence of dysphagia in patients with spinocerebellar ataxia type 2 (SCA2), type 3 (SCA3), type 6 (SCA6), and type 7 (SCA7), there are neither detailed clinical records concerning the kind of ingestive malfunctions which contribute to dysphagia nor systematic pathoanatomical studies of brainstem regions involved in the ingestive process.

Objective: We evaluated the medical records of twelve dysphagic patients who suffered from clinically diagnosed and genetically confirmed spinocerebellar ataxias assigned to the CAG-repeat or polyglutamine diseases (two SCA2, seven SCA3, one SCA6, and two SCA7 patients) and performed a systematic postmortem study on thick serial tissue sections through their ingestion-related brainstem nuclei.

Results: The clinical records revealed that all of the SCA patients were diagnosed with progressive dysphagia and showed dysfunctions detrimental to the preparatory phase of the ingestive process, as well as the lingual, pharyngeal and esophageal phases of swallowing. The vast majority of the SCA patients suffered from aspiration pneumonia, which was the most frequent cause of death in our sample. In addition, upon pathoanatomical examination of all of the SCA2, SCA3, SCA6, and SCA7 patients, a widespread neurodegeneration of the brainstem nuclei involved in the ingestive process was found.

Conclusions: The findings of the present study suggest (1) that dysphagic SCA2, SCA3, SCA6, and SCA7 patients may suffer from dysfunctions detrimental to all phases of the ingestive process, (2) that dysphagia in SCA2, SCA3, SCA6, and SCA7 patients may be associated with widespread neurodegeneration of ingestion-related brainstem nuclei and (3) that rehabilitative swallow therapy which takes specific functional consequences of the underlying brainstem lesions into account might be helpful in preventing aspiration pneumonia, weight loss and dehydration in SCA2, SCA3, SCA6 and SCA7 patients.

Supported by the Deutsche Forschungsgemeinschaft (RU 1215/1–1), the Deutsche Heredo-Ataxie-Gesellschaft (DHAG), the ADCA-Vereniging Nederland and the Bernd Fink-Stiftung (Düsseldorf, Germany).