Language impairment in motor neurone disease

doi:10.1016/S0022-510X(98)00198-1

Journal of the Neurological Sciences

Volume 160, Supplement 1, 1 October 1998, Pages S47-S52

https://doi.org/10.1016/S0022-510X(98)00198-1 Get rights and content

Abstract

Evidence from recent neuropsychological studies of patients with motor neurone disease (MND) has demonstrated that some patients have cognitive impairment. This challenges traditional teaching that MND is a disease with only motor symptoms. Language processing in MND patients has so far not been studied in any depth, but has only been touched upon as a part of general cognition. This study has assessed nine MND subjects on a range of standardised language assessments and compared their performance to that of nine control subjects. Although this is a small experimental sample of subjects, the results of this study indicate that language impairment is present in some patients with MND. The deficits are subtle and only exposed on formal testing. It is not possible to define the nature of the language impairment from this restricted set of data, but there was evidence of some deficits in a sub-group of MND patients on tasks involving naming, auditory comprehension of complex sentences, some semantic tests and spelling. The implications of these findings are discussed in relationship to the clinical management of patients with MND.

Introduction

Motor neurone disease (MND) is traditionally thought of as a disease involving only motor impairment. There is much research defining the various types of motor degeneration, including descriptions of the bulbar involvement and its effect on motor speech production. There is also some documentation of a form of MND that has an accompanying dementia 2, 8, 11, 12, 19. This is generally thought to be an hereditary form of the disease and, in most cases, the cognitive changes precede the onset of motor symptoms.

There has been some interest in the cognitive and language function of patients with other progressive neurological diseases, in particular, multiple sclerosis and Parkinson's disease 1, 6, 7, 14, 17. However, only a small number of studies have been carried out to examine cognitive function in MND.

Evidence of cognitive change with deficits in frontal lobe executive function in patients with MND has been demonstrated in studies by Gallassi et al. 4, 5, Ludolph et al. [16]and Kew et al. [13]. Language function has not been examined in any detail, but has only been considered as a part of more generalised cognition.

Personal observation of patients with MND suggests that some patients appear to have deficits in certain areas of language function. Deficits have been noted in spelling ability, word finding difficulty and in auditory comprehension of more complex input. These deficits are often very subtle and have only come to light when alternative communication is being considered when the patient is severely dysarthric. The impairments are not obvious in everyday conversation and it is unusual for either the patient or the carer to have made any comment about the presence of such difficulties.

The aim of this study was to examine language function more closely in order to establish if language impairment is a feature of MND and to determine the nature and characteristics of the language function of patients with sporadic MND.

A range of language assessments were selected that are sensitive enough to detect subtle deficits in high level language functioning. These tests were administered to a group of subjects with sporadic MND and also to a group of normal controls. The scores of each of the groups were compared to identify any significant differences in performance.

The following research questions were considered:

•
Is there evidence of any deficit in language function in patients with MND?
•
Are there patterns or specific areas of language breakdown?

Section snippets

Subjects

The MND subjects were those surviving patients diagnosed with sporadic MND in the previous three years. All were already known to the speech and language therapy department but had not necessarily received a formal assessment of their communication. The patients all had a confirmed diagnosis of MND from either a neurologist or a geriatrician.

The final study group consisted of nine MND patients (seven male, two female). The age range was 46–83 years, with a mean age of 64 years (S.D., 11.27

Procedure

The subjects from both the study group and the control group were given a verbal explanation of the background to the study and the research questions this study aimed to address.

All subjects were given a range of tests which examined various aspects of language function, namely, naming ability, semantic processing, auditory comprehension of complex sentences, spelling and reading single words.

The assessments were administered over two separate sessions. This was in order to account for

Statistical analysis

The initial analysis was based on a comparison of the performance of the MND subjects with that of the controls. A series of further analyses were then made examining the performance of some of the MND group compared with all of the other subjects, as it appeared that there may be a sub-group within the MND group. Three of the patients scored consistently lower than the rest of the MND subjects on some of the tests. This will be discussed further in Section 5.

In the analysis of the scores, the

Results

All of the subjects in the study, both MND patients and controls, scored within normal limits on the MMSE [3], therefore, none were excluded because of general cognitive impairment. Similarly, none of the subjects were found to be suffering from anxiety or depression on the Hospital Anxiety and Depression Scale (HADS) [24].

General observation of the data suggests that the controls were performing at or near ceiling level on all of the language tests. Most of the MND group were also performing

Discussion

There is a suggestion that while language deficits are not common to all patients with MND, it is possible that there is a sub-group who have some change in language function as demonstrated by the consistently lower scores of three of the MND subjects in this study.

The deficits in performance on the language tests of these outliers appeared to be attributable to the MND process as other confounding factors had been controlled in the study design.

It was difficult from this small set of data to

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View full text

Language impairment in motor neurone disease

Abstract

Introduction

Section snippets

Subjects

Procedure

Statistical analysis

Results

Discussion

Uncited references

J Psychiat Res

Semantic priming in multiple sclerosis

Bull Psychonomic Soc

Thalamic dementia and motor neurone disease

Neurology

Cognitive impairment in motor neurone disease

Acta Neurol Scand

Neuropsychological, electroencephalogram and brain computed tomography findings in motor neurone disease

Eur Neurol

Specific language impairments in Parkinson's disease

Neurology

Amyotrophic lateral sclerosis and its association with dementia, parkinsonism and other neurological disorders: A review

Brain

Cortical function in amyotrophic lateral sclerosis: A positron emission tomography study

Brain

Dementia with motor neurone disease

Bailliere's Clin Neurol