Altered patterns of cortical activation in ALS patients during attention and cognitive response inhibition tasks.

Since amyotrophic lateral sclerosis (ALS) can be accompanied by executive dysfunction, it is hypothesised that ALS patients will have impaired performance on tests of cognitive inhibition. We predicted that ALS patients would show patterns of abnormal activation in extramotor regions when performing tests requiring the inhibition of prepotent responses (the Stroop effect) and the inhibition of prior negatively primed responses (the negative priming effect) when compared to healthy controls. Functional magnetic resonance imaging was used to measure activation during a sparse sequence block design paradigm investigating the Stroop and negative priming effects in 14 ALS patients and 8 healthy age- and IQ-matched controls. Behavioural measures of performance were collected. Both groups' reaction times (RTs) reflected the Stroop effect during scanning. The ALS and control groups did not differ significantly for any of the behavioural measures but did show significant differences in cerebral activation during both tasks. The ALS group showed increased activation predominantly in the left middle temporal gyrus (BA 20/21), left superior temporal gyrus (BA 22) and left anterior cingulate gyrus (BA 32). Neither group's RT data showed clear evidence of a negative priming effect. However the ALS group showed decreased activation, relative to controls, particularly in the left cingulate gyrus (BA 23/24), left precentral gyrus (BA 4/6) and left medial frontal gyrus (BA 6). Greater cerebral activation in the ALS group accompanying the performance of the Stroop effect and areas of decreased activation during the negative priming comparison suggest altered inhibitory processing in ALS, consistent with other evidence of executive dysfunction in ALS. The current findings require further exploration in a larger study.

The effect of non-invasive positive pressure ventilation (NIPPV) on cognitive function in amyotrophic lateral sclerosis (ALS): a prospective study.

OBJECTIVES: Neuropsychological investigations have shown a degree of cognitive dysfunction in a proportion of non-demented patients with ALS. Respiratory muscle weakness in ALS can lead to nocturnal hypoventilation, resulting in sleep disturbance and daytime somnolence. Sleep deprivation of this type may cause impairments in cognitive function, but this has not been formally evaluated in ALS. METHODS: Cognitive functioning was evaluated in nine patients with ALS with sleep disturbance caused by nocturnal hypoventilation (NIPPV group), and in a comparison group of 10 similar patients without ventilation problems (control group). The NIPPV group then started non-invasive positive pressure ventilation (NIPPV) at night. After about 6 weeks, change in cognitive function was evaluated. RESULTS: Statistically significant improvement in scores on two of the seven cognitive tests was demonstrated in the NIPPV group postventilation, and a trend towards significant improvement was found for two further tests. Scores in the control group did not improve significantly for these four tests, although an improvement was found on one other test. CONCLUSIONS: Nocturnal hypoventilation and sleep disturbance may cause cognitive dysfunction in ALS. These deficits may be partially improved by NIPPV over a 6 week period. This has important implications for investigations of both cognitive dysfunction in non-demented patients with ALS, and the effect of ventilation on quality of life.

The emotional lability questionnaire: a new measure of emotional lability in amyotrophic lateral sclerosis.

In an ALS Clinic, use of the Pathological Laughter and Crying Scale of Robinson et al. [Robinson RG, Parikh RM, Lipsey JR, Starkstein SE, Price TR. Pathological laughter and crying following stroke: validation of a measurement scale and double-blind treatment study. American Journal of Psychiatry 1993;150(2):286-293] revealed several problems: reliance on self-rating, insufficient period of assessment, inadequate exploration of 'appropriateness of emotion', lack of an item for abnormal smiling, amusement rather than happiness being the cause of laughter in ALS, and a frequency-based rating system. The necessary modifications produced a new Emotional Lability Questionnaire (ELQ) that was tested in 43 ALS patients and 43 healthy controls. The self-rated version of the ELQ was administered as a structured interview to each participant, and the independent-relationship between subscales of the ELQ for both versions, thus confirming its internal validity. Greater emotional lability appeared associated with pseudobulbar symptoms. The question why 14 patients rated themselves as severely labile in the crying domain alone and four in the laughter domain alone, required further study.