Although controls were slightly older and more educated than ALS patients, no statistical differences were found. Results of experimental measures are summarized in . Five of 13 ALS participants (38%) met screening criteria for memory and cognitive dysfunction vs. zero controls while 4 of 13 (31%) met screening criteria for depressive symptoms vs. zero controls. The ALS sample overall had significantly lower MMSE scores (t = −2.16, p < .05) and significantly more depressive symptoms (t = 3.89, p = .002) than controls.
Patients completed the Emotional Faces recognition task with a mean accuracy of 68.59% which was significantly lower than the control mean of 81.94% (t = −2.87, p = .011). The Emotional Faces responses were also analyzed according to the 7 emotional choices (i.e., happy, sad, angry, afraid, surprised, disgusted and neutral). ALS patients’ mean (M) recognition of several emotions fell below a 95% Confidence Interval (CI) of control performance. These emotions were sad (ALS M = 56.41%, SD = 25.04; Controls CI lower-bound = 76.09%), disgusted (ALS M = 57.69%, SD = 35.10; Controls CI lower-bound = 75.06%), angry (ALS M = 71.79%, SD = 22.96; Controls CI lower-bound = 72.99%) and surprised (ALS M = 83.33%, SD = 15.21; Controls CI lower-bound = 90.86%). Of these 4 emotions, 3 had statistically significant differences between groups (sad: t = −3.47, p = .002; disgusted: t = −2.53, p = .022; surprised: t = −2.57, p = .017).
Patients completed the Prosody recognition task with a mean score of 62.80% correct vs. controls mean accuracy of 67.56%. Although the mean ALS performance fell just below a 95% Confidence Interval of control performance (lower-bound = 62.88%), there was no significant difference between the groups (p >.05). When responses to Prosody items were analyzed according to the 7 emotional choices, only the ALS patients’ recognition of surprise fell below a 95% Confidence Interval of control performance (ALS M = 85.42%, SD = 19.82; Controls CI lower-bound = 86.57%).
These results are consistent with emotional perceptual impairment of facial expressions in the majority of the ALS sample as well as a high incidence of abnormal cognitive and depressive symptoms. Eight of the 13 ALS patients (62%) had emotional facial recognition scores that fell below a 95% Confidence Interval for the controls (lower bound = 77.52%). Of these 8 ALS patients, 4 (50%) had neither depressive nor memory and cognitive (dementia) symptoms on screening; two (25%) had both depressive and dementia symptoms; and 2 (25%) had dementia symptoms only. Of the 5 ALS patients whose scores remained within the controls 95% CI, 3 had neither depressive nor dementia symptoms, 1 had both dementia and depressive symptoms, and 1 had depressive symptoms only. None of these frequencies approached significance. Three ALS patients (23%) had Prosody recognition scores below the 95% Confidence Interval for controls (lower bound = 62.88%) while another 3 were below the control mean but above the CI lower bound. Of the 3 patients with impaired Prosody recognition, all had impaired Emotional Face recognition; 2 had neither memory and cognitive nor depressive symptoms on screening; and 1 had dementia symptoms. In total, 8 of the 13 ALS participants had either impaired Emotional Faces or Prosody recognition in comparison to controls.
Correlational analyses in the ALS sample indicated that scores on the Emotional Faces and Prosody tasks were moderately inter-related (r= 0.688, p = .013, 2-tailed). The GDS was not correlated with either the Emotional Faces or Prosody scores. MMSE scores showed a moderate correlation with the Emotional Faces accuracy (r= 0.614, p=.025, 2 tailed) and a trend toward correlation with Prosody accuracy (r=0.513, p=.088, 2 tailed).