Neural correlates of cognitive set shifting in amyotrophic lateral sclerosis.
OBJECTIVE
Amyotrophic lateral sclerosis (ALS) has been associated with executive dysfunction, particularly in the domain of cognitive set shifting. In a recent event-related potential (ERP) study, shifting-related cortical activity on a complex set-shifting paradigm was found to be attenuated in patients with ALS. Here, we investigated whether this ERP change could also be observed in a simplified set-shifting task adapted for potential clinical use, and in ALS patients without overt cognitive impairment.


METHODS
Twenty-six patients and 28 matched healthy controls (HC) completed a set-shifting paradigm involving two task rules and explicit task cues. Cue-locked ERPs were analyzed.


RESULTS
ALS patients and HC did not differ in response latency or accuracy. In HC, cues that required shifting task rules elicited more positive parietal ERP waveforms than cues that signaled a rule repetition. This shifting-related amplitude modulation was absent in patients with ALS. The attenuation of ERP activity in ALS patients remained significant when participants with possible cognitive impairment were excluded.


CONCLUSIONS
Electrophysiological measures can detect ALS-related changes in the neural substrates of set shifting even when these changes do not become apparent in neuropsychological assessment.


CONCLUSIONS
These findings illustrate the potential utility of ERPs as indicators of cognitive change in ALS.
Department of Neurology, Hannover Medical School, Hannover, Germany. Electronic address: lange.florian@mh-hannover.de.
Florian
F
Lange
Department of Neurology, Hannover Medical School, Hannover, Germany.
Christian
C
Lange
Department of Neurology, Hannover Medical School, Hannover, Germany.
Max
M
Joop
Department of Neurology, Hannover Medical School, Hannover, Germany.
Caroline
C
Seer
Department of Neurology, Hannover Medical School, Hannover, Germany.
Reinhard
R
Dengler
Department of Neurology, Hannover Medical School, Hannover, Germany.
Bruno
B
Kopp
Department of Neurology, Hannover Medical School, Hannover, Germany.
Susanne
S
Petri
D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001921:Brain / Q000503:physiopathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology
Amyotrophic lateral sclerosis; Cognitive impairment; Event-related potential; Executive dysfunction; Posterior switch positivity; Set shifting