Table 3

Functional imaging studies that have assessed cerebral activity during cognitive performance in Huntington’s disease

Study	Subjects	Imaging technique/procedure	Cognitive tasks	Differences in activation?^*			Comments and additional findings

				Striatum	Frontal lobe	Temporal lobe
Goldberg et al (58)	11 H 11 Sc	¹³³Xe SPECT	WAIS, WCST	No	↑	No	Increased frontal activation assoc. with WCST performance
Weinberger et al (59)	14 H 14 C	¹³³Xe SPECT	WAIS, WCST	No	No	N/A	No association between frontal rCBF and WCST performance
Deckel et al (60)	7 H 9 C	⁹⁹Tc SPECT	Stroop Colour Test, Digital Symbol Modalities Test, Word Test, Maze Test	↓	No	No	Reduced caudate rCBF during Maze Test
Clark et al (61)	3 H	fMRI	Maze Test	↓	↑	No	Reduced caudate and parietal fMRI signal and increased frontal fMRI signal during Maze testing
Voermans et al (62)	12 H 18 C	fMRI	WAIS, WMS, CVLT, route recognition test	↓	↑	↑	Reduced caudate activity and increased temporal activity during route recognition
Kim et al (63)	8 H	fMRI	MMSE, SRTT	No	↓	No	Reduced activation in frontal and occipital regions during SRTT

C = controls; CVLT = California Verbal Learning Test; fMRI = functional magnetic resonance imaging; H = subjects with Huntington’s disease; MMSE = Mini-Mental State Examination; rCBF=regional cerebral blood flow; Sc = subjects with schizophrenia; SPECT = single-photon emission computed tomography; SRTT = serial reaction time task paradigm; WAIS = Wechsler Adult Intelligence Scale; WCST = Wisconsin Card Sorting Test; WMS = Wechsler Memory Scale.
↵* ↑ = greater activation in H; ↓ = less activation in H; No = no differences; N/A = region was not assessed.