Table 2

Functional imaging studies that have correlated cerebral resting-state activity with cognitive performance in Huntington’s disease

Study	Subjects	Imaging technique/procedure	Cognitive tasks	Evidence of correlation?^*			Comments and additional findings

				Striatum	Frontal lobe	Temporal lobe
Tanahashi et al (40)	16 H 6 C	¹³³Xe SPECT	MMSE	N/A	↓	↓	Reduced frontotemporal rCBF assoc. with deficits in MMSE
Berent et al (39)	15 H 15 C	¹⁸FDG PET	WAIS, WMS	↓	N/A	N/A	Caudate hypometabolism assoc. with deficits in memory and verbal learning performance
Kuwert et al (48)	23 H 21 C	¹⁸FDG PET	WAIS, BVRT, d2 test, Raven’s	↓	↓	↓	Lentiform hypometabolism assoc. with severity of chorea Frontoparietal hypometabolism assoc. with deficits in episodic memory, reasoning, visuomotor abilities and attention
Brandt et al (54)	21 H 8 C^†	[¹¹C]3-Nmethylspiperone PET	TMT, SDMT	↓	N/A	N/A	Binding in the caudate assoc. with deficits in tests of rapid coding and set alternation Binding in the putamen assoc. with duration of illness
Hasselbalch et al (41)	18 H 19 C	^99mTc-HMPAO SPECT	WCST, BDT, FWRT	↓	↓	N/A	Reduced caudate rCBF assoc. with deficits in WCST Reduced frontal rCBF assoc. with deficits in BDT and FWRT
Bäckman et al (34)	5 H 5 C	[¹¹C]SCH [¹¹C]raclopride PET	WCST, TMT, Tower of Hanoi test, verbal fluency test, Rey–Osterreith Complex Figure test	↓	↓	No	Reduced striatum D₁ dopamine, D₂, DAT binding assoc. with executive function, visuospatial skills, episodic memory, verbal fluency, perceptual speed and reasoning deficits
Lawrence et al (55)	23 H^‡ 20 C	[¹¹C]raclopride PET	CANTAB (spatial recognition memory, spatial span, spatial working memory)	↓	N/A	N/A	Caudate and putamen D₁ and D₂ receptor binding assoc. with deficits in verbal fluency, pattern recognition, spatial information span, complex problem solving and sequence generation
Sanchez-Pernaute et al (57)	10 H 10 C	MRS	TMT, Stroop, SDMT, verbal fluency test	No	N/A	N/A	Atrophy in the striatum and reduced NAA levels, but not corr. with cognitive tests
Kremer et al (50)	26 H	¹⁸FDG PET	MMSE, WAIS, verbal fluency test, immediate recall test, paired associates test	↓	N/A	N/A	Caudate and putamen hypometabolism assoc. with functional capacity, but not assoc. with cognitive measures.
Bachoud-Levi et al (51)	5 H	¹⁸FDG PET	MMSE, TMT, Stroop, RAVLT, Raven’s, Token Test, JLOT	↑	N/A	N/A	Caudate and putamen hypermetabolism assoc. with deficits in attention and executive functioning
Pavese et al (56)	12 H	[¹¹C]raclopride PET	MMSE, TMT, Stroop, WMS, SDMT, Digit Span, BDT, CANTAB, Tower of London test	↓	↓	↓	Reduced [¹¹C]raclopride over time in striatum, frontal and temporal lobes. Reduced striatial [¹¹C]raclopride corr. with Tower of London test

Assoc. = associated; BDT= Block Design test; BVRT= Benton Visual Retention Test; CANTAB = Cambridge Neuropsychological Test Automated Battery; C = controls; corr. = correlated; d2 test = visuomotor test; DAT = dopamine transporter; FWRT= Face and Word Recognition Test; H = patients with Huntington’s disease; JLOT = Judgment of Line Orientation Task; MMSE = Mini-Mental State Examination; MRS = magnetic resonance spectroscopy; NAA = N-acetyl aspartate; PET= positron emission tomography; Raven’s = Raven’s Standard Progressive Matrices; RAVLT = Ray Auditory Verbal Learning Test; rCBF = regional cerebral blood flow; SDMT =Symbol Digit Modality Test; SPECT= single-photon emission computed tomography; TMT= Trail-Making Test; WAIS = Wechsler Adult Intelligence Scale; WMS = Wechsler Memory Scale; WSCT = Wisconsin Card Sorting Test.
↵* ↑ = increased activity; ↓ = decreased activity; N/A = region was not assessed; No = no correlation.
↵† Subjects at risk for Huntington’s disease (HD).
↵‡ 5 symptomatic patients with HD and 17 asymptomatic mutation carriers.