Functional magnetic resonance imaging of internet addiction in young adults

Table 1 Resting state functional magnetic resonance imaging studies in internet addiction disorder

Ref.	Design and aims	Participants	Diagnostic criteria and evaluation scales	fMRI methods	fMRI results
Liu et al[18]	Resting state fMRI study	n = 38, age range 18-25 yr	IAD: Beard's DQIA "5 +	Scanner: 3 T	Between group significant effects:
	Aim: To analyze encephalic	Medication free 100%	1 criteria" plus any one	FMRI Scan duration:	ReHo
	functional characteristic of	Right-handed 100%	of: ≥ 6 h/d for 3 mo	9 min	IAD > NC in: Cerebellum,
	IAD under resting state	Normal neurological examination 100%	Decline in academic performance	Software used: SPM2	brainstem, R CG, bilateral PH, R FL, L SFG, L precuneus, R PoCG,
		No comorbid psychiatric disorders	Unable to maintain normal school learning	ReHo measured by means of KCC	R MOG, R ITG, L STG, MTG
		Groups: IGA n = 19		Signal analyzed:
		Mean age: 21.0 ± 1.3 yr		BOLD
		Males n = 11 (57.9%)		Both whole brain and
		NC n = 19 (50%)		ROI based analysis
		Mean age: 20.0 ± 1.8 yr
		Males n = 11 (57.9%)
Dong et al[21]	Resting state fMRI study	n = 29, age 24.2 ± 3.8 yr	IGD: YIAT ≥ 80	Scanner: 3 T	Between group significant effects:
	Aim: To investigate the	Males 100%	> 80% of the online time	FMRI Scan duration:	ReHo
	effects of long-time online	Medication free 100%	was spent playing	9 min	IGA > NC in: Bilateral brainstem,
	game playing on visual and	Right-handed 100%	videogames	Software used:	bilateral IPL, L posterior
	auditory brain regions	No nicotine, cocaine or marijuana use	BDI < 5; MINI: No Axis I	DPARSF; ReHo measured by	cerebellum, L MiFG; IGA < NC in: L STG, L ITG, L OL,
		Groups: IGD n = 15; Age 24.2 ± 3.5 yr	psychiatric disorders	means of KCC; Signal analyzed:	L PL
		NC n = 14; Age 24.6 ± 3.8 yr		BOLD; Both whole brain and
				ROI based analysis
				Seed based connectivity analysis
1Dong et al[31]	Resting-state and task	n = 71	IGD: Young's IAT ≥ 50	Scanner: 3 T	Between group significant effects:
	related fMRI	Age 22.35	> 80% of the online time	Rs fMRI Scan	RsFc
	Aim: To examine the Fc of	Males 100%	was spent playing	duration: 7 min	IGD < NC in: Total ECN and L
	ECN during both resting	Medication free 100%	videogames	Software used: REST,	ECN
	state and Stroop task	Right-handed 100%	BDI < 5	DPARSF, SPM8, FSL
	performing	No DSM 5 psychiatric disorders	MINI: No Axis I psychiatric disorders	Signal analyzed: BOLD
		Groups: IGD n = 35		Whole brain analysis
		Age 22.2 ± 3.8 yr
		NC n = 36
		Age 22.8 ± 2.4 yr
Kim et al[32]	Resting state fMRI study	n = 45	For all participants:	Scanner: 3 T	Between group significant effects:
	Aim: To compare the brain	Males 100%	WAIS III ≥ 80	Rs fMRI Scan	ReHo
	functioning of IGD, AUD,	Medication free 100%	For IGD: YIAT ≥ 70	duration: 8 min	(1) IGD vs NC
	and NC during resting state	Groups: IGD n = 16	> 4.5 h/d were spent	Software used:	IGD > NC in L PCC
		Age 21.6 ± 5.9 yr	playing online	DPARSF, SPM8,	IGD < NC in R STG
		AUD n = 14	For AUD: SCID criteria	REST	(2) IGD vs AUD
		Age 28.6 ± 5.9 yr	AUDIT-K	ReHo measured by	IGD < NC in R STG
		NC n = 15	< 2 h/d were spent	means of KCC	(3) AUD vs NC
		Age 25.4 ± 5.9 yr	online	Signal analyzed:	AUD > NC in R PCC, R insula, L
		IGD were significantly	Other scales	BOLD	MTG
		younger than AUD	administered to all	Whole brain analysis	AUD < NC in R ACC
		(P < 0.01)	subjects:
			BDI: IGD and AUD > NC (P < 0.01)
			BAI: AUD > NC (P < 0.01)
			BIS-11: IGD and AUD > NC (P < 0.01)
Zhang et al[34]	Resting state fMRI study	n = 115	IGD: CIAS ≥ 67	Scanner: 3 T	Between group significant effects:
	fMRI in young adults with Internet gaming disorder	Males 100%; Medication free 100%	Internet gaming > 14 h/wk for 1 yr	Rs fMRI Scan duration: 7 min	RsFC; L anterior insula
	using rsFC	Right-handed 100%; Groups: IGD n = 74	Playing as the principal online activity	Software used: DPABI, REST, SPM8	IGD > NC in R putamen, R angular gyrus, IFG
	Aim: To study resting-state	age 22.3 ± 2 yr; n = 57 alcohol drinkers	NC: CIAS < 60	Signal analyzed: BOLD	R anterior insula; IGD > NC in ACC, middle CG,
	functional connectivity of	n = 8 cigarette smokers	internet gaming <	Seed based	L angular gyrus, L precuneus,
	the insula in IGD	NC n = 41;	2 h/wk	connectivity analysis	Bilateral SFG and STG
		age 23.0 ± 2.1 yr	Other scales: FTND		L posterior insula
		n = 29 alcohol drinkers	BDI: IGD > NC		IGD > NC in bilateral PoCG, L
		Cigarette use and frequency of alcohol use were higher in IGD with respect to NC (P < 0.05 and P < 0.01)	(P < 0.001); BAI: IGD > NC (P < 0.01)		precentral gyrus, R SMA, STG; R posterior insula; IGD > NC in bilateral STG
		No comorbid psychiatric disorders

¹Only resting state results are showed. AUD: Alcohol use disorder; IAD: Internet addiction disorder; IGD: Internet gaming disorder; NC: Normal controls; AUDIT-K: Korean version of alcohol use disorder identification test; BAI: Beck anxiety inventory; BDI: Beck depression inventory; BIS-11: Barratt impulsiveness scale-version 11; CIAS: Chen internet addiction scale; DQIA: Beard’s diagnostic questionnaire for internet addiction; FTND: Fagerstrom test for nicotine dependence; MINI: Mini international neuropsychiatric interview; SCID: Structured clinical interview for DSM-IV; YIAT: Young’s internet addiction test; WAIS: Wechsler adult intelligence scale; DPARSF: Data processing assistant for resting-state fMRI; KCC: Kendall’s coefficient of concordance; ReHo: Regional homogeneity; RsFC: Resting state functional connectivity; SPM: Statistical parametric mapping; R: Right; L: Left; ACC: Anterior cingulate cortex; CG: Cingulate gyrus; ECN: Executive control network; FL: Frontal lobe; IFG: Inferior frontal gyrus; IPL: Inferior parietal lobule; ITG: Inferior temporal gyrus; MiFG: Middle frontal gyrus; MOG: Middle occipital gyrus; MTG: Middle temporal gyrus; OL: Occipital lobe; PCC: Posterior cingulate cortex; PH: Parahippocampus; PL: Parietal lobe; PoCG: Postcentral gyrus; SFG: Superior frontal gyrus; SMA: Supplementary motor area; STG: Superior temporal gyrus.