Striatal Dopaminergic Deficit and Sleep in Idiopathic Rapid Eye Movement Behaviour Disorder: An Explorative Study

Figures & data

Table 1 Sociodemographic and Polysomnography Data of iRBD Cases (n=12) and Controls (n=22)

			iRBD N (%)	Controls N (%)	P value (Fisher’s Exact Test)
Gender		Male	11 (91.7)	20 (90.9)	1.000
		Female	1 (8.3)	2 (9.1)
Medication: antidepressant		No	9 (75)	19 (86.4)	641
		Yes	3 (25)	3 (13.6)
		Minimum	Maximum	25th	50th (Median)	75th	P value (2-Tailed; Mann–Whitney U)
Age (years)	iRBD	57.00	79.00	62.25	66.50	69.75	0.732
	Controls	54.00	82.00	60.75	66.00	69.25
TST	iRBD	243.00	475.50	251.75	348.00	400.25	0.262
	Controls	147.00	443.50	208.25	292.00	374.75
WASO (min)	iRBD	27.50	188.40	67.95	101.90	144.03	0.465
	Controls	39.30	230.60	74.95	117.00	169.10
SL (min)	iRBD	9.00	95.50	18.33	33.00	47.38	0.056
	Controls	1.00	166.00	8.25	18.60	30.75
SE (%)	iRBD	52.00	94.80	55.70	75.60	84.84	0.231
	Controls	37.10	88.70	52.25	65.90	78.60
REM Latency (min)	iRBD	50.00	228.00	60.50	83.00	212.00	0.840
	Controls	10.00	345.00	65.25	86.25	136.63
AHI (events/hr)	iRBD	0.00	25.80	0.50	2.80	11.43	0.759
	Controls	0.00	28.50	1.40	2.85	6.88
PLMI (events/hr)	iRBD	1.20	139.10	11.50	28.30	56.50	0.001*
	Controls	0.00	49.00	0.00	3.15	11.18
%N1	iRBD	3.40	38.40	12.03	13.15	21.58	477
	Controls	4.40	59.20	9.95	16.00	23.80
%N2	iRBD	14.30	48.90	28.55	39.60	47.23	866
	Controls	25.20	82.00	30.10	38.60	50.75
%N3	iRBD	15.20	49.90	18.28	22.35	36.78	477
	Controls	13.60	54.90	17.80	21.00	27.20
%REM	iRBD	0.00	31.70	14.00	20.55	26.70	107
	Controls	0.00	31.40	4.50	14.80	20.10

Note: *(in bold), denotes statistically significant results (P< 0.05).

Abbreviations: %, percentage; AHI, apnoea/hypopnoea index; N, number; N1-3, non-REM sleep stages one to three; NREM, non-rapid eye movement sleep; PLMI, periodic limb movement index; REM, rapid eye movement; SE, sleep efficiency; SL, sleep latency; TST, total sleep time; WASO, wakefulness after sleep onset.

Figure 1 Schematic presentation (A) of links between sleep in iRBD and caudate and putamen DaT uptakes. Serial SPECT images from representative iRBD patient (B) show labelling of the basal ganglia with ¹²³I-FP-CIT.

Table 2 DaTSCAN Imaging Characteristics in iRBD Patients (n=12)

DaTSCAN Report Description	Visual/Unquantified Report	Semi-Quantified Analysis*	Uptake Median Values of 123I-Ioflupane SPECT by ROI
Overall result abnormal, n (%)	9 (75)	8 (66.7)	n/a
Abnormal with increased background, n (%)	7 (58.3)	n/a	n/a
Abnormal with bilateral loss of uptake in basal ganglia, n (%)	4 (33.33)	n/a	n/a
Reduction in right putamen uptake, n (%)	3 (25)	8 (66.7)	n/a
Right POR, median (z-score: quartile 1, median, and quartile 3)	n/a	n/a	1.86 (−3.43,-2.2,-1.54)
Reduction in left putamen uptake, n (%)	5 (41.6)	8 (66.7)	n/a
Left POR, median (quartile 1, median, and quartile 3 z-score)	n/a	n/a	1.91(−3.44, −2.35,-1.73)
Reduction in right caudate uptake, n (%)	0 (0)	6 (50)	n/a
Right COR, median (z-score: quartile 1, median, and quartile 3)	n/a	n/a	2.25 (−2.59, −2.02–1.27)
Reduction in left caudate uptake, n (%)	2 (15.4)	6 (50)	n/a
Left COR, median (z-score: quartile 1, median, and quartile 3)	n/a	n/a	2.37 (−3.17,-1.91,-1.15)
Reduction putamen>caudate, n (%)	5 (41.67)	n/a	n/a
Left striatum > right, n (%)	4 (33.33)	n/a	n/a
Right striatum > left, n (%)	1 (0.83)	n/a	n/a

Note: *Abnormal results for quantification defined as z score >±2.

Abbreviations: COR, caudate to occipital ratio; DaTSCAN, 123I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane (123I-FP-CIT) SPECT; L, left; POR, putamen to occipital ratio; R, right; ROI, regions of interest.

Table 3 Correlation Between Polysomnography Derived Sleep Parameters and DaTSCAN Quantification in iRBD Patients (n=12)

Spearman Correlation		Right COR	Left COR	Right POR	Left POR
TST	r	0.622	0.546	0.723	0.585
	P	0.031*	0.066	0.008*	0.046*
WASO	r	−0.531	−0.630	−0.575	−0.501
	P	0.075	0.028*	0.051	0.097
SL	r	−0.004	−0.191	−0.209	−0.256
	P	0.991	0.552	0.514	0.422
SE	r	0.650	0.592	0.804	0.683
	P	0.022*	0.043*	0.002*	0.014*
REM L	r	−0.396	−0.365	−0.108	−0.178
	P	0.228	0.269	0.753	0.600
AHI	r	0.053	0.200	0.016	0.040
	P	0.871	0.533	0.961	0.901
PLMI	r	−0.175	−0.207	0.105	−0.039
	P	0.587	0.519	0.745	0.905
%N1	r	0.266	0.428	0.301	0.484
	P	0.403	0.165	0.343	0.111
%N2	r	−0.189	−0.252	−0.232	−0.287
	P	0.557	0.429	0.469	0.365
%N3	r	−0.119	−0.291	−0.196	−0.291
	P	0.713	0.359	0.540	0.359
%REM	r	0.434	0.711	0.497	0.609
	P	0.159	0.010*	0.100	0.035*

Note: *(in bold), denotes statistically significant results (P< 0.05).

Abbreviations: %, percentage; AHI, apnoea/hypopnoea index; COR, caudate to occipital ratio; DaTSCAN, 123I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane (123I-FP-CIT) SPECT; N, number; N1-3, non-REM sleep stages 1–3; NREM, non-rapid eye movement sleep; P, Spearman’s rank correlation P value; PLMI, periodic limb movement index; POR, putamen to occipital ratio; r, Spearman’s rank correlation rho value; REM, rapid eye movement; SE, sleep efficiency; SL, sleep latency; TST, total sleep time; WASO, wakefulness after sleep onset.