Dreaming Characteristics in Non-Rapid Eye Movement Parasomnia and Idiopathic Rapid Eye Movement Sleep Behaviour Disorder: Similarities and Differences

Figures & data

Figure 1 Flowchart of the studied cohort of patients with iRBD and NREM parasomnia.

Abbreviations: n, total number of patients; NREMP, non-REM (NREM) parasomnia; iRBD, idiopathic rapid eye movement (REM) sleep behaviour disorder.

Figure 2 Representative speech graph transcribed from the dream reports of one iRBD and one NREMP patient. Adapted from Mota NB, Vasconcelos NA, Lemos N, et al. Speech graphs provide a quantitative measure of thought disorder in psychosis. PLoS One. 2012;7(4):e34928. Creative Commons.³⁶

Abbreviations: NREMP, non-rapid eye movement parasomnia; iRBD, idiopathic rapid eye movement sleep disorder.

Figure 3 Continued.

Figure 3 Speech graph attributes (SGA) and their definitions adapted from Mota NB, Vasconcelos NA, Lemos N, et al. Speech graphs provide a quantitative measure of thought disorder in psychosis. PLoS One. 2012;7(4):e34928. Creative Commons.³⁶

Table 1 Socio-Demographic and Sleep Parameters for iRBD and NREM Parasomnia Patients with Dream Recollection

Total Number of Patients	iRBD		NREMP		Statistics
	7		20
	Mean	SD	Mean	SD	F	p
Age (years)	32.0	7.37	35.3	9.32	0.714	0.406
BMI (kg/m^2)	29.6**	4.04**	25.2	4.00	5.561	0.027*
	n	%	n	%	χ^2	p
Gender (female)	4	57.1	11	55.0	0.306	0.580
	Median	IQR	Median	IQR	U	p
Sleep Macrostructure
TST (min)	360	35.5	378	68.5	55.0	0.407
WASO (min)	52.7	89.0	62.3	69.3	67.0	0.868
SL (min)	16.5	17.0	17.5	16.1	65.0	0.782
REM L (min)	113	145	104	116.75	67.5	0.890
NREM1 (%)	7.3	4.5	12.1	5.85	35.5	0.056
NREM2 (%)	47.1	16.1	47.1	9.85	44.0	0.580
NREM3 (%)	25.1	19.7	19.7	7.55	27.0	0.017*
REM%	18.3	8.3	21.6	9.85	68.0	0.912
AI	13.4	4.9	17.7	7.7	34.0	0.046*
AHI	3.0	7.6	0.95	3.0	57.5	0.488
PLMI	9.0	10.2	2.45	5.45	38.5	0.077
	n	%	n	%	χ^2	p
Other Sleep Disorders
RLS	1	14.30	3	15.00	0.002	0.963
Hypnopompic Hallucination	1	14.30	1	5.00	0.652	0.419
Bruxism	0	0.00	3	15.00	1.181	0.545
Sleep paralysis	0	0.00	3	15.00	1.181	0.545
OSA	0	0.00	2	10.00	0.756	1.000
Insomnia	0	0.00	2	10.00	0.756	1.000
PLMD	0	0.00	1	5.00	0.363	1.000
Hypnagogic Hallucination	0	0.00	1	5.00	0.363	1.000

Notes: *Denotes statistically significant differences (P < 0.05). **Denotes that one of the iRBD patients was excluded in this calculation because their BMI was not accessible during the study. Group comparisons were performed using one-way ANOVAs for parametric variables, Mann–Whitney U-tests for non-parametric variables, and Pearson’s χ² tests for categorical variables.

Abbreviations: AHI, apnea–hypopnea index; AI, arousal index; BMI, body mass index kg/m²; F, one-way ANOVA; IQR, interquartile range; n, number; NREM, non-rapid eye movement; OSA, Obstructive Sleep Apnea; p, p-value; PLMD, Periodic Leg Movement Disorder; REM, rapid eye movement; REM, rapid eye movement latency; RLS, Restless Leg Syndrome; SL, sleep latency; SD, standard deviation; TST, total sleep time; U, Mann–Whitney U statistics; WASO, wake after sleep onset.

Table 2 Orlinsky Scores of iRBD and NREMP Patients

	iRBD		NREMP		p
	f	%	f	%
Total no. of patients	21		89
0. No dream recall	5	23.81	52	58.43	0.007*
1. Feeling of having dreamt but no memory of it	16	76.19	37	41.57	0.007*
2. Specific topic in isolation or fragments	4	57.14	14	70.00	0.652
3. Several disconnected thoughts, scenes or actions	0	0.00	2	10.00	1.000
4. Short but coherent dream	2	28.57	2	10.00	0.269
5. Detailed dream sequence, 2 events or stages occur	1	14.29	2	10.00	1.000
6. Long detailed dream sequences, 3 or 4 distinct stages	0	0.00	0	0.00	1.000
7. Extremely long sequence of 5 or more stages	0	0.00	0	0.00	1.000

Notes: *(in bold) denotes statistically significant differences (p < 0.05). iRBD, idiopathic rapid eye movement sleep disorder; group comparisons were conducted using Fisher’s exact test.

Abbreviations: %, percentage; f, frequency; NREMP, non-rapid eye movement parasomnia; p, p-value.

Table 3 Characters Frequency and Percentage According to the Hall & Van de Castle Dream Content Analysis

	iRBD		NREMP		p
	f	%	f	%
Characters	7		19
Animals	0	0.00	2	10.52	1.000
Creatures	1	14.29	2	10.52	1.000
Human	6	85.71	15	78.95	1.000
Group human	0	0.00	5	33.3	0.262
Single human	6	100.00	10	66.67	0.262
Indefinite	1	16.67	10	66.67	0.063
Male	3	60.00	1	20.00	0.523
Female	2	40.00	4	80.00	0.523
Familiar	2	33.33	1	6.67	0.184
Unfamiliar	4	66.67	14	93.33	0.184
Family	2	33.33	1	6.67	0.184

Notes: Explanation of terms used in this Table: characters, animals, creatures, and humans refer to the total number of characters, animals, creatures, and humans dreamt, respectively; Group human refers to the total number of characters that consist of two or more individuals who are not individually identified; Single human refers to the total number of characters that are described as individuals; Indefinite refers to the total number of characters whose genders are unidentifiable; Male and Female are the total number of male and female characters, respectively, and percentages are relative to the total number of definite human characters; Familiar refers to the total number of characters that are in one of the following four identity subclasses: family, relatives, Known, and Prominent; Unfamiliar refers to the total number of characters that are in the following identity subclasses: Occupational, Ethnic, Uncertain, and Stranger; Family is the total number of characters coded as family members or relatives. The male/female percentage was calculated by dividing the number of male characters by the total number of male and female characters; Familiarity percentage was calculated by dividing the number of familiar characters by the total number of familiar and unfamiliar characters; family percentage was taken to be the total number of family members or relatives out of total humans; Group percentage was the total number of grouped characters out of total humans; Animal percentage was taken to be the total number of animal characters out of total characters.

Abbreviations: %, percentage; f, frequency; NREMP, non-rapid eye movement parasomnia; iRBD, rapid eye movement sleep disorder.

Table 4 Hall & Van de Castle Analysis of Social Interaction, in Particular, Aggression

	RBD		NREMP
	f	%	f	%
Dreams in which aggression occurs	2	28.57	4	20.00
Total instances of aggression	4		5
Dreamer-involved aggression	3	75.00	5	100.00
Fight response	2	66.67	1	20.00
Flight response	1	33.33	4	80.00
Major indicators
A/C Index	0.44		0.26
Aggressor (%)	0.00		0.00
Physical Aggression Percent (%)	25.00		60.00

Notes: Explanation of terms used: Dreamer-involved aggression refers to the number of instances in which the dreamer was involved in aggression; fight response refers to the number of instances in which the dreamer retaliated or engaged in mutual aggression; flight response refers to the number of instances in which the dreamer receives aggression without retaliation and/or escapes from the situation; and A/C index is the Aggression-per-Character index, calculated by dividing the total instances of aggression by the total number of characters. The aggregate percentage was calculated by dividing the number of instances in which the dreamer initiated an aggressive act by the total number of instances of aggression. The percentage of physical aggression was the number of instances in which aggression was physical, out of the total instances of aggression.

Abbreviations: %, percentage; f, frequency; NREMP, non-rapid eye movement parasomnia; iRBD, rapid eye movement sleep disorder.

Mota NB, Vasconcelos NA, Lemos N, et al. Speech graphs provide a quantitative measure of thought disorder in psychosis. PLoS One. 2012;7(4):e34928. doi:10.1371/journal.pone.0034928

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