SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Expires: February 28, 2011 Estimated average burden hours per response 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* RAVIV GABRIEL (Last) (First) (Middle) C/O BIO-LOGIC SYSTEMS CORP. ONE BIO-LOGIC PLAZA (Street) MUNDELEIN IL 60060 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol BIO LOGIC SYSTEMS CORP [ BLSC ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner X Officer (give title below) Other (specify below) CEO
	3. Date of Earliest Transaction (Month/Day/Year) 01/03/2006
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/03/2006		M		13,125	A	$3.3	392,679	D
Common Stock	01/03/2006		M		937	A	$3.718	393,616	D
Common Stock	01/03/2006		M		22,500	A	$3.267	416,116	D
Common Stock	01/03/2006		M		937	A	$3.1533	417,053	D
Common Stock	01/03/2006		M		17,813	A	$3.6133	434,866	D
Common Stock	01/03/2006		M		17,812	A	$4.2933	452,678	D
Common Stock	01/04/2006		M		22,500	A	$3.2267	475,178	D
Common Stock	01/04/2006		M		938	A	$3.1533	476,116	D
Common Stock	01/04/2006		M		35,625	A	$3.6133	511,741	D
Common Stock	01/04/2006		M		53,438	A	$4.2933	565,179	D
Common Stock	01/05/2006		D		565,179	D	( 1 )	0	D
Common Stock	01/05/2006		D		295,708	D	( 1 )	0	I	See footnote ( 2 )
Common Stock	01/05/2006		D		315,187	D	( 1 )	0	D ( 3 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$3.3	01/03/2006		M			13,125	06/05/2005	06/05/2006	Common Stock	13,125	$0	0	D
Stock Option (Right to Buy)	$3.718	01/03/2006		M			937	08/23/2005	08/23/2006	Common Stock	937	$0	0	D
Stock Option (Right to Buy)	$3.2267	01/03/2006		M			22,500	( 4 )	07/10/2007	Common Stock	22,500	$0	0	D
Stock Option (Right to Buy)	$3.1533	01/03/2006		M			937	( 4 )	08/22/2007	Common Stock	937	$0	0	D
Stock Option (Right to Buy)	$3.6133	01/03/2006		M			17,813	( 4 )	08/25/2008	Common Stock	17,813	$0	0	D
Stock Option (Right to Buy)	$4.2933	01/03/2006		M			17,812	( 4 )	07/22/2009	Common Stock	17,812	$0	0	D
Stock Option (Right to Buy)	$3.2267	01/04/2006		M			22,500	( 4 )	07/10/2007	Common Stock	45,000	$0	0	D
Stock Option (Right to Buy)	$3.1533	01/04/2006		M			938	( 4 )	08/22/2007	Common Stock	1,875	$0	0	D
Stock Option (Right to Buy)	$3.6133	01/04/2006		M			35,625	( 4 )	08/25/2008	Common Stock	53,438	$0	0	D
Stock Option (Right to Buy)	$4.2933	01/04/2006		M			53,438	( 4 )	07/22/2009	Common Stock	71,250	$0	0	D

1. Name and Address of Reporting Person* RAVIV GABRIEL (Last) (First) (Middle) C/O BIO-LOGIC SYSTEMS CORP. ONE BIO-LOGIC PLAZA (Street) MUNDELEIN IL 60060 (City) (State) (Zip)

1. Name and Address of Reporting Person* Raviv Dorit (Last) (First) (Middle) C/O BIO-LOGIC SYSTEMS CORP. ONE BIO-LOGIC PLAZA (Street) MUNDELEIN IL 60060 (City) (State) (Zip)

Explanation of Responses:

1. Disposed of pursuant to the merger agreement among Issuer, Natus Medical Incorporated and Summer Acquisition Corporation in which each share of common stock of the Issuer was exchanged for $8.77 in cash, without interest, on the effective date of the merger.

2. These shares were held by the Raviv Family Limited Partnership.

3. These shares were owned directly by Dorit Raviv, Dr. Raviv's spouse.

4. The options became fully vested upon Issuer stockholder approval of the merger on January 4, 2006.

	/s/ Michael J. Hanley as Attorney-in-Fact	01/05/2006
	** Signature of Reporting Person	Date
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